/* ============================================================
   Learning Platform - Custom Stylesheet
   ============================================================ */

/* ----------------------------------------------------------
   CSS Variables
   ---------------------------------------------------------- */
:root {
    /* Primary Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-primary-bg: #eff6ff;

    /* Accent Colors */
    --color-success: #16a34a;
    --color-warning: #f59e0b;
    --color-danger: #dc2626;
    --color-info: #0891b2;

    /* Neutral Colors */
    --color-dark: #1e293b;
    --color-gray-900: #0f172a;
    --color-gray-800: #1e293b;
    --color-gray-700: #334155;
    --color-gray-600: #475569;
    --color-gray-500: #64748b;
    --color-gray-400: #94a3b8;
    --color-gray-300: #cbd5e1;
    --color-gray-200: #e2e8f0;
    --color-gray-100: #f1f5f9;
    --color-gray-50: #f8fafc;
    --color-white: #ffffff;

    /* Typography */
    --font-ui: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-content: 'Merriweather', Georgia, 'Times New Roman', serif;

    /* Spacing */
    --section-padding: 5rem;
    --card-radius: 0.75rem;
    --btn-radius: 0.5rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --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);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* ----------------------------------------------------------
   Base / Reset
   ---------------------------------------------------------- */
*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-ui);
    color: var(--color-gray-800);
    background-color: var(--color-white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

/* ----------------------------------------------------------
   Typography
   ---------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-ui);
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-gray-900);
}

h1 { font-size: 2.25rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.375rem; }
h4 { font-size: 1.125rem; }
h5 { font-size: 1rem; }
h6 { font-size: 0.875rem; }

/* Content reading font */
.content-body,
.content-body p,
.content-body li {
    font-family: var(--font-content);
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--color-gray-700);
}

.content-body h2,
.content-body h3,
.content-body h4 {
    font-family: var(--font-ui);
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.content-body p {
    margin-bottom: 1rem;
}

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

.content-body li {
    margin-bottom: 0.5rem;
}

.content-body a {
    color: var(--color-primary);
    text-decoration: underline;
    text-underline-offset: 2px;
}

.content-body a:hover {
    color: var(--color-primary-dark);
}

.content-body strong {
    color: var(--color-gray-900);
}

/* ----------------------------------------------------------
   Reading Progress Bar
   ---------------------------------------------------------- */
.reading-progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-info));
    width: 0%;
    z-index: 9999;
    transition: width 0.1s linear;
}

/* ----------------------------------------------------------
   Navbar
   ---------------------------------------------------------- */
.navbar {
    font-family: var(--font-ui);
    z-index: 1040;
}

.navbar-brand {
    font-size: 1.35rem;
    letter-spacing: -0.5px;
}

.navbar .nav-link {
    font-weight: 500;
    font-size: 0.9rem;
    padding: 0.5rem 0.85rem !important;
    color: var(--color-gray-700);
    transition: color var(--transition-fast);
    border-radius: var(--btn-radius);
}

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

.navbar-search .form-control {
    border-radius: 2rem;
    padding-left: 1rem;
    font-size: 0.9rem;
    border-color: var(--color-gray-300);
}

.navbar-search .form-control:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.15);
}

.navbar-search .btn {
    border-radius: 2rem;
    padding-left: 1rem;
    padding-right: 1rem;
}

/* ----------------------------------------------------------
   Hero Section
   ---------------------------------------------------------- */
.hero-section {
    background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 40%, #3b82f6 70%, #60a5fa 100%);
    color: var(--color-white);
    padding: 5rem 0 4rem;
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 80%;
    height: 200%;
    background: radial-gradient(ellipse, rgba(255, 255, 255, 0.08) 0%, transparent 70%);
    pointer-events: none;
}

.hero-section::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: linear-gradient(to top, var(--color-white), transparent);
    pointer-events: none;
}

.hero-title {
    font-size: 2.75rem;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -1px;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.15rem;
    font-weight: 400;
    line-height: 1.7;
    opacity: 0.92;
    max-width: 560px;
}

.hero-search .form-control {
    border: none;
    border-radius: 0.5rem 0 0 0.5rem;
    padding: 0.85rem 1.25rem;
    font-size: 1rem;
}

.hero-search .btn {
    border-radius: 0 0.5rem 0.5rem 0;
    padding: 0.85rem 1.75rem;
    font-weight: 600;
}

.hero-quick-btn {
    border-radius: 0.75rem;
    font-weight: 500;
    padding: 0.65rem 1.25rem;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.hero-quick-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.hero-illustration {
    position: relative;
}

.hero-illustration i {
    font-size: 12rem;
    opacity: 0.15;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* ----------------------------------------------------------
   Section Styles
   ---------------------------------------------------------- */
.section-title {
    font-weight: 800;
    color: var(--color-gray-900);
    letter-spacing: -0.5px;
}

.section-subtitle {
    font-size: 1.05rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ----------------------------------------------------------
   Cards
   ---------------------------------------------------------- */
.feature-card {
    border-radius: var(--card-radius);
    transition: all var(--transition-base);
}

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

.card-hover {
    transition: all var(--transition-base);
    border-radius: var(--card-radius);
}

.card-hover:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.card-hover .card-body a {
    transition: color var(--transition-fast);
}

/* ----------------------------------------------------------
   Stats Section
   ---------------------------------------------------------- */
.stats-section {
    position: relative;
    overflow: hidden;
}

.stats-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    pointer-events: none;
}

.stat-item {
    padding: 1rem 0;
}

.stat-number {
    font-variant-numeric: tabular-nums;
}

/* ----------------------------------------------------------
   About Section
   ---------------------------------------------------------- */
.mission-card,
.vision-card {
    border-radius: var(--card-radius);
    transition: all var(--transition-base);
}

.mission-card:hover,
.vision-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* ----------------------------------------------------------
   Content Body (Notes, Blog, Legal Pages)
   ---------------------------------------------------------- */
.content-body {
    max-width: 100%;
}

.content-body img {
    max-width: 100%;
    height: auto;
    border-radius: var(--card-radius);
    margin: 1.5rem 0;
}

.content-body blockquote {
    border-left: 4px solid var(--color-primary);
    padding: 1rem 1.5rem;
    margin: 1.5rem 0;
    background-color: var(--color-primary-bg);
    border-radius: 0 var(--card-radius) var(--card-radius) 0;
    font-style: italic;
    color: var(--color-gray-700);
}

.content-body code {
    background-color: var(--color-gray-100);
    padding: 0.2rem 0.4rem;
    border-radius: 0.25rem;
    font-size: 0.9em;
    color: var(--color-danger);
}

.content-body pre {
    background-color: var(--color-gray-900);
    color: var(--color-gray-100);
    padding: 1rem 1.25rem;
    border-radius: var(--card-radius);
    overflow-x: auto;
    margin: 1.5rem 0;
}

.content-body pre code {
    background: none;
    color: inherit;
    padding: 0;
    font-size: 0.9em;
}

.content-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
}

.content-body th,
.content-body td {
    border: 1px solid var(--color-gray-300);
    padding: 0.75rem;
    text-align: left;
}

.content-body th {
    background-color: var(--color-gray-100);
    font-weight: 600;
    font-family: var(--font-ui);
}

.content-body td {
    font-size: 0.95rem;
}

/* ----------------------------------------------------------
   MCQ / Quiz Styles
   ---------------------------------------------------------- */
.quiz-container {
    max-width: 800px;
    margin: 0 auto;
}

.quiz-question {
    background: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--card-radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    transition: all var(--transition-base);
}

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

.quiz-option {
    display: flex;
    align-items: center;
    padding: 0.85rem 1rem;
    margin-bottom: 0.5rem;
    border: 2px solid var(--color-gray-200);
    border-radius: var(--btn-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
}

.quiz-option:hover {
    border-color: var(--color-primary);
    background-color: var(--color-primary-bg);
}

.quiz-option.selected {
    border-color: var(--color-primary);
    background-color: var(--color-primary-bg);
}

.quiz-option.correct {
    border-color: var(--color-success);
    background-color: rgba(22, 163, 74, 0.1);
}

.quiz-option.incorrect {
    border-color: var(--color-danger);
    background-color: rgba(220, 38, 38, 0.1);
}

.quiz-option input[type="radio"] {
    margin-right: 0.75rem;
    accent-color: var(--color-primary);
}

.quiz-timer {
    font-variant-numeric: tabular-nums;
    font-weight: 600;
    font-size: 1.1rem;
}

.quiz-timer.warning {
    color: var(--color-danger);
    animation: pulse 1s ease-in-out infinite;
}

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

.quiz-progress {
    height: 6px;
    border-radius: 3px;
    background-color: var(--color-gray-200);
    overflow: hidden;
}

.quiz-progress-bar {
    height: 100%;
    border-radius: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-info));
    transition: width var(--transition-base);
}

.quiz-result {
    text-align: center;
    padding: 2rem;
}

.quiz-result .score-circle {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.quiz-result .score-circle.excellent {
    background: rgba(22, 163, 74, 0.1);
    color: var(--color-success);
    border: 4px solid var(--color-success);
}

.quiz-result .score-circle.good {
    background: rgba(37, 99, 235, 0.1);
    color: var(--color-primary);
    border: 4px solid var(--color-primary);
}

.quiz-result .score-circle.average {
    background: rgba(245, 158, 11, 0.1);
    color: var(--color-warning);
    border: 4px solid var(--color-warning);
}

.quiz-result .score-circle.poor {
    background: rgba(220, 38, 38, 0.1);
    color: var(--color-danger);
    border: 4px solid var(--color-danger);
}

/* ----------------------------------------------------------
   Ad Container
   ---------------------------------------------------------- */
.ad-container {
    min-height: 90px;
    padding: 0.5rem;
    margin-bottom: 0.5rem;
    border-radius: var(--card-radius);
    background-color: var(--color-gray-50);
    overflow: hidden;
}

.ad-container::before {
    content: 'Advertisement';
    display: block;
    font-size: 0.7rem;
    color: var(--color-gray-400);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.25rem;
    text-align: center;
}

.ad-sidebar {
    min-height: 250px;
}

.ad-inline {
    min-height: 100px;
    margin: 1.5rem 0;
}

/* ----------------------------------------------------------
   Back to Top Button
   ---------------------------------------------------------- */
.btn-floating {
    width: 45px;
    height: 45px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    transition: all var(--transition-base);
    opacity: 0;
    transform: translateY(20px);
}

.btn-floating.visible {
    opacity: 1;
    transform: translateY(0);
}

.btn-floating:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* ----------------------------------------------------------
   Error Pages (404, 500)
   ---------------------------------------------------------- */
.min-vh-50 {
    min-height: 50vh;
}

.error-illustration {
    user-select: none;
}

/* ----------------------------------------------------------
   Breadcrumb
   ---------------------------------------------------------- */
.breadcrumb {
    font-size: 0.875rem;
}

.breadcrumb-item a {
    color: var(--color-gray-600);
    text-decoration: none;
}

.breadcrumb-item a:hover {
    color: var(--color-primary);
}

.breadcrumb-item.active {
    color: var(--color-gray-800);
    font-weight: 500;
}

/* ----------------------------------------------------------
   Badges
   ---------------------------------------------------------- */
.badge {
    font-weight: 500;
    font-size: 0.8rem;
    letter-spacing: 0.2px;
}

/* ----------------------------------------------------------
   Forms
   ---------------------------------------------------------- */
.form-control:focus,
.form-select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.15);
}

.form-label {
    font-weight: 500;
    color: var(--color-gray-700);
}

/* ----------------------------------------------------------
   Footer
   ---------------------------------------------------------- */
footer {
    font-size: 0.9rem;
}

footer a:hover {
    color: var(--color-white) !important;
    transition: color var(--transition-fast);
}

.social-links a {
    transition: all var(--transition-base);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 50%;
}

.social-links a:hover {
    background-color: var(--color-primary);
    color: var(--color-white) !important;
    transform: translateY(-2px);
}

/* ----------------------------------------------------------
   List Groups
   ---------------------------------------------------------- */
.list-group-item {
    transition: background-color var(--transition-fast);
}

.list-group-item-action:hover {
    background-color: var(--color-gray-50);
}

/* ----------------------------------------------------------
   Animation Utilities
   ---------------------------------------------------------- */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.6s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.slide-in-left {
    opacity: 0;
    transform: translateX(-30px);
    transition: all 0.6s ease-out;
}

.slide-in-left.visible {
    opacity: 1;
    transform: translateX(0);
}

.slide-in-right {
    opacity: 0;
    transform: translateX(30px);
    transition: all 0.6s ease-out;
}

.slide-in-right.visible {
    opacity: 1;
    transform: translateX(0);
}

.scale-in {
    opacity: 0;
    transform: scale(0.9);
    transition: all 0.5s ease-out;
}

.scale-in.visible {
    opacity: 1;
    transform: scale(1);
}

/* Stagger animation delays */
.stagger-1 { transition-delay: 0.1s; }
.stagger-2 { transition-delay: 0.2s; }
.stagger-3 { transition-delay: 0.3s; }
.stagger-4 { transition-delay: 0.4s; }

/* ----------------------------------------------------------
   Accessibility
   ---------------------------------------------------------- */
.sr-only-focusable:focus {
    position: static;
    width: auto;
    height: auto;
    padding: 0;
    margin: 0;
    overflow: visible;
    clip: auto;
    white-space: normal;
}

:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Skip to content link */
.skip-link {
    position: absolute;
    top: -100px;
    left: 0;
    background: var(--color-primary);
    color: var(--color-white);
    padding: 0.5rem 1rem;
    z-index: 10000;
    text-decoration: none;
    font-weight: 600;
    border-radius: 0 0 var(--btn-radius) 0;
}

.skip-link:focus {
    top: 0;
}

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

::-webkit-scrollbar-track {
    background: var(--color-gray-100);
}

::-webkit-scrollbar-thumb {
    background: var(--color-gray-400);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-gray-500);
}

/* ----------------------------------------------------------
   Selection
   ---------------------------------------------------------- */
::selection {
    background-color: rgba(37, 99, 235, 0.2);
    color: var(--color-gray-900);
}

/* ----------------------------------------------------------
   Print Styles
   ---------------------------------------------------------- */
@media print {
    .navbar,
    .hero-section,
    .ad-container,
    footer,
    #backToTop,
    .btn,
    .reading-progress-bar,
    .no-print {
        display: none !important;
    }

    body {
        font-size: 12pt;
        color: #000;
        background: #fff;
    }

    .content-body,
    .content-body p,
    .content-body li {
        font-size: 11pt;
        line-height: 1.6;
        color: #000;
    }

    h1 { font-size: 20pt; }
    h2 { font-size: 16pt; }
    h3 { font-size: 13pt; }

    a {
        color: #000;
        text-decoration: underline;
    }

    a[href]::after {
        content: " (" attr(href) ")";
        font-size: 9pt;
        font-weight: normal;
    }

    a[href^="#"]::after,
    a[href^="javascript"]::after {
        content: "";
    }

    img {
        max-width: 100% !important;
        page-break-inside: avoid;
    }

    h2, h3 {
        page-break-after: avoid;
        page-break-before: auto;
    }

    .card {
        border: 1px solid #ddd !important;
        box-shadow: none !important;
        break-inside: avoid;
    }

    @page {
        margin: 2cm;
    }
}

/* ----------------------------------------------------------
   Responsive Adjustments
   ---------------------------------------------------------- */

/* Large screens */
@media (min-width: 1400px) {
    .hero-title {
        font-size: 3.25rem;
    }
}

/* Tablets */
@media (max-width: 991.98px) {
    .hero-section {
        padding: 3rem 0 2.5rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-illustration {
        display: none;
    }

    .navbar-search {
        margin-top: 0.75rem;
        width: 100%;
    }

    .section-title {
        font-size: 1.5rem;
    }
}

/* Mobile */
@media (max-width: 767.98px) {
    .hero-section {
        padding: 2.5rem 0 2rem;
    }

    .hero-title {
        font-size: 1.75rem;
        letter-spacing: -0.5px;
    }

    .hero-subtitle {
        font-size: 0.95rem;
    }

    .hero-search .input-group {
        flex-direction: column;
    }

    .hero-search .form-control,
    .hero-search .btn {
        border-radius: 0.5rem;
        width: 100%;
    }

    .hero-search .btn {
        margin-top: 0.5rem;
    }

    .hero-quick-links {
        justify-content: center;
    }

    .hero-quick-btn {
        font-size: 0.85rem;
        padding: 0.5rem 1rem;
    }

    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.35rem;
    }

    h3 {
        font-size: 1.15rem;
    }

    .content-body,
    .content-body p {
        font-size: 0.95rem;
    }

    .stat-item {
        padding: 0.5rem 0;
    }

    .btn-floating {
        width: 40px;
        height: 40px;
        bottom: 1rem !important;
        right: 1rem !important;
    }
}

/* Small mobile */
@media (max-width: 575.98px) {
    .hero-title {
        font-size: 1.5rem;
    }

    .container {
        padding-left: 1rem;
        padding-right: 1rem;
    }

    .card-body {
        padding: 1rem;
    }

    .feature-icon {
        width: 56px !important;
        height: 56px !important;
    }

    .feature-icon i {
        font-size: 1.25rem !important;
    }
}