/* Reset and base styles */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --error-color: #e74c3c;
    --text-color: #333;
    --text-light: #666;
    --background-color: #f8f9fa;
    --surface-color: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.2);
    --border-radius: 8px;
    --border-radius-sm: 4px;
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Navigation - Mobile First */
.navbar {
    background: var(--secondary-color);
    color: white;
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.nav-links a {
    color: white;
    text-decoration: none;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-sm);
    transition: background-color 0.3s;
    font-weight: 500;
}

.nav-links a:hover,
.nav-links a.active {
    background-color: rgba(255, 255, 255, 0.1);
}

/* Mobile menu toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
    gap: 4px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: white;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: var(--spacing-2xl) 0;
    text-align: center;
}

.hero-content h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
    font-weight: 700;
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-xl);
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Features Section */
.features {
    padding: var(--spacing-2xl) 0;
    background: var(--surface-color);
}

.features h2 {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    font-size: 2.5rem;
    color: var(--secondary-color);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
}

.feature-card {
    background: var(--surface-color);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.feature-card h3 {
    color: var(--secondary-color);
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
}

.feature-card p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--border-radius-sm);
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
    font-size: 1rem;
    gap: var(--spacing-sm);
    text-align: center;
}

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

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-secondary {
    background: #95a5a6;
    color: white;
}

.btn-secondary:hover {
    background: #7f8c8d;
    transform: translateY(-2px);
}

.btn-full {
    width: 100%;
}

.btn-small {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.9rem;
}

/* Auth pages */
.auth-page {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.auth-container {
    width: 100%;
    max-width: 400px;
}

.auth-form {
    background: var(--surface-color);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
}

.auth-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.auth-header h2 {
    margin-bottom: var(--spacing-sm);
    color: var(--secondary-color);
}

.auth-footer {
    text-align: center;
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    color: var(--text-light);
}

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

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

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-row {
    display: flex;
    gap: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: 1rem;
    transition: border-color 0.3s, box-shadow 0.3s;
    background: var(--surface-color);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
    font-family: inherit;
}

/* Alerts */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
    margin-bottom: var(--spacing-lg);
    border: 1px solid transparent;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border-color: #f5c6cb;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border-color: #c3e6cb;
}

/* Cards */
.card {
    background: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: transform 0.3s;
}

.card:hover {
    transform: translateY(-2px);
}

/* Dashboard Styles */
.dashboard-header {
    margin: var(--spacing-xl) 0;
    text-align: center;
}

.dashboard-header h2 {
    color: var(--secondary-color);
    margin-bottom: var(--spacing-md);
}

.user-status {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
    flex-wrap: wrap;
}

.level-badge {
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: bold;
}

.watch-status {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: bold;
}

.watch-status.connected {
    background: var(--success-color);
    color: white;
}

.watch-status.disconnected {
    background: var(--error-color);
    color: white;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.stat-card {
    background: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
    margin: var(--spacing-sm) 0;
}

.stat-unit {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* Watch Data Section */
.watch-data-section {
    background: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    margin: var(--spacing-xl) 0;
    box-shadow: var(--shadow);
}

.watch-data-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-md);
}

.data-card {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    text-align: center;
}

.data-value {
    font-size: 2rem;
    font-weight: bold;
    margin: var(--spacing-sm) 0;
}

.data-unit {
    opacity: 0.9;
    font-size: 0.9rem;
}

/* Equipment Filter */
.equipment-filter {
    background: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    margin: var(--spacing-lg) 0;
}

.filter-options {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.filter-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    text-decoration: none;
    color: var(--text-color);
    transition: all 0.3s;
    font-size: 0.9rem;
}

.filter-btn.active,
.filter-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Exercises Grid */
.exercises-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.exercise-card {
    background: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: transform 0.3s;
}

.exercise-card:hover {
    transform: translateY(-2px);
}

.exercise-card.detailed {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.exercise-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-md);
}

.exercise-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.9rem;
    color: var(--text-light);
    flex-wrap: wrap;
}

.exercise-description {
    color: var(--text-light);
    line-height: 1.6;
}

.exercise-actions {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: auto;
}

/* Difficulty badges */
.difficulty-badge {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: bold;
    color: white;
}

.difficulty-badge.beginner {
    background: var(--success-color);
}

.difficulty-badge.intermediate {
    background: var(--warning-color);
}

.difficulty-badge.advanced {
    background: #e67e22;
}

.difficulty-badge.pro {
    background: var(--error-color);
}

/* Equipment badges */
.equipment {
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    font-size: 0.8rem;
    font-weight: bold;
    color: white;
}

.equipment.none {
    background: var(--success-color);
}

.equipment.basic {
    background: var(--warning-color);
}

.equipment.moderate {
    background: #e67e22;
}

.equipment.advanced {
    background: var(--error-color);
}

/* CAPTCHA */
.captcha-section {
    margin: var(--spacing-lg) 0;
}

.captcha-container {
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    text-align: center;
}

.captcha-placeholder {
    color: var(--text-light);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: var(--surface-color);
    margin: 5% auto;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 600px;
    max-height: 80vh;
    overflow-y: auto;
    position: relative;
    box-shadow: var(--shadow-lg);
}

.modal-close {
    position: absolute;
    right: var(--spacing-lg);
    top: var(--spacing-lg);
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-close:hover {
    color: var(--text-color);
}

.modal-title {
    margin-bottom: var(--spacing-lg);
    color: var(--secondary-color);
}

.modal-body {
    line-height: 1.6;
}

/* Footer */
.footer {
    background: var(--secondary-color);
    color: white;
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-2xl);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
}

.footer-links {
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.footer-links a {
    color: white;
    text-decoration: none;
    transition: opacity 0.3s;
}

.footer-links a:hover {
    opacity: 0.8;
}

/* PWA Install Prompt */
.pwa-install-prompt {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    background: var(--surface-color);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    z-index: 3000;
    max-width: 300px;
    border: 1px solid var(--border-color);
}

.pwa-prompt-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

/* Quick Actions */
.quick-actions {
    margin: var(--spacing-2xl) 0;
}

.action-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* Field errors */
.field-error {
    color: var(--error-color);
    font-size: 0.9rem;
    margin-top: var(--spacing-xs);
}

.form-group input.error,
.form-group select.error,
.form-group textarea.error {
    border-color: var(--error-color);
}

/* Loading spinner */
.loading-spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid #ffffff;
    border-radius: 50%;
    border-top-color: transparent;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Notifications */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--surface-color);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    z-index: 4000;
    max-width: 300px;
    border-left: 4px solid var(--primary-color);
}

.notification-success {
    border-left-color: var(--success-color);
}

.notification-warning {
    border-left-color: var(--warning-color);
}

.notification-error {
    border-left-color: var(--error-color);
}

.notification-content {
    display: flex;
    align-items: center;
    justify-content: between;
    gap: var(--spacing-md);
}

.notification-close {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: row;
    }
    
    .menu-toggle {
        display: flex;
    }
    
    .nav-links {
        flex-direction: column;
        width: 100%;
        display: none;
        margin-top: var(--spacing-md);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .hero-content h2 {
        font-size: 2rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .form-row {
        flex-direction: column;
        gap: var(--spacing-lg);
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .exercises-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .modal-content {
        margin: 10% auto;
        width: 95%;
        padding: var(--spacing-lg);
    }
    
    .pwa-install-prompt {
        left: var(--spacing-md);
        right: var(--spacing-md);
        max-width: none;
    }
    
    .user-status {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
    }
    
    .action-buttons {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .auth-form {
        padding: var(--spacing-lg);
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero-content h2 {
        font-size: 1.75rem;
    }
    
    .features h2 {
        font-size: 2rem;
    }
    
    .feature-card {
        padding: var(--spacing-lg);
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --shadow: 0 2px 10px rgba(0,0,0,0.3);
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* Print styles */
@media print {
    .navbar,
    .footer,
    .pwa-install-prompt {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
}