:root {
    --primary-color: #1976D2;
    --secondary-color: #388E3C;
    --accent-color: #F57C00;
    --danger-color: #D32F2F;
    --purple-color: #7B1FA2;
    
    --bg-primary: #f8fafc;
    --bg-secondary: #e8f2ff;
    --bg-card: #ffffff;
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --border-color: #cbd5e0;
    --shadow: 0 2px 10px rgba(25, 118, 210, 0.08);
    --shadow-hover: 0 4px 20px rgba(25, 118, 210, 0.15);
    
    --border-radius: 12px;
    --transition: all 0.3s ease;
    
    /* Tons coloridos sutis */
    --bg-subtle: #f1f5f9;
    --bg-hover: #e2e8f0;
    --text-muted: #64748b;
    --border-subtle: #e2e8f0;
    
    /* Cores de destaque sutis */
    --bg-accent: #fef3e2;
    --bg-success: #f0f9f0;
    --bg-info: #e6f3ff;
    --bg-warning: #fff8e1;
}

[data-theme="dark"] {
    --bg-primary: #121212;
    --bg-secondary: #1e1e1e;
    --bg-card: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --border-color: #404040;
    --shadow: 0 2px 10px rgba(0,0,0,0.3);
    --shadow-hover: 0 4px 20px rgba(0,0,0,0.4);
}

[data-theme="dark"] .hero-section {
    background: linear-gradient(135deg, #1a237e, #2e7d32);
}

[data-theme="dark"] .movement-card {
    background: var(--bg-card);
    border-color: var(--border-color);
}

[data-theme="dark"] .movement-example {
    background: var(--bg-secondary);
    border-left-color: var(--accent-color);
}

[data-theme="dark"] .tip-item:hover {
    background: rgba(33, 150, 243, 0.2);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    background-image: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 50%, var(--bg-subtle) 100%);
    color: var(--text-primary);
    transition: var(--transition);
    padding-bottom: 80px;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
}

/* Header */
header {
    background: var(--bg-card);
    background-image: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-info) 100%);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

[data-theme="dark"] header {
    background: var(--bg-card);
    background-image: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-card) 100%);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px;
    max-width: 1200px;
    margin: 0 auto;
}

header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

/* App Brand / Logo */
.app-brand,
.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--primary-color);
}

.app-brand img,
.logo img {
    height: 32px;
    width: auto;
    display: block;
}

header .app-brand span {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
}

.theme-toggle {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
}

.theme-toggle:hover {
    background: var(--primary-color);
    color: white;
    transform: scale(1.1);
}

/* Sections */
.section {
    display: none;
    padding: 24px 0;
    min-height: calc(100vh - 140px);
}

.section.active {
    display: block;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    flex-wrap: wrap;
    gap: 16px;
}

.section-header h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 700;
}

/* Minimalist Hero Section */
.hero-section {
    text-align: center;
    padding: 80px 0;
    margin-bottom: 60px;
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    position: relative;
}

.hero-content {
    max-width: 600px;
    margin: 0 auto;
    padding: 0 20px;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-icon {
    font-size: 4rem;
    margin-bottom: 16px;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-primary);
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 40px;
    color: var(--text-secondary);
    line-height: 1.6;
    font-weight: 400;
}

/* Hero Actions */
.hero-actions {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.hero-btn {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 16px 32px;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    min-width: 180px;
    justify-content: center;
}

.hero-btn.primary {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.3);
}

.hero-btn.primary:hover {
    background: #1976D2;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(33, 150, 243, 0.4);
}

.hero-btn.secondary {
    background: var(--secondary-color);
    color: white;
    box-shadow: 0 4px 12px rgba(76, 175, 80, 0.3);
}

.hero-btn.secondary:hover {
    background: #388E3C;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(76, 175, 80, 0.4);
}

.hero-btn i {
    font-size: 1.2rem;
}

.feature-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    opacity: 0.9;
}

.feature-item i {
    font-size: 1.5rem;
    background: rgba(255,255,255,0.2);
    padding: 12px;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-item span {
    font-size: 0.9rem;
    font-weight: 600;
}

/* Movement Intro */
.movement-intro {
    text-align: center;
    margin-bottom: 32px;
}

.movement-intro h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    margin-bottom: 8px;
}

.movement-intro p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Cards */
.welcome-card,
.simulation-card,
.results-card,
.formula-card,
.setting-card,
.about-card {
    background: var(--bg-card);
    background-image: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-info) 100%);
    border-radius: var(--border-radius);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-subtle);
    transition: var(--transition);
}

.welcome-card:hover,
.simulation-card:hover,
.results-card:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

/* Cards específicos com cores diferenciadas */
.welcome-card {
    background-image: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-accent) 100%);
}

.simulation-card {
    background-image: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-info) 100%);
}

.results-card {
    background-image: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-success) 100%);
}

.formula-card {
    background-image: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-warning) 100%);
}

.welcome-card h2 {
    color: var(--primary-color);
    margin-bottom: 16px;
    text-align: center;
}

.welcome-card p {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Movement Cards */
.movement-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 40px;
}

.movement-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 0;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    cursor: pointer;
    overflow: hidden;
    position: relative;
}

.movement-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.movement-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-hover);
}

.movement-card:hover .movement-icon {
    transform: scale(1.1);
}

.movement-icon {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 24px;
    text-align: center;
    transition: var(--transition);
}

.movement-icon i {
    font-size: 2.5rem;
    color: white;
}

.movement-content {
    padding: 24px;
}

.movement-content h3 {
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.movement-content h4 {
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.movement-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    margin-bottom: 16px;
}

.movement-example {
    background: var(--bg-secondary);
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    border-left: 3px solid var(--accent-color);
}

.movement-example strong {
    color: var(--accent-color);
}

.movement-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: white;
    border: none;
    border-radius: 8px;
    padding: 12px 20px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    width: 100%;
    font-weight: 600;
    box-shadow: 0 4px 15px rgba(25, 118, 210, 0.3);
}

.movement-btn:hover {
    background: linear-gradient(135deg, #1565C0, #E65100);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(25, 118, 210, 0.4);
}

.movement-btn i {
    font-size: 1rem;
    transition: var(--transition);
}

.movement-btn:hover i {
    transform: translateX(4px);
}

/* Quick Tips */
.quick-tips {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 24px;
    margin-top: 32px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.quick-tips h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: 16px;
    text-align: center;
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
}

.tip-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--bg-secondary);
    border-radius: 8px;
    transition: var(--transition);
}

.tip-item:hover {
    background: rgba(33, 150, 243, 0.1);
    transform: translateY(-2px);
}

.tip-item i {
    color: var(--accent-color);
    font-size: 1.2rem;
}

.tip-item span {
    color: var(--text-primary);
    font-weight: 500;
}

/* Enhanced Section Headers */
.section-header-enhanced {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 32px;
    padding: 24px;
    background: var(--bg-card);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.section-icon {
    font-size: 3rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    flex-shrink: 0;
}

.section-title-group h1 {
    color: var(--primary-color);
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.section-title-group p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.5;
}

/* Enhanced Back Button */
.back-button {
    margin-bottom: 24px;
}

.back-btn {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 12px 20px;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
}

.back-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: translateX(-4px);
}

/* Formula Showcase */
.formula-showcase {
    margin-bottom: 32px;
}

.formula-card-enhanced {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    text-align: center;
}

.formula-card-enhanced h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: 20px;
}

.formulas-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 16px;
}

.formula-display {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.formula-main {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--primary-color);
    display: block;
    margin-bottom: 8px;
}

.formula-display small {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.formula-explanation {
    background: rgba(33, 150, 243, 0.1);
    padding: 12px;
    border-radius: 8px;
    margin-top: 16px;
}

.formula-explanation p {
    color: var(--text-primary);
    font-size: 0.9rem;
    margin: 0;
}

/* Enhanced Simulation Cards */
.simulation-card-enhanced {
    background: var(--bg-card);
    background-image: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-info) 100%);
    border-radius: var(--border-radius);
    padding: 32px;
    margin-bottom: 32px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-subtle);
}

.simulation-header {
    text-align: center;
    margin-bottom: 32px;
}

.simulation-header h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    margin-bottom: 8px;
}

.simulation-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Enhanced Input Groups */
.inputs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}

.input-group-enhanced {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.input-group-enhanced:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.1);
}

.input-icon {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.input-content {
    flex: 1;
}

.input-content label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-size: 1rem;
}

.input-content input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.input-content input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.1);
}

.input-content input::placeholder {
    color: var(--text-secondary);
    opacity: 0.7;
}

/* Enhanced Calculate Button */
.calculate-btn-enhanced {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 16px 32px;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    width: 100%;
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.3);
}

.calculate-btn-enhanced:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(33, 150, 243, 0.4);
}

.calculate-btn-enhanced i {
    font-size: 1.2rem;
}

/* Enhanced Results Section */
.results-section-enhanced {
    margin-top: 32px;
}

.results-header {
    text-align: center;
    margin-bottom: 32px;
    padding: 24px;
    background: var(--bg-card);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.results-header h2 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 8px;
}

.results-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.results-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.calculation-card,
.chart-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.calculation-card h3,
.chart-card h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.charts-showcase {
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
}

.chart-container-enhanced {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: 8px;
    margin-bottom: 16px;
}

.chart-explanation {
    background: rgba(76, 175, 80, 0.1);
    padding: 12px;
    border-radius: 8px;
    border-left: 3px solid var(--secondary-color);
}

.chart-explanation p {
    color: var(--text-primary);
    font-size: 0.9rem;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 8px;
}

.chart-explanation i {
    color: var(--secondary-color);
}

/* Enhanced Calculation Steps */
.calculation-steps-enhanced {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
}

.calculation-steps-enhanced .step {
    margin: 12px 0;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
    line-height: 1.5;
}

.calculation-steps-enhanced .step:last-child {
    border-bottom: none;
    font-weight: 600;
    color: var(--secondary-color);
    background: rgba(76, 175, 80, 0.1);
    padding: 12px;
    border-radius: 6px;
    margin-top: 16px;
}

/* Forms */
.simulation-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-group label {
    font-weight: 600;
    color: var(--text-primary);
}

.input-group input {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.1);
}

.input-help {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 4px;
    display: block;
}

.calculate-btn {
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    color: white;
    border: none;
    padding: 16px 24px;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-top: 16px;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

/* Results */
.results-section {
    margin-top: 32px;
}

.calculation-steps {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: var(--border-radius);
    margin-bottom: 24px;
    border-left: 4px solid var(--primary-color);
}

.calculation-steps h4 {
    color: var(--primary-color);
    margin-bottom: 12px;
}

.calculation-steps .step {
    margin: 8px 0;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
}

.calculation-steps .step:last-child {
    border-bottom: none;
    font-weight: 600;
    color: var(--secondary-color);
}

/* Charts */
.chart-container {
    margin: 24px 0;
    background: var(--bg-card);
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.charts-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.chart-container h4 {
    text-align: center;
    margin-bottom: 16px;
    color: var(--primary-color);
}

.chart-container canvas {
    max-width: 100%;
    height: auto;
}

/* Enhanced History Section */
.history-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 32px;
}

.stat-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 16px;
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.stat-icon {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.stat-content {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.history-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 32px;
    justify-content: center;
}

.action-btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    font-size: 1rem;
}

.action-btn.danger {
    background: var(--danger-color);
    color: white;
}

.action-btn.danger:hover {
    background: #d32f2f;
    transform: translateY(-2px);
}

.action-btn.secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.action-btn.secondary:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.history-list-enhanced {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.history-item {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.history-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.history-item:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    cursor: pointer;
    padding: 8px 0;
}

.history-info {
    display: flex;
    align-items: center;
    gap: 16px;
}

.history-type {
    background: var(--primary-color);
    color: white;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.history-date {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.history-toggle {
    color: var(--text-secondary);
    transition: var(--transition);
}

.history-item:hover .history-toggle {
    color: var(--primary-color);
}

.history-details {
    display: none;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.history-details.expanded {
    display: block;
}

.history-values {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 12px;
    margin-bottom: 20px;
}

.history-value {
    background: var(--bg-secondary);
    padding: 12px;
    border-radius: 8px;
    text-align: center;
    border: 1px solid var(--border-color);
}

.history-value strong {
    color: var(--primary-color);
    display: block;
    margin-bottom: 4px;
    font-size: 0.9rem;
}

.history-actions {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    flex-wrap: wrap;
}

.recreate-btn,
.delete-btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    font-weight: 600;
}

.recreate-btn {
    background: var(--secondary-color);
    color: white;
}

.recreate-btn:hover {
    background: #45a049;
    transform: translateY(-1px);
}

.delete-btn {
    background: var(--danger-color);
    color: white;
}

.delete-btn:hover {
    background: #d32f2f;
    transform: translateY(-1px);
}

/* History */
.history-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.history-item {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.history-item:hover {
    box-shadow: var(--shadow-hover);
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    cursor: pointer;
}

.history-type {
    background: var(--primary-color);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.history-date {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.history-details {
    display: none;
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.history-details.expanded {
    display: block;
}

.history-values {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 12px;
    margin-bottom: 16px;
}

.history-value {
    background: var(--bg-secondary);
    padding: 8px 12px;
    border-radius: 8px;
    text-align: center;
}

.history-value strong {
    color: var(--primary-color);
}

.clear-btn,
.danger-btn {
    background: var(--danger-color);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.clear-btn:hover,
.danger-btn:hover {
    background: #d32f2f;
    transform: translateY(-1px);
}

/* Help Section */
.help-content {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.formula {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: var(--border-radius);
    text-align: center;
    font-size: 1.2rem;
    margin: 16px 0;
    border-left: 4px solid var(--primary-color);
}

.formulas-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.formula small {
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 8px;
}

/* Formula Card Lists */
.formula-card ul {
    margin: 12px 0;
    padding-left: 20px;
}

.formula-card ul li {
    margin: 8px 0;
    line-height: 1.5;
}

.formula-card ul li strong {
    color: var(--primary-color);
}

.example {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: var(--border-radius);
    margin-top: 16px;
    border-left: 4px solid var(--secondary-color);
}

.example h4 {
    color: var(--secondary-color);
    margin-bottom: 8px;
}

/* Enhanced FAQ */
.faq-section {
    margin-top: 40px;
}

.faq-category {
    margin-bottom: 40px;
}

.faq-category h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    padding: 16px 20px;
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
    display: flex;
    align-items: center;
    gap: 12px;
}

.faq-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    background: var(--bg-card);
    border: none;
    padding: 20px;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    transition: var(--transition);
}

.faq-question:hover {
    background: var(--bg-secondary);
}

.faq-question[aria-expanded="true"] {
    background: var(--primary-color);
    color: white;
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
}

.faq-icon {
    font-size: 1.2rem;
    transition: var(--transition);
}

.faq-answer {
    background: var(--bg-secondary);
    padding: 20px;
    border-top: 1px solid var(--border-color);
    animation: slideDown 0.3s ease;
}

.faq-answer p {
    margin-bottom: 8px;
}

.faq-answer p:last-child {
    margin-bottom: 0;
}

/* FAQ Enhanced Content */
.comparison-table {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin: 16px 0;
}

.comparison-item {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.comparison-item h4 {
    color: var(--primary-color);
    font-size: 1.1rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.comparison-item ul {
    list-style: none;
    padding: 0;
}

.comparison-item li {
    margin: 8px 0;
    padding: 4px 0;
    font-size: 0.95rem;
}

.units-table {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 12px;
    margin: 16px 0;
}

.unit-item {
    background: var(--bg-secondary);
    padding: 12px 16px;
    border-radius: 8px;
    border-left: 3px solid var(--accent-color);
    font-size: 0.95rem;
}

.examples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 16px;
    margin: 16px 0;
}

.example-item {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.example-item:hover {
    border-color: var(--primary-color);
    box-shadow: 0 2px 8px rgba(33, 150, 243, 0.1);
}

.example-item h4 {
    color: var(--primary-color);
    font-size: 1rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.example-item p {
    margin: 6px 0;
    font-size: 0.9rem;
    line-height: 1.4;
}

.example-item strong {
    color: var(--secondary-color);
}

/* FAQ Lists */
.faq-answer ol,
.faq-answer ul {
    margin: 12px 0;
    padding-left: 20px;
}

.faq-answer ol li,
.faq-answer ul li {
    margin: 8px 0;
    line-height: 1.5;
}

.faq-answer ol li strong,
.faq-answer ul li strong {
    color: var(--primary-color);
}

/* FAQ Responsive */
@media (max-width: 768px) {
    .comparison-table {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .examples-grid {
        grid-template-columns: 1fr;
    }
    
    .units-table {
        grid-template-columns: 1fr;
    }
    
    .faq-category h3 {
        font-size: 1.3rem;
        padding: 12px 16px;
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        max-height: 0;
    }
    to {
        opacity: 1;
        max-height: 500px;
    }
}

/* Settings */
.settings-content {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
}

.setting-item:last-child {
    border-bottom: none;
}

.setting-info h3 {
    margin-bottom: 4px;
    color: var(--text-primary);
}

.setting-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Switch Toggle */
.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--border-color);
    transition: var(--transition);
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: var(--transition);
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--primary-color);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-card);
    background-image: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-info) 100%);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    padding: 8px 0;
    z-index: 1000;
    box-shadow: 0 -2px 10px rgba(25, 118, 210, 0.15);
}

[data-theme="dark"] .bottom-nav {
    background-image: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-card) 100%);
    border-top: 1px solid var(--border-color);
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 8px 12px;
    text-decoration: none;
    color: var(--text-secondary);
    transition: var(--transition);
    border-radius: 12px;
    min-width: 60px;
}

.nav-item:hover,
.nav-item.active {
    color: var(--primary-color);
    background: rgba(33, 150, 243, 0.1);
}

.nav-item i {
    font-size: 1.2rem;
    margin-bottom: 4px;
}

.nav-item span {
    font-size: 0.7rem;
    font-weight: 500;
}

[data-theme="dark"] .nav-item {
    color: #e0e0e0;
}

/* Simple Footer */
.footer {
    background: var(--bg-secondary);
    background-image: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-info) 100%);
    color: var(--text-secondary);
    margin-top: 40px;
    border-top: 1px solid var(--border-subtle);
}

[data-theme="dark"] .footer {
    background-image: linear-gradient(135deg, #1a1a1a 0%, #2a2a2a 100%);
    color: #d5d5d5;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    flex-wrap: wrap;
    gap: 20px;
}


.footer-brand {
    flex-shrink: 0;
}

.footer-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-contact {
    display: flex;
    gap: 20px;
    flex-shrink: 0;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-color);
}

.footer-logo i {
    font-size: 1.4rem;
}

.footer-brand p {
    color: var(--text-secondary);
    line-height: 1.5;
    font-size: 0.9rem;
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
    font-size: 0.9rem;
    white-space: nowrap;
}

.footer-link:hover {
    color: var(--primary-color);
}

[data-theme="dark"] .footer-link {
    color: #c8c8c8;
}

[data-theme="dark"] .footer-link:hover {
    color: #90caf9;
}


.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding: 15px 0;
    text-align: center;
}

.footer-bottom p {
    margin: 0;
    font-size: 0.8rem;
    color: var(--text-muted);
}

[data-theme="dark"] .footer-bottom {
    border-top: 1px solid var(--border-color);
}

[data-theme="dark"] .footer-bottom p {
    color: #b0b0b0;
}

.footer-bottom a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer-bottom a:hover {
    text-decoration: underline;
}

/* Privacy and Terms Pages */
.privacy-section,
.terms-section {
    padding: 40px 0;
}

.privacy-content,
.terms-content {
    max-width: 800px;
    margin: 0 auto;
}

.privacy-card,
.terms-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 32px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.privacy-card h2,
.terms-card h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.privacy-card h3,
.terms-card h3 {
    color: var(--secondary-color);
    font-size: 1.2rem;
    margin: 20px 0 12px 0;
}

.privacy-card p,
.terms-card p {
    line-height: 1.6;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.privacy-card ul,
.terms-card ul {
    margin: 12px 0;
    padding-left: 20px;
}

.privacy-card li,
.terms-card li {
    margin: 8px 0;
    line-height: 1.5;
}

.privacy-card strong,
.terms-card strong {
    color: var(--primary-color);
}

.usage-grid,
.purpose-grid,
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin: 20px 0;
}

.usage-item,
.purpose-item,
.feature-item {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.usage-item:hover,
.purpose-item:hover,
.feature-item:hover {
    border-color: var(--primary-color);
    box-shadow: 0 2px 8px rgba(33, 150, 243, 0.1);
}

.usage-item h4,
.purpose-item h4,
.feature-item h4 {
    color: var(--primary-color);
    font-size: 1rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.usage-item p,
.purpose-item p,
.feature-item p {
    font-size: 0.9rem;
    margin: 0;
    color: var(--text-secondary);
}

.contact-info {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 8px;
    margin: 16px 0;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 12px 0;
}

.contact-item i {
    color: var(--primary-color);
    font-size: 1.1rem;
    width: 20px;
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.contact-item a:hover {
    text-decoration: underline;
}

/* Responsive Footer */
@media (max-width: 768px) {
    .footer-content {
        flex-direction: column;
        text-align: center;
        gap: 15px;
    }
    
    .footer-links {
        justify-content: center;
        gap: 15px;
    }
    
    .footer-contact {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .footer {
        margin-top: 30px;
    }
    
    .footer-content {
        padding: 15px 0;
        gap: 12px;
    }
    
    .footer-links {
        flex-wrap: wrap;
        gap: 10px;
    }
    
    .footer-link {
    font-size: 0.8rem;
    }
    
    .footer-bottom {
        padding: 12px 0;
    }
    
    .footer-bottom p {
        font-size: 0.75rem;
    }
    
    .usage-grid,
    .purpose-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .privacy-card,
    .terms-card {
        padding: 20px;
    }
}

/* Enhanced Hero Styles */
.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--primary-color);
    color: white;
    padding: 10px 18px;
    border-radius: 25px;
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 28px;
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.3);
}

.hero-badge i {
    font-size: 1rem;
}

.hero-stats {
    display: flex;
    gap: 40px;
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2.8rem;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1;
    margin-bottom: 8px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.stat-label {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 600;
    text-align: center;
}

.hero-visual {
    position: relative;
    z-index: 2;
    padding: 20px;
}

/* Physics Diagram */
.physics-diagram {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 32px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.diagram-header {
    text-align: center;
    margin-bottom: 32px;
}

.diagram-header h3 {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.diagram-header p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin: 0;
}

.diagram-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 24px;
}

.graph-container {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 20px;
    border: 1px solid var(--border-color);
}

.graph-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    text-align: center;
}

.graph-mru,
.graph-mruv {
    height: 120px;
    position: relative;
    background: white;
    border-radius: 8px;
    border: 2px solid var(--border-color);
    margin-bottom: 12px;
    overflow: hidden;
}

.graph-line {
    position: absolute;
    height: 3px;
    background: var(--primary-color);
    top: 20%;
    left: 10%;
    right: 10%;
    border-radius: 2px;
}

.mru-line {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.graph-curve {
    position: absolute;
    height: 3px;
    background: var(--secondary-color);
    top: 20%;
    left: 10%;
    right: 10%;
    border-radius: 2px;
    transform: rotate(-15deg);
    transform-origin: left center;
}

.mruv-curve {
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
}

.graph-points {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}

.point {
    position: absolute;
    width: 8px;
    height: 8px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 2px solid white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.graph-mruv .point {
    background: var(--secondary-color);
}

.graph-explanation {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.graph-explanation i {
    color: var(--primary-color);
    font-size: 0.9rem;
}

.diagram-legend {
    display: flex;
    justify-content: center;
    gap: 32px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    color: var(--text-primary);
    font-weight: 500;
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: 3px;
}

.mru-color {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.mruv-color {
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
}

.animation-track {
    height: 100px;
    background: linear-gradient(90deg, 
        var(--bg-secondary) 0%, 
        var(--bg-secondary) 100%);
    border-radius: 8px;
    position: relative;
    margin-bottom: 20px;
    overflow: hidden;
    border: 2px dashed var(--border-color);
}

.moving-object {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
}

.mru-object {
    background: var(--primary-color);
    animation: moveConstant 3s linear infinite;
}

.mruv-object {
    background: var(--secondary-color);
    animation: moveAccelerated 3s ease-in-out infinite;
}

.animation-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.label-mru {
    color: var(--primary-color);
    font-weight: 500;
}

.label-mruv {
    color: var(--secondary-color);
    font-weight: 500;
}

@keyframes moveConstant {
    0% { left: 10px; }
    100% { left: calc(100% - 50px); }
}

@keyframes moveAccelerated {
    0% { 
        left: 10px; 
        transform: translateY(-50%) scale(0.8);
    }
    50% { 
        left: 50%; 
        transform: translateY(-50%) scale(1.2);
    }
    100% { 
        left: calc(100% - 50px); 
        transform: translateY(-50%) scale(1);
    }
}

/* Enhanced Movement Cards */
.movement-selection {
    margin-bottom: 60px;
}

.movement-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    margin-top: 32px;
}

.movement-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 0;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    cursor: pointer;
    overflow: hidden;
    position: relative;
}

.movement-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.movement-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-hover);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 24px 24px 16px 24px;
}

.movement-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.movement-info h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0 0 4px 0;
}

.movement-info h4 {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 0;
    font-weight: 500;
}

.card-content {
    padding: 0 24px 16px 24px;
}

.movement-description {
    color: var(--text-primary);
    line-height: 1.6;
    margin-bottom: 20px;
}

.movement-details {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 20px;
}

.detail-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.detail-item i {
    color: var(--primary-color);
    width: 16px;
}

.movement-formula {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: 8px;
    text-align: center;
}

.formula-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
    font-weight: 500;
}

.formula-text {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary-color);
    font-family: 'Courier New', monospace;
}

.card-footer {
    padding: 16px 24px 24px 24px;
}

.movement-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 16px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.movement-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(33, 150, 243, 0.4);
}

.movement-btn i {
    font-size: 1.1rem;
}


/* Responsive Hero */
@media (max-width: 768px) {
    .hero-section {
        padding: 60px 0;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
        gap: 16px;
    }
    
    .hero-btn {
        width: 100%;
        max-width: 280px;
    }
    
    .movement-cards {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 12px;
    }
    
    .header-content {
        padding: 12px;
    }
    
    header h1 {
        font-size: 1.2rem;
    }
    
    .hero-section {
        padding: 32px 20px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-features {
        gap: 20px;
    }
    
    .feature-item i {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
    
    .movement-buttons {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .movement-content {
        padding: 20px;
    }
    
    .movement-content h3 {
        font-size: 1.5rem;
    }
    
    .tips-grid {
        grid-template-columns: 1fr;
    }
    
    .section-header-enhanced {
        flex-direction: column;
        text-align: center;
        gap: 16px;
    }
    
    .section-title-group h1 {
        font-size: 1.8rem;
    }
    
    .formulas-grid {
        grid-template-columns: 1fr;
    }
    
    .inputs-grid {
        grid-template-columns: 1fr;
    }
    
    .results-grid {
        grid-template-columns: 1fr;
    }
    
    .history-stats {
        grid-template-columns: 1fr;
    }
    
    .history-actions {
        flex-direction: column;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .formulas-grid {
        grid-template-columns: 1fr;
    }
    
    .section-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .section-header h2 {
        font-size: 1.5rem;
        text-align: center;
    }
    
    .history-values {
        grid-template-columns: 1fr 1fr;
    }
    
    .setting-item {
        flex-direction: column;
        align-items: stretch;
        gap: 16px;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .section {
        padding: 16px 0;
    }
    
    .hero-section {
        padding: 24px 16px;
    }
    
    .hero-title {
        font-size: 1.8rem;
    }
    
    .hero-subtitle {
        font-size: 0.9rem;
    }
    
    .hero-features {
        flex-direction: column;
        gap: 16px;
    }
    
    .movement-intro h2 {
        font-size: 1.5rem;
    }
    
    .movement-intro p {
        font-size: 1rem;
    }
    
    .movement-content {
        padding: 16px;
    }
    
    .movement-content h3 {
        font-size: 1.3rem;
    }
    
    .movement-content h4 {
        font-size: 1rem;
    }
    
    .movement-content p {
        font-size: 0.9rem;
    }
    
    .movement-example {
        padding: 10px;
        font-size: 0.85rem;
    }
    
    .quick-tips {
        padding: 20px;
    }
    
    .quick-tips h3 {
        font-size: 1.1rem;
    }
    
    .tip-item {
        padding: 10px;
    }
    
    .tip-item span {
        font-size: 0.9rem;
    }
    
    .welcome-card,
    .simulation-card,
    .results-card,
    .formula-card {
        padding: 16px;
        margin-bottom: 16px;
    }
    
    .calculation-steps,
    .chart-container {
        padding: 16px;
    }
    
    .history-values {
        grid-template-columns: 1fr;
    }
    
    .nav-item span {
        font-size: 0.6rem;
    }
    
    .nav-item i {
        font-size: 1rem;
    }
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes slideIn {
    from { transform: translateX(-100%); }
    to { transform: translateX(0); }
}

.section.active {
    animation: fadeIn 0.3s ease;
}

.results-section {
    animation: slideIn 0.4s ease;
}

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading .calculate-btn {
    background: var(--text-secondary);
    cursor: not-allowed;
}

/* Error States */
.error-message {
    background: #ffebee;
    color: var(--danger-color);
    padding: 12px 16px;
    border-radius: var(--border-radius);
    margin: 16px 0;
    border-left: 4px solid var(--danger-color);
}

[data-theme="dark"] .error-message {
    background: rgba(244, 67, 54, 0.1);
    color: #ff5252;
}

/* Success States */
.success-message {
    background: #e8f5e8;
    color: var(--secondary-color);
    padding: 12px 16px;
    border-radius: var(--border-radius);
    margin: 16px 0;
    border-left: 4px solid var(--secondary-color);
}

[data-theme="dark"] .success-message {
    background: rgba(76, 175, 80, 0.1);
    color: #66bb6a;
}

/* Print Styles */
@media print {
    .bottom-nav,
    .theme-toggle,
    .back-button,
    .clear-btn,
    .danger-btn {
        display: none !important;
    }
    
    .section {
        display: block !important;
        page-break-inside: avoid;
    }
    
    .chart-container {
        page-break-inside: avoid;
    }
}