/**
 * TAO Academy - Modern Flat Design System
 * Bootstrap 5 Inspired | Minimalistic | Cutting-Edge UX
 * Focus: Maximum Connectivity & Learning Outcomes
 */

/* ==========================================
   1. DESIGN TOKENS (Modern Flat Palette)
   ========================================== */

:root {
    /* Primary Colors - Vibrant & Modern */
    --primary-50: #f0f4ff;
    --primary-100: #dbe4ff;
    --primary-200: #bac8ff;
    --primary-300: #91a7ff;
    --primary-400: #748ffc;
    --primary-500: #5c7cfa;  /* Main primary */
    --primary-600: #4c6ef5;
    --primary-700: #4263eb;
    --primary-800: #3b5bdb;
    --primary-900: #364fc7;

    /* Accent Colors - High Contrast */
    --accent-purple: #7950f2;
    --accent-pink: #ff6b9d;
    --accent-teal: #12b886;
    --accent-orange: #fd7e14;

    /* Success/Warning/Error - Flat */
    --success: #20c997;
    --warning: #ffc107;
    --error: #fa5252;
    --info: #228be6;

    /* Neutrals - Clean & Minimal */
    --neutral-50: #f8f9fa;
    --neutral-100: #f1f3f5;
    --neutral-200: #e9ecef;
    --neutral-300: #dee2e6;
    --neutral-400: #ced4da;
    --neutral-500: #adb5bd;
    --neutral-600: #868e96;
    --neutral-700: #495057;
    --neutral-800: #343a40;
    --neutral-900: #212529;

    /* Semantic Colors */
    --background: #ffffff;
    --surface: #f8f9fa;
    --surface-hover: #f1f3f5;
    --border: #dee2e6;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-muted: #adb5bd;

    /* Shadows - Soft & Elevated */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

    /* Spacing Scale (8px base) */
    --space-1: 0.25rem;  /* 4px */
    --space-2: 0.5rem;   /* 8px */
    --space-3: 0.75rem;  /* 12px */
    --space-4: 1rem;     /* 16px */
    --space-5: 1.25rem;  /* 20px */
    --space-6: 1.5rem;   /* 24px */
    --space-8: 2rem;     /* 32px */
    --space-10: 2.5rem;  /* 40px */
    --space-12: 3rem;    /* 48px */
    --space-16: 4rem;    /* 64px */
    --space-20: 5rem;    /* 80px */

    /* Border Radius - Consistent */
    --radius-sm: 0.375rem;  /* 6px */
    --radius-md: 0.5rem;    /* 8px */
    --radius-lg: 0.75rem;   /* 12px */
    --radius-xl: 1rem;      /* 16px */
    --radius-2xl: 1.5rem;   /* 24px */
    --radius-full: 9999px;

    /* Typography Scale */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', sans-serif;
    --font-mono: 'SF Mono', 'Monaco', 'Inconsolata', monospace;

    --text-xs: 0.75rem;     /* 12px */
    --text-sm: 0.875rem;    /* 14px */
    --text-base: 1rem;      /* 16px */
    --text-lg: 1.125rem;    /* 18px */
    --text-xl: 1.25rem;     /* 20px */
    --text-2xl: 1.5rem;     /* 24px */
    --text-3xl: 1.875rem;   /* 30px */
    --text-4xl: 2.25rem;    /* 36px */
    --text-5xl: 3rem;       /* 48px */

    /* Font Weights */
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Z-Index Scale */
    --z-base: 0;
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* Dark Mode Support */
[data-theme="dark"] {
    --background: #1a1a1a;
    --surface: #242424;
    --surface-hover: #2d2d2d;
    --border: #404040;
    --text-primary: #f8f9fa;
    --text-secondary: #ced4da;
    --text-muted: #868e96;
}

/* ==========================================
   2. RESET & BASE STYLES
   ========================================== */

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    font-weight: var(--font-normal);
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--background);
}

/* ==========================================
   3. LAYOUT SYSTEM (Modern Grid)
   ========================================== */

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.container-fluid {
    width: 100%;
    padding: 0 var(--space-4);
}

.container-narrow {
    max-width: 800px;
}

.container-wide {
    max-width: 1600px;
}

/* Modern Grid System */
.grid {
    display: grid;
    gap: var(--space-6);
}

.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }
.grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid-cols-6 { grid-template-columns: repeat(6, minmax(0, 1fr)); }
.grid-cols-12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

/* Auto-fit responsive grid */
.grid-auto-fit {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-auto-fill {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* Flex Utilities */
.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.flex-wrap {
    flex-wrap: wrap;
}

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

.items-start {
    align-items: flex-start;
}

.items-end {
    align-items: flex-end;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.justify-end {
    justify-content: flex-end;
}

.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* ==========================================
   4. MODERN CARD COMPONENTS
   ========================================== */

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    transition: all var(--transition-base);
}

.card-hover:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-300);
}

.card-interactive {
    cursor: pointer;
    transition: all var(--transition-fast);
}

.card-interactive:hover {
    background: var(--surface-hover);
}

.card-interactive:active {
    transform: scale(0.98);
}

/* Glassmorphism Card */
.card-glass {
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: var(--shadow-md);
}

/* Elevated Card */
.card-elevated {
    box-shadow: var(--shadow-lg);
    border: none;
}

/* Card Sections */
.card-header {
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--border);
    margin-bottom: var(--space-4);
}

.card-footer {
    padding-top: var(--space-4);
    border-top: 1px solid var(--border);
    margin-top: var(--space-4);
}

/* ==========================================
   5. BUTTONS (Flat & Modern)
   ========================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-size: var(--text-base);
    font-weight: var(--font-medium);
    line-height: 1;
    text-decoration: none;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

/* Primary Button */
.btn-primary {
    background: var(--primary-500);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-600);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

/* Secondary Button */
.btn-secondary {
    background: var(--neutral-100);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: var(--neutral-200);
}

/* Outline Button */
.btn-outline {
    background: transparent;
    color: var(--primary-500);
    border: 2px solid var(--primary-500);
}

.btn-outline:hover {
    background: var(--primary-50);
}

/* Ghost Button */
.btn-ghost {
    background: transparent;
    color: var(--text-primary);
}

.btn-ghost:hover {
    background: var(--neutral-100);
}

/* Icon Button */
.btn-icon {
    padding: var(--space-3);
    aspect-ratio: 1;
}

/* Button Sizes */
.btn-sm {
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-sm);
}

.btn-lg {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-lg);
}

.btn-xl {
    padding: var(--space-5) var(--space-10);
    font-size: var(--text-xl);
}

/* Button States */
.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

.btn-loading {
    position: relative;
    color: transparent;
}

.btn-loading::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    border: 2px solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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

/* ==========================================
   6. BADGES & TAGS
   ========================================== */

.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    line-height: 1;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-primary {
    background: var(--primary-100);
    color: var(--primary-700);
}

.badge-success {
    background: rgba(32, 201, 151, 0.1);
    color: #0ca678;
}

.badge-warning {
    background: rgba(255, 193, 7, 0.1);
    color: #e67700;
}

.badge-error {
    background: rgba(250, 82, 82, 0.1);
    color: #e03131;
}

.badge-dot {
    padding-left: var(--space-1);
}

.badge-dot::before {
    content: '';
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: currentColor;
}

/* ==========================================
   7. FORMS (Modern & Clean)
   ========================================== */

.form-group {
    margin-bottom: var(--space-6);
}

.form-label {
    display: block;
    margin-bottom: var(--space-2);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--text-primary);
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-base);
    font-family: inherit;
    color: var(--text-primary);
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px rgba(92, 124, 250, 0.1);
}

.form-input:disabled,
.form-select:disabled,
.form-textarea:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    background: var(--neutral-100);
}

.form-textarea {
    min-height: 120px;
    resize: vertical;
}

.form-hint {
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--text-muted);
}

.form-error {
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--error);
}

/* Checkbox & Radio (Modern) */
.form-check {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.form-check-input {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.form-check-input:checked {
    background: var(--primary-500);
    border-color: var(--primary-500);
}

/* ==========================================
   8. AVATARS & PROFILES
   ========================================== */

.avatar {
    display: inline-block;
    position: relative;
    border-radius: 50%;
    overflow: hidden;
    background: var(--neutral-200);
}

.avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.avatar-xs { width: 24px; height: 24px; }
.avatar-sm { width: 32px; height: 32px; }
.avatar-md { width: 40px; height: 40px; }
.avatar-lg { width: 64px; height: 64px; }
.avatar-xl { width: 96px; height: 96px; }

.avatar-status {
    position: absolute;
    bottom: 2px;
    right: 2px;
    width: 12px;
    height: 12px;
    border: 2px solid var(--background);
    border-radius: 50%;
}

.avatar-status-online { background: var(--success); }
.avatar-status-offline { background: var(--neutral-400); }
.avatar-status-busy { background: var(--error); }

.avatar-group {
    display: flex;
    flex-direction: row-reverse;
}

.avatar-group .avatar {
    margin-right: -12px;
    border: 2px solid var(--background);
}

.avatar-group .avatar:hover {
    z-index: 1;
    transform: scale(1.1);
}

/* ==========================================
   9. PROGRESS & INDICATORS
   ========================================== */

.progress {
    width: 100%;
    height: 8px;
    background: var(--neutral-200);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: var(--primary-500);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
}

.progress-bar-animated {
    background: linear-gradient(90deg,
        var(--primary-500) 0%,
        var(--primary-400) 50%,
        var(--primary-500) 100%
    );
    background-size: 200% 100%;
    animation: progress-animation 2s ease-in-out infinite;
}

@keyframes progress-animation {
    0% { background-position: 100% 0; }
    100% { background-position: -100% 0; }
}

/* Spinner */
.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--neutral-200);
    border-top-color: var(--primary-500);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

.spinner-sm { width: 20px; height: 20px; border-width: 2px; }
.spinner-lg { width: 60px; height: 60px; border-width: 4px; }

/* ==========================================
   10. ALERTS & NOTIFICATIONS
   ========================================== */

.alert {
    padding: var(--space-4);
    border-radius: var(--radius-md);
    border-left: 4px solid;
}

.alert-info {
    background: rgba(34, 139, 230, 0.1);
    border-color: var(--info);
    color: #1971c2;
}

.alert-success {
    background: rgba(32, 201, 151, 0.1);
    border-color: var(--success);
    color: #0ca678;
}

.alert-warning {
    background: rgba(255, 193, 7, 0.1);
    border-color: var(--warning);
    color: #e67700;
}

.alert-error {
    background: rgba(250, 82, 82, 0.1);
    border-color: var(--error);
    color: #e03131;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    padding: var(--space-4) var(--space-6);
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    z-index: var(--z-toast);
    animation: slide-up 0.3s ease-out;
}

@keyframes slide-up {
    from {
        transform: translateY(100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* ==========================================
   11. UTILITY CLASSES
   ========================================== */

/* Spacing */
.m-0 { margin: 0; }
.m-auto { margin: auto; }
.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }
.p-8 { padding: var(--space-8); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.py-8 { padding-top: var(--space-8); padding-bottom: var(--space-8); }
.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.px-6 { padding-left: var(--space-6); padding-right: var(--space-6); }

/* Text */
.text-xs { font-size: var(--text-xs); }
.text-sm { font-size: var(--text-sm); }
.text-lg { font-size: var(--text-lg); }
.text-xl { font-size: var(--text-xl); }
.text-2xl { font-size: var(--text-2xl); }
.text-3xl { font-size: var(--text-3xl); }

.font-medium { font-weight: var(--font-medium); }
.font-semibold { font-weight: var(--font-semibold); }
.font-bold { font-weight: var(--font-bold); }

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

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

/* Backgrounds */
.bg-surface { background: var(--surface); }
.bg-primary { background: var(--primary-500); color: white; }
.bg-gradient {
    background: linear-gradient(135deg, var(--primary-500) 0%, var(--accent-purple) 100%);
    color: white;
}

/* Borders */
.border { border: 1px solid var(--border); }
.border-t { border-top: 1px solid var(--border); }
.border-b { border-bottom: 1px solid var(--border); }

.rounded { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-xl { border-radius: var(--radius-xl); }
.rounded-full { border-radius: var(--radius-full); }

/* Shadows */
.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }
.shadow-xl { box-shadow: var(--shadow-xl); }

/* Display */
.block { display: block; }
.inline-block { display: inline-block; }
.hidden { display: none; }

/* Width */
.w-full { width: 100%; }
.w-auto { width: auto; }

/* ==========================================
   12. RESPONSIVE DESIGN
   ========================================== */

@media (max-width: 768px) {
    .container {
        padding: 0 var(--space-4);
    }

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

    .card {
        padding: var(--space-4);
    }

    .btn-lg {
        padding: var(--space-3) var(--space-6);
        font-size: var(--text-base);
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}