/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary-color: #00d4ff;
    --primary-dark: #0099cc;
    --secondary-color: #ff6b35;
    --accent-color: #7c3aed;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    
    /* Dark Theme */
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --bg-card: #1e1e1e;
    --bg-glass: rgba(255, 255, 255, 0.05);
    
    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --text-muted: #666666;
    
    /* Borders */
    --border-color: #333333;
    --border-light: #444444;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(0, 212, 255, 0.3);
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
    --z-toast: 1080;
}

body {
    font-family: var(--font-family);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: var(--radius-md);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity var(--transition-slow), visibility var(--transition-slow);
}

.loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
}

.loading-animation {
    position: relative;
    width: 120px;
    height: 120px;
    margin-bottom: var(--spacing-xl);
}

.pulse-ring {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    border: 2px solid var(--primary-color);
    border-radius: 50%;
    animation: pulse 2s cubic-bezier(0.455, 0.03, 0.515, 0.955) infinite;
}

.pulse-ring:nth-child(2) {
    animation-delay: 0.5s;
}

.pulse-ring:nth-child(3) {
    animation-delay: 1s;
}

.logo-container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: white;
    box-shadow: var(--shadow-glow);
}

.loading-screen h2 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.loading-screen p {
    color: var(--text-secondary);
    font-size: var(--font-size-lg);
}

/* Navigation */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 70px;
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: var(--z-fixed);
    transition: transform var(--transition-normal);
}

.main-nav.hidden {
    transform: translateY(-100%);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-color);
}

.nav-brand i {
    font-size: 24px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--primary-color);
    background: var(--bg-glass);
}

.nav-link.active {
    color: var(--primary-color);
    background: rgba(0, 212, 255, 0.1);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 2px;
    background: var(--primary-color);
    border-radius: 1px;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.icon-btn {
    position: relative;
    width: 40px;
    height: 40px;
    border: none;
    background: var(--bg-glass);
    color: var(--text-secondary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.icon-btn:hover {
    background: var(--bg-tertiary);
    color: var(--primary-color);
    transform: translateY(-1px);
}

.notification-badge {
    position: absolute;
    top: -2px;
    right: -2px;
    width: 18px;
    height: 18px;
    background: var(--error-color);
    color: white;
    border-radius: 50%;
    font-size: var(--font-size-xs);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

/* Main Content */
.main-content {
    margin-top: 70px;
    min-height: calc(100vh - 70px);
    transition: opacity var(--transition-normal);
}

.main-content.hidden {
    opacity: 0;
}

/* Pages */
.page {
    display: none;
    padding: var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
}

.page.active {
    display: block;
}

.page-header {
    margin-bottom: var(--spacing-2xl);
    text-align: center;
}

.page-header h1 {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-header p {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Login Page */
.login-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: calc(100vh - 70px);
    padding: var(--spacing-xl);
}

.login-card {
    width: 100%;
    max-width: 400px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-xl);
    position: relative;
    overflow: hidden;
}

.login-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
}

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

.login-header .logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.login-header .logo i {
    font-size: 32px;
    color: var(--primary-color);
}

.login-header h1 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--primary-color);
}

.login-header p {
    color: var(--text-secondary);
    margin-top: var(--spacing-sm);
}

.login-tabs {
    display: flex;
    margin-bottom: var(--spacing-xl);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 4px;
}

.tab-btn {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-weight: 500;
}

.tab-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-sm);
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

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

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

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

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    color: var(--text-primary);
    font-size: var(--font-size-base);
    transition: all var(--transition-fast);
}

.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(0, 212, 255, 0.1);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left var(--transition-normal);
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: white;
    box-shadow: var(--shadow-md);
}

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

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

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

.btn-secondary:hover {
    background: var(--bg-card);
    border-color: var(--border-light);
}

.forgot-password {
    display: block;
    text-align: center;
    margin-top: var(--spacing-md);
    color: var(--primary-color);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: color var(--transition-fast);
}

.forgot-password:hover {
    color: var(--primary-dark);
}

/* Dashboard */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.stats-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.stats-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

.stats-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.stat-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: white;
    box-shadow: var(--shadow-glow);
}

.stat-info h3 {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.stat-info p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.dashboard-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
}

.quick-actions h2,
.recent-workouts h2 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

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

.action-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    color: var(--text-primary);
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.action-btn:hover {
    background: var(--bg-tertiary);
    border-color: var(--primary-color);
    transform: translateX(4px);
}

.action-btn i {
    font-size: 20px;
    color: var(--primary-color);
}

/* Utility Classes */
.hidden {
    display: none !important;
}

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

.text-primary {
    color: var(--primary-color);
}

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

.text-muted {
    color: var(--text-muted);
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

/* Animations */
@keyframes pulse {
    0% {
        transform: translate(-50%, -50%) scale(0.8);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(1.2);
        opacity: 0;
    }
}

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

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Responsive Design */
@media (max-width: 1024px) {
    .nav-menu {
        display: none;
    }
    
    .dashboard-content {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .page {
        padding: var(--spacing-lg);
    }
    
    .nav-container {
        padding: 0 var(--spacing-md);
    }
    
    .login-container {
        padding: var(--spacing-md);
    }
    
    .login-card {
        padding: var(--spacing-xl);
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .page-header h1 {
        font-size: var(--font-size-3xl);
    }
}

@media (max-width: 480px) {
    .main-content {
        margin-bottom: 80px;
    }
    
    .stats-card {
        padding: var(--spacing-lg);
    }
    
    .stat-icon {
        width: 50px;
        height: 50px;
        font-size: 20px;
    }
    
    .stat-info h3 {
        font-size: var(--font-size-2xl);
    }
}