/**
 * KTT LMS Theme CSS
 * =================
 * Core theme styles, CSS variables, and common components
 * Shared across all lectures and pages
 */

/* ============================================
   CSS VARIABLES FOR THEMING
   ============================================ */
:root {
    /* Brand Colors */
    --brand-primary: #6366f1;
    --brand-secondary: #8b5cf6;
    --brand-accent: #06b6d4;
    --brand-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #06b6d4 100%);
    --brand-gradient-soft: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);

    /* Light Theme */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-glass: rgba(255, 255, 255, 0.7);
    --bg-card: #ffffff;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --text-light: #94a3b8;

    --border-color: #e2e8f0;
    --border-light: rgba(0, 0, 0, 0.05);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);

    /* Status Colors */
    --success: #10b981;
    --success-bg: rgba(16, 185, 129, 0.1);
    --warning: #f59e0b;
    --warning-bg: rgba(245, 158, 11, 0.1);
    --info: #3b82f6;
    --info-bg: rgba(59, 130, 246, 0.1);
    --error: #ef4444;
    --error-bg: rgba(239, 68, 68, 0.1);

    /* Layout */
    --max-width: 820px;
    --nav-height: 70px;
    --side-nav-width: 280px;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-slow: 0.4s ease;

    /* Quiz specific (for quiz-system.js) */
    --accent: var(--brand-primary);
    --accent-light: var(--brand-gradient-soft);
    --accent-dark: #4f46e5;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-glass: rgba(15, 23, 42, 0.8);
    --bg-card: #1e293b;

    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --text-light: #64748b;

    --border-color: #334155;
    --border-light: rgba(255, 255, 255, 0.05);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.25);
}

/* ============================================
   GOOGLE FONTS IMPORT
   ============================================ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

/* ============================================
   RESET & BASE
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--nav-height) + 24px);
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    color: var(--text-primary);
    background: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    transition: background var(--transition-normal), color var(--transition-normal);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 { font-size: 2.75rem; font-weight: 800; }
h2 { font-size: 1.75rem; margin-bottom: 1rem; }
h3 { font-size: 1.25rem; margin-bottom: 0.75rem; }
h4 { font-size: 1.1rem; margin-bottom: 0.5rem; }

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

a {
    color: var(--brand-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--brand-secondary);
}

ul, ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background: var(--bg-tertiary);
    padding: 0.2em 0.4em;
    border-radius: 4px;
    color: var(--brand-primary);
}

pre {
    font-family: var(--font-mono);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    overflow-x: auto;
    margin-bottom: 1rem;
}

pre code {
    background: transparent;
    padding: 0;
    color: inherit;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.85rem 1.5rem;
    border-radius: 12px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    text-decoration: none;
}

.btn-primary {
    background: var(--brand-gradient);
    color: white;
    box-shadow: var(--shadow-md);
}

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

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.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(--brand-primary);
    color: var(--brand-primary);
}

.btn-text {
    background: transparent;
    color: var(--text-secondary);
    padding: 0.5rem 1rem;
}

.btn-text:hover {
    color: var(--brand-primary);
    background: var(--brand-gradient-soft);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    border-radius: 8px;
}

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

.btn-danger:hover {
    background: #dc2626;
}

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

.btn-success:hover {
    background: #059669;
}

/* ============================================
   FORM ELEMENTS
   ============================================ */
input, textarea, select {
    font-family: var(--font-sans);
    font-size: 1rem;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    background: var(--bg-card);
    color: var(--text-primary);
    transition: all var(--transition-fast);
    width: 100%;
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--brand-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

input::placeholder, textarea::placeholder {
    color: var(--text-muted);
}

label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

/* ============================================
   CARDS
   ============================================ */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 1.5rem;
    transition: all var(--transition-fast);
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.card-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

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

/* ============================================
   BADGES & TAGS
   ============================================ */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 20px;
    background: var(--brand-gradient-soft);
    color: var(--brand-primary);
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.badge-success {
    background: var(--success-bg);
    color: var(--success);
    border-color: rgba(16, 185, 129, 0.2);
}

.badge-warning {
    background: var(--warning-bg);
    color: var(--warning);
    border-color: rgba(245, 158, 11, 0.2);
}

.badge-error {
    background: var(--error-bg);
    color: var(--error);
    border-color: rgba(239, 68, 68, 0.2);
}

.badge-info {
    background: var(--info-bg);
    color: var(--info);
    border-color: rgba(59, 130, 246, 0.2);
}

.tag {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    font-size: 0.7rem;
    font-weight: 500;
    border-radius: 6px;
    background: var(--bg-tertiary);
    color: var(--text-muted);
}

/* ============================================
   CALLOUT BOXES
   ============================================ */
.callout {
    padding: 1.25rem 1.5rem;
    border-radius: 14px;
    margin: 1.5rem 0;
    border: 1px solid;
    position: relative;
    overflow: hidden;
}

.callout::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
}

.callout-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
}

.callout-icon {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
}

.callout-title {
    font-weight: 600;
    font-size: 0.9rem;
}

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

/* Callout Types */
.callout-definition {
    background: var(--info-bg);
    border-color: rgba(59, 130, 246, 0.3);
}
.callout-definition::before { background: var(--info); }
.callout-definition .callout-icon { background: var(--info); color: white; }
.callout-definition .callout-title { color: var(--info); }

.callout-important {
    background: var(--warning-bg);
    border-color: rgba(245, 158, 11, 0.3);
}
.callout-important::before { background: var(--warning); }
.callout-important .callout-icon { background: var(--warning); color: white; }
.callout-important .callout-title { color: var(--warning); }

.callout-analogy {
    background: var(--brand-gradient-soft);
    border-color: rgba(99, 102, 241, 0.3);
}
.callout-analogy::before { background: var(--brand-primary); }
.callout-analogy .callout-icon { background: var(--brand-primary); color: white; }
.callout-analogy .callout-title { color: var(--brand-primary); }

.callout-success {
    background: var(--success-bg);
    border-color: rgba(16, 185, 129, 0.3);
}
.callout-success::before { background: var(--success); }
.callout-success .callout-icon { background: var(--success); color: white; }
.callout-success .callout-title { color: var(--success); }

/* ============================================
   LOADING STATES
   ============================================ */
.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--brand-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

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

.skeleton {
    background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--bg-secondary) 50%, var(--bg-tertiary) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: 8px;
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--text-primary) !important; }
.text-secondary { color: var(--text-secondary) !important; }
.text-muted { color: var(--text-muted) !important; }
.text-brand { color: var(--brand-primary) !important; }
.text-success { color: var(--success) !important; }
.text-warning { color: var(--warning) !important; }
.text-error { color: var(--error) !important; }

.bg-primary { background: var(--bg-primary); }
.bg-secondary { background: var(--bg-secondary); }
.bg-tertiary { background: var(--bg-tertiary); }
.bg-card { background: var(--bg-card); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: 0.25rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 0.75rem; }
.gap-4 { gap: 1rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 0.75rem; }
.p-4 { padding: 1rem; }
.p-6 { padding: 1.5rem; }

.m-0 { margin: 0; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-4 { margin-top: 1rem; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-4 { margin-bottom: 1rem; }

.rounded { border-radius: 8px; }
.rounded-lg { border-radius: 12px; }
.rounded-xl { border-radius: 16px; }
.rounded-full { border-radius: 9999px; }

.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }

.hidden { display: none !important; }
.visible { visibility: visible; }
.invisible { visibility: hidden; }

.w-full { width: 100%; }
.h-full { height: 100%; }

.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }

.cursor-pointer { cursor: pointer; }
.select-none { user-select: none; }

/* ============================================
   GRID SYSTEM
   ============================================ */
.grid {
    display: grid;
    gap: 1rem;
}

.grid-cols-1 { grid-template-columns: repeat(1, 1fr); }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 768px) {
    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: repeat(1, 1fr);
    }
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.animate-fadeIn {
    animation: fadeIn 0.3s ease;
}

.animate-slideUp {
    animation: slideUp 0.4s ease;
}

/* ============================================
   RESPONSIVE BREAKPOINTS
   ============================================ */
@media (max-width: 1024px) {
    :root {
        --side-nav-width: 260px;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }
}

@media (max-width: 768px) {
    :root {
        --nav-height: 60px;
    }

    body {
        font-size: 15px;
    }

    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.35rem; }
    h3 { font-size: 1.1rem; }

    .btn {
        padding: 0.75rem 1.25rem;
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    h1 { font-size: 1.5rem; }

    .card {
        padding: 1rem;
    }
}

/* ============================================
   PRINT STYLES
   ============================================ */
@media print {
    :root {
        --bg-primary: #ffffff;
        --text-primary: #000000;
    }

    body {
        background: white;
        color: black;
    }

    .side-nav,
    .top-nav,
    .btn,
    .quick-actions {
        display: none !important;
    }

    .main-content {
        margin: 0;
        padding: 0;
    }
}