/* ============================================
   STUDY TRACKER - STUDY GAMER AESTHETIC
   ============================================ */

:root {
    /* Primary Colors - Energetic Blue/Teal */
    --color-primary: #00D9FF;
    --color-primary-dark: #00A8CC;
    --color-primary-light: #66E6FF;
    
    /* Accent Colors */
    --color-accent: #FF3D71;
    --color-success: #00E676;
    --color-warning: #FFD93D;
    --color-rank: #9D4EDD;
    
    /* Background - Light Theme */
    --bg-primary: #F8F9FE;
    --bg-secondary: #FFFFFF;
    --bg-tertiary: #E8ECFF;
    --bg-overlay: rgba(0, 0, 0, 0.05);
    
    /* Text - Light Theme */
    --text-primary: #1A1D3F;
    --text-secondary: #6B7280;
    --text-muted: #9CA3AF;
    
    /* Borders & Shadows */
    --border-color: #E5E7EB;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --shadow-glow: 0 0 20px rgba(0, 217, 255, 0.3);
    
    /* Typography */
    --font-display: 'Rajdhani', sans-serif;
    --font-body: 'Work Sans', sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

[data-theme="dark"] {
    --bg-primary: #0F1117;
    --bg-secondary: #1A1D2E;
    --bg-tertiary: #252938;
    --bg-overlay: rgba(255, 255, 255, 0.05);
    
    --text-primary: #F8F9FE;
    --text-secondary: #C5C8D6;
    --text-muted: #8B8FA3;
    
    --border-color: #2D3142;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */

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

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

body {
    font-family: var(--font-body);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background 0.3s ease, color 0.3s ease;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all var(--transition-base);
}

button {
    font-family: inherit;
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
}

input, textarea, select {
    font-family: inherit;
    border: 2px solid var(--border-color);
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: all var(--transition-base);
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--color-primary);
}

/* ============================================
   LOGIN PAGE
   ============================================ */

.login-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667EEA 0%, #764BA2 100%);
    position: relative;
    overflow: hidden;
}

.login-page::before {
    content: '';
    position: absolute;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 20% 50%, rgba(0, 217, 255, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 80% 50%, rgba(255, 61, 113, 0.1) 0%, transparent 50%);
    animation: rotate 30s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.login-container {
    display: flex;
    width: 90%;
    max-width: 1200px;
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    position: relative;
    z-index: 1;
}

.login-left {
    flex: 1;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    padding: var(--spacing-xl);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.login-left::before {
    content: '';
    position: absolute;
    width: 300px;
    height: 300px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    top: -100px;
    right: -100px;
}

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

.logo-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: var(--spacing-md);
}

.logo-icon {
    width: 60px;
    height: 60px;
    color: white;
    filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.2));
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.brand-name {
    font-size: 3rem;
    color: white;
    letter-spacing: 0.05em;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.brand-name span {
    color: rgba(255, 255, 255, 0.7);
}

.brand-tagline {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    margin-top: var(--spacing-sm);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
    width: 100%;
    max-width: 400px;
}

.feature-item {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: all var(--transition-base);
}

.feature-item:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-4px);
}

.feature-icon {
    font-size: 1.5rem;
}

.feature-text {
    color: white;
    font-size: 0.9rem;
    font-weight: 500;
}

.login-right {
    flex: 1;
    padding: var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: center;
}

.login-box {
    width: 100%;
    max-width: 400px;
}

.login-title {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-xs);
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.login-subtitle {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

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

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.form-group input {
    width: 100%;
    padding: 1rem;
    border-radius: var(--radius-md);
    font-size: 1rem;
}

.btn-primary {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

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

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary.loading {
    pointer-events: none;
}

.btn-primary.loading .btn-text {
    opacity: 0;
}

.btn-primary.loading .btn-loader {
    opacity: 1;
}

.btn-loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    opacity: 0;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

.error-message {
    color: var(--color-accent);
    font-size: 0.9rem;
    margin-top: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: rgba(255, 61, 113, 0.1);
    border-radius: var(--radius-sm);
    display: none;
}

.error-message.show {
    display: block;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.login-footer {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-color);
}

.demo-credentials {
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* ============================================
   APP LAYOUT
   ============================================ */

.app-container {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 260px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    left: 0;
    top: 0;
    height: 100vh;
    z-index: 100;
    transition: transform var(--transition-base);
}

.sidebar-header {
    padding: var(--spacing-lg) var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
}

.logo-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    width: 32px;
    height: 32px;
    color: var(--color-primary);
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 0.02em;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-text span {
    opacity: 0.7;
}

.sidebar-nav {
    flex: 1;
    padding: var(--spacing-md);
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.875rem var(--spacing-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-xs);
    color: var(--text-secondary);
    font-weight: 500;
    transition: all var(--transition-base);
}

.nav-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transform: translateX(4px);
}

.nav-item.active {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    box-shadow: var(--shadow-glow);
}

.nav-icon {
    font-size: 1.25rem;
}

.sidebar-footer {
    padding: var(--spacing-md);
    border-top: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
}

.theme-toggle:hover {
    background: var(--bg-overlay);
    transform: scale(1.05);
}

.theme-icon {
    font-size: 1.25rem;
}

.btn-logout {
    width: 100%;
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-radius: var(--radius-md);
    font-weight: 500;
}

.btn-logout:hover {
    background: var(--color-accent);
    color: white;
}

.main-content {
    flex: 1;
    margin-left: 260px;
    min-height: 100vh;
}

.top-bar {
    height: 70px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 0 var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 50;
}

.menu-toggle {
    display: none;
    background: none;
    font-size: 1.5rem;
    color: var(--text-primary);
}

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

.user-name {
    font-weight: 600;
    color: var(--text-primary);
}

.user-avatar {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 1rem;
}

.content-wrapper {
    padding: var(--spacing-lg);
    max-width: 1400px;
    margin: 0 auto;
}

.page-header {
    margin-bottom: var(--spacing-lg);
}

.page-title {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-xs);
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ============================================
   STATS CARDS
   ============================================ */

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.stat-card {
    background: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    position: relative;
    overflow: hidden;
    transition: all var(--transition-base);
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--color-primary);
    transition: width var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-card:hover::before {
    width: 8px;
}

.stat-card.stat-primary::before { background: var(--color-primary); }
.stat-card.stat-success::before { background: var(--color-success); }
.stat-card.stat-warning::before { background: var(--color-warning); }
.stat-card.stat-rank::before { background: var(--color-rank); }

.stat-icon {
    font-size: 2.5rem;
    opacity: 0.8;
}

.stat-content {
    flex: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    font-family: var(--font-display);
    color: var(--text-primary);
}

.stat-change {
    font-size: 0.875rem;
    font-weight: 600;
    margin-top: 0.25rem;
}

.stat-change.positive { color: var(--color-success); }
.stat-change.negative { color: var(--color-accent); }

.stat-meta {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* ============================================
   CHARTS
   ============================================ */

.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.chart-card {
    background: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
}

.chart-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.chart-total {
    color: var(--color-primary);
    font-weight: 600;
}

/* ============================================
   ACTIVITY SECTION
   ============================================ */

.activity-section {
    background: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
}

.section-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.section-link {
    color: var(--color-primary);
    font-weight: 500;
    font-size: 0.9rem;
}

.section-link:hover {
    text-decoration: underline;
}

.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--text-muted);
}

.empty-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

.btn-secondary {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-radius: var(--radius-md);
    font-weight: 500;
    margin-top: var(--spacing-md);
}

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

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 768px) {
    .login-container {
        flex-direction: column;
        width: 95%;
    }
    
    .login-left {
        padding: var(--spacing-lg);
    }
    
    .brand-name {
        font-size: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        transform: translateX(-100%);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .menu-toggle {
        display: block;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   UTILITIES
   ============================================ */

.admin-only {
    display: none;
}

body.admin .admin-only {
    display: flex;
}

.hidden {
    display: none !important;
}

.loading {
    pointer-events: none;
    opacity: 0.6;
}