/* ==========================================================================
   CSS Variables & Design Tokens
   ========================================================================== */
:root {
    /* Fonts */
    --font-heading: 'Outfit', 'Noto Sans', sans-serif;
    --font-body: 'Noto Sans', sans-serif;
    --font-mono: 'Fira Code', monospace;

    /* Common Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-medium: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

    /* Layout values */
    --header-height: 70px;
    --container-max-width: 1200px;
}

/* Dark Theme (Default) */
.dark-theme {
    --bg-main: #0b0f19;
    --bg-card: #151d30;
    --bg-header: rgba(11, 15, 25, 0.8);
    --bg-hover: #1e2942;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-focus: #3b82f6;

    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --accent-blue: #3b82f6;
    --accent-blue-glow: rgba(59, 130, 246, 0.15);
    --accent-emerald: #10b981;
    --accent-emerald-glow: rgba(16, 185, 129, 0.15);
    --accent-purple: #8b5cf6;
    --accent-purple-glow: rgba(139, 92, 246, 0.15);
    --accent-red: #ef4444;
    --accent-red-glow: rgba(239, 68, 68, 0.15);
    
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.4);
    
    --hero-gradient: radial-gradient(circle at 50% 20%, #1e2942 0%, #0b0f19 70%);
    --card-glow: linear-gradient(135deg, rgba(59, 130, 246, 0.1) 0%, rgba(139, 92, 246, 0.05) 100%);
    
    --code-bg: #090d16;
    --code-text: #60a5fa;
}

/* Light Theme */
.light-theme {
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --bg-header: rgba(248, 250, 252, 0.85);
    --bg-hover: #f1f5f9;
    --border-color: rgba(0, 0, 0, 0.08);
    --border-focus: #2563eb;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    --accent-blue: #2563eb;
    --accent-blue-glow: rgba(37, 99, 235, 0.08);
    --accent-emerald: #059669;
    --accent-emerald-glow: rgba(5, 150, 105, 0.08);
    --accent-purple: #7c3aed;
    --accent-purple-glow: rgba(124, 58, 237, 0.08);
    --accent-red: #dc2626;
    --accent-red-glow: rgba(220, 38, 38, 0.08);
    
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.08);
    
    --hero-gradient: radial-gradient(circle at 50% 20%, #e2e8f0 0%, #f8fafc 70%);
    --card-glow: linear-gradient(135deg, rgba(37, 99, 235, 0.04) 0%, rgba(124, 58, 237, 0.03) 100%);
    
    --code-bg: #f1f5f9;
    --code-text: #2563eb;
}

/* ==========================================================================
   Base Styles & Reset
   ========================================================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    font-family: var(--font-body);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    transition: background-color var(--transition-medium), color var(--transition-medium);
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: var(--container-max-width);
    margin: 0 auto;
}

code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background-color: var(--code-bg);
    color: var(--code-text);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

/* ==========================================================================
   Header Component
   ========================================================================== */
.main-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background-color: var(--bg-header);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: background-color var(--transition-medium), border-color var(--transition-medium);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 5%;
}

.logo {
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 1.5rem;
    letter-spacing: -0.03em;
    color: var(--text-primary);
}

.logo-accent {
    color: var(--accent-blue);
}

.header-nav {
    display: flex;
    gap: 2rem;
}

.nav-link-top {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color var(--transition-fast);
}

.nav-link-top:hover {
    color: var(--accent-blue);
}

/* Theme Switcher Button */
.theme-toggle-btn {
    background: none;
    border: 1px solid var(--border-color);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.theme-toggle-btn:hover {
    background-color: var(--bg-hover);
    border-color: var(--text-secondary);
}

.dark-theme .sun-icon { display: block; }
.dark-theme .moon-icon { display: none; }
.light-theme .sun-icon { display: none; }
.light-theme .moon-icon { display: block; }

.sun-icon, .moon-icon {
    stroke: currentColor;
    transition: transform var(--transition-medium);
}

.theme-toggle-btn:hover svg {
    transform: rotate(20deg);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
    position: relative;
    padding: calc(var(--header-height) + 4rem) 0 4rem;
    background: var(--hero-gradient);
    border-bottom: 1px solid var(--border-color);
    text-align: center;
    overflow: hidden;
}

.hero-glow {
    position: absolute;
    top: -50px;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 300px;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.15) 0%, rgba(139, 92, 246, 0.05) 50%, rgba(0,0,0,0) 100%);
    filter: blur(40px);
    z-index: 1;
    pointer-events: none;
}

.hero-container {
    position: relative;
    z-index: 2;
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1rem;
}

.meta-tag {
    display: inline-block;
    padding: 0.35rem 0.85rem;
    border-radius: 20px;
    background-color: var(--accent-blue-glow);
    color: var(--accent-blue);
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1.5rem;
    border: 1px solid rgba(59, 130, 246, 0.2);
    animation: fadeInDown var(--transition-slow);
}

.hero-title {
    font-family: var(--font-heading);
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.25;
    letter-spacing: -0.04em;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    animation: fadeInUp var(--transition-slow);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto 2rem;
    line-height: 1.6;
    animation: fadeInUp var(--transition-slow) 0.1s;
}

.hero-meta {
    display: flex;
    justify-content: center;
    gap: 2rem;
    font-size: 0.9rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
    max-width: 600px;
    margin: 0 auto;
    animation: fadeInUp var(--transition-slow) 0.2s;
}

.meta-item {
    display: flex;
    gap: 0.5rem;
}

.meta-value {
    color: var(--text-secondary);
    font-weight: 500;
}

/* ==========================================================================
   Layout & Sidebar Components
   ========================================================================== */
.main-layout {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 3rem;
    padding: 3.5rem 0;
}

.sidebar {
    position: relative;
}

.sidebar-sticky {
    position: sticky;
    top: calc(var(--header-height) + 2rem);
}

.sidebar-title {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.toc {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.toc-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-left: 2px solid var(--border-color);
    transition: all var(--transition-fast);
}

.toc-link:hover {
    color: var(--accent-blue);
    border-left-color: var(--accent-blue);
    background-color: var(--bg-hover);
    border-top-right-radius: 4px;
    border-bottom-right-radius: 4px;
}

.toc-link.active {
    color: var(--accent-blue);
    border-left-color: var(--accent-blue);
    background-color: var(--accent-blue-glow);
    font-weight: 600;
    border-top-right-radius: 4px;
    border-bottom-right-radius: 4px;
}

.toc-link.sub-link {
    padding-left: 2rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.toc-link.sub-link.active {
    color: var(--accent-blue);
}

/* ==========================================================================
   Article Content Structure
   ========================================================================== */
.content-area {
    max-width: 800px;
}

.article-section {
    margin-bottom: 5rem;
}

.article-section h2 {
    font-family: var(--font-heading);
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

.article-section p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

.quote-card {
    background: var(--card-glow);
    border-left: 4px solid var(--accent-blue);
    padding: 1.5rem 2rem;
    margin: 2rem 0;
    border-radius: 0 8px 8px 0;
    box-shadow: var(--shadow-sm);
}

.quote-card p {
    margin: 0;
    font-size: 1.15rem;
    font-style: italic;
    color: var(--text-primary);
}

/* ==========================================================================
   Tech Stack Grid
   ========================================================================== */
.tech-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin: 2.5rem 0;
}

.tech-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-medium), border-color var(--transition-fast), box-shadow var(--transition-medium);
}

.tech-card:hover {
    transform: translateY(-4px);
    border-color: rgba(59, 130, 246, 0.4);
    box-shadow: var(--shadow-md);
}

.tech-card.fill-width {
    grid-column: 1 / -1;
}

.tech-card-icon {
    width: 48px;
    height: 48px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.25rem;
    color: white;
}

.fontend-icon { background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%); }
.backend-icon { background: linear-gradient(135deg, #8b5cf6 0%, #7c3aed 100%); }
.database-icon { background: linear-gradient(135deg, #10b981 0%, #059669 100%); }

.tech-card h3 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.tech-card strong {
    color: var(--accent-blue);
}

.tech-card ul {
    list-style: none;
    margin-top: 1rem;
}

.tech-card li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.tech-card li::before {
    content: "•";
    position: absolute;
    left: 0.5rem;
    color: var(--accent-blue);
    font-weight: bold;
}

/* ==========================================================================
   Interactive Containers & Animations
   ========================================================================== */
.interactive-container {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem;
    margin: 3rem 0;
    box-shadow: var(--shadow-md);
}

.container-header {
    margin-bottom: 2rem;
}

.container-header h4 {
    font-family: var(--font-heading);
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.container-subheader {
    font-size: 0.95rem;
    color: var(--text-muted);
}

/* RAG Flow Diagram */
.rag-flow {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.rag-step {
    flex: 1;
    text-align: center;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    padding: 1.25rem 0.75rem;
    border-radius: 12px;
    cursor: pointer;
    position: relative;
    transition: all var(--transition-medium);
}

.rag-step:hover {
    border-color: var(--accent-blue);
    transform: translateY(-2px);
}

.rag-step.active {
    border-color: var(--accent-blue);
    background-color: var(--accent-blue-glow);
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.15);
}

.step-num {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background-color: var(--border-color);
    color: var(--text-secondary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
    margin-bottom: 0.75rem;
    transition: all var(--transition-fast);
}

.rag-step.active .step-num {
    background-color: var(--accent-blue);
    color: white;
}

.step-title {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 0.25rem;
}

.step-desc {
    display: none; /* Accessible details are stored here or mapped in script.js */
}

.flow-arrow {
    font-size: 1.5rem;
    color: var(--border-color);
    transition: color var(--transition-fast);
}

.rag-step.active + .flow-arrow {
    color: var(--accent-blue);
}

.rag-details-box {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.25rem 1.5rem;
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-secondary);
    border-left: 3px solid var(--accent-blue);
    min-height: 80px;
    animation: fadeIn var(--transition-medium);
}

/* ==========================================================================
   Exam Practice Widget
   ========================================================================== */
.exam-widget {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
}

.exam-question {
    margin-bottom: 1.5rem;
}

.question-badge {
    display: inline-block;
    padding: 0.25rem 0.6rem;
    background-color: var(--accent-purple-glow);
    color: var(--accent-purple);
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: 4px;
    margin-bottom: 0.75rem;
}

.question-text {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.exam-answers {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.answer-option {
    display: flex;
    align-items: center;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.answer-option:hover {
    border-color: var(--accent-purple);
    background-color: var(--bg-hover);
}

.answer-option input[type="radio"] {
    display: none;
}

.option-custom {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    margin-right: 0.75rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    position: relative;
    transition: all var(--transition-fast);
}

.answer-option input[type="radio"]:checked + .option-custom {
    border-color: var(--accent-purple);
}

.answer-option input[type="radio"]:checked + .option-custom::after {
    content: "";
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: var(--accent-purple);
    position: absolute;
}

.option-text {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.exam-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.primary-btn {
    align-self: flex-start;
    background: linear-gradient(135deg, var(--accent-blue) 0%, #1e40af 100%);
    color: white;
    border: none;
    padding: 0.8rem 1.75rem;
    font-family: var(--font-heading);
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: 0 4px 12px var(--accent-blue-glow);
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(59, 130, 246, 0.3);
}

.exam-feedback {
    background-color: var(--bg-card);
    border-radius: 8px;
    padding: 1.25rem 1.5rem;
    font-size: 0.95rem;
    line-height: 1.6;
    border-left: 4px solid var(--border-color);
    animation: slideDown var(--transition-medium);
}

.exam-feedback.success {
    border-left-color: var(--accent-emerald);
    background-color: var(--accent-emerald-glow);
    color: var(--text-primary);
}

.exam-feedback.error {
    border-left-color: var(--accent-red);
    background-color: var(--accent-red-glow);
    color: var(--text-primary);
}

.exam-feedback.hidden {
    display: none;
}

/* ==========================================================================
   AI Chat Widget Component
   ========================================================================== */
.chat-widget {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    height: 480px;
    overflow: hidden;
}

.chat-header {
    background-color: var(--bg-card);
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.chat-avatar {
    position: relative;
}

.avatar-inner {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
    color: white;
    font-family: var(--font-heading);
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
}

.avatar-status {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: var(--accent-emerald);
    border: 2px solid var(--bg-card);
}

.chat-name {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 0.95rem;
}

.chat-desc {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.chat-body {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    background-color: var(--bg-main);
}

.message {
    display: flex;
    max-width: 80%;
}

.message.bot {
    align-self: flex-start;
}

.message.user {
    align-self: flex-end;
}

.message-bubble {
    padding: 0.9rem 1.2rem;
    border-radius: 12px;
    font-size: 0.95rem;
    line-height: 1.5;
    position: relative;
    word-break: break-word;
    box-shadow: var(--shadow-sm);
}

.message.bot .message-bubble {
    background-color: var(--bg-card);
    color: var(--text-primary);
    border-bottom-left-radius: 2px;
    border: 1px solid var(--border-color);
}

.message.user .message-bubble {
    background: linear-gradient(135deg, var(--accent-blue) 0%, #1e40af 100%);
    color: white;
    border-bottom-right-radius: 2px;
}

/* Typing Indicator & SSE Effect */
.typing-cursor {
    display: inline-block;
    width: 6px;
    height: 15px;
    background-color: var(--accent-blue);
    margin-left: 2px;
    animation: blink 0.8s infinite;
    vertical-align: middle;
}

.chat-suggestions {
    display: flex;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background-color: var(--bg-card);
    border-top: 1px solid var(--border-color);
    overflow-x: auto;
    white-space: nowrap;
}

.chat-suggestions::-webkit-scrollbar {
    display: none;
}

.suggest-btn {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.4rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    cursor: pointer;
    white-space: nowrap;
    transition: all var(--transition-fast);
}

.suggest-btn:hover {
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    background-color: var(--accent-blue-glow);
}

.chat-input-area {
    display: flex;
    background-color: var(--bg-card);
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
    gap: 0.75rem;
}

.chat-input-area input {
    flex: 1;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.75rem 1rem;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.95rem;
    outline: none;
    transition: border-color var(--transition-fast);
}

.chat-input-area input:focus {
    border-color: var(--border-focus);
}

.send-btn {
    background-color: var(--accent-blue);
    border: none;
    color: white;
    width: 44px;
    height: 44px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.send-btn:hover {
    background-color: #2563eb;
    transform: scale(1.05);
}

/* ==========================================================================
   Alerts, Lists, and General Styling
   ========================================================================== */
.alert-box {
    border-radius: 8px;
    padding: 1.25rem 1.5rem;
    margin: 2rem 0;
    box-shadow: var(--shadow-sm);
}

.alert-box.note {
    background-color: var(--accent-blue-glow);
    border-left: 4px solid var(--accent-blue);
}

.alert-box h5 {
    font-family: var(--font-heading);
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.alert-box p {
    margin: 0;
    font-size: 0.95rem;
    color: var(--text-primary);
}

/* Info Cards Block */
.info-cards {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    margin: 2rem 0;
}

.info-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.75rem;
    position: relative;
    box-shadow: var(--shadow-sm);
}

.info-card-badge {
    position: absolute;
    top: 1.75rem;
    right: 1.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

.info-card h4 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.info-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin: 0;
}

/* ==========================================================================
   Timeline / Roadmap Component
   ========================================================================== */
.timeline {
    position: relative;
    padding-left: 2rem;
    margin: 2.5rem 0;
}

.timeline::before {
    content: "";
    position: absolute;
    left: 7px;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: var(--border-color);
}

.timeline-step {
    position: relative;
    margin-bottom: 2rem;
}

.timeline-dot {
    position: absolute;
    left: -2rem;
    top: 6px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background-color: var(--bg-main);
    border: 3px solid var(--accent-blue);
    z-index: 2;
}

.timeline-content h4 {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.15rem;
    margin-bottom: 0.25rem;
}

.timeline-content p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin: 0;
}

/* ==========================================================================
   CTA Banner Component
   ========================================================================== */
.cta-banner {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    border: 1px solid rgba(59, 130, 246, 0.25);
    border-radius: 16px;
    padding: 3rem;
    text-align: center;
    margin-top: 4rem;
    position: relative;
    overflow: hidden;
}

.cta-banner::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
}

.cta-banner h3 {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 0.75rem;
}

.cta-banner p {
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 2rem;
}

.cta-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.secondary-btn {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.8rem 1.75rem;
    font-family: var(--font-heading);
    font-weight: 600;
    border-radius: 8px;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.cta-actions .primary-btn {
    text-decoration: none;
}

/* ==========================================================================
   Footer Component
   ========================================================================== */
.main-footer {
    background-color: var(--bg-card);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0;
    margin-top: 5rem;
    transition: background-color var(--transition-medium), border-color var(--transition-medium);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-brand {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.15rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--accent-blue);
}

/* ==========================================================================
   Keyframe Animations
   ========================================================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

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

/* ==========================================================================
   Responsive Adaptations
   ========================================================================== */
@media (max-width: 992px) {
    .main-layout {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .sidebar {
        display: none; /* Hide sticky sidebar on medium and small screens to focus on article */
    }

    .hero-title {
        font-size: 2.25rem;
    }
}

@media (max-width: 768px) {
    .header-nav {
        display: none; /* Simple navbar for mobile */
    }
    
    .tech-grid {
        grid-template-columns: 1fr;
    }

    .rag-flow {
        flex-direction: column;
        gap: 1rem;
    }

    .flow-arrow {
        transform: rotate(90deg);
        margin: 0.25rem 0;
    }

    .exam-answers {
        grid-template-columns: 1fr;
    }

    .cta-actions {
        flex-direction: column;
        gap: 0.75rem;
    }

    .cta-actions .primary-btn, 
    .cta-actions .secondary-btn {
        width: 100%;
        display: inline-block;
        box-sizing: border-box;
    }
}

/* ==========================================================================
   Team / About Us Section Component
   ========================================================================== */
.team-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: 2.5rem 0;
}

.team-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-medium), border-color var(--transition-fast), box-shadow var(--transition-medium);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.team-card:hover {
    transform: translateY(-4px);
    border-color: rgba(59, 130, 246, 0.4);
    box-shadow: var(--shadow-md);
}

.team-avatar-wrapper {
    margin-bottom: 1.5rem;
    position: relative;
}

.team-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
    color: white;
    font-family: var(--font-heading);
    font-size: 1.75rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.25);
    border: 3px solid var(--bg-card);
}

.team-card h3 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.team-role {
    font-size: 0.9rem;
    color: var(--accent-blue);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1.5rem;
}

.team-contacts {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    width: 100%;
    margin-top: auto;
}

.team-contact-link {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.6rem 1rem;
    border-radius: 8px;
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.team-contact-link svg {
    color: var(--text-muted);
    transition: color var(--transition-fast);
}

.team-contact-link:hover {
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    background-color: var(--accent-blue-glow);
}

.team-contact-link.github:hover {
    border-color: var(--text-primary);
    color: var(--text-primary);
    background-color: var(--bg-hover);
}

.team-contact-link.telegram:hover {
    border-color: #38bdf8;
    color: #38bdf8;
    background-color: rgba(56, 189, 248, 0.08);
}

.team-contact-link:hover svg {
    color: inherit;
}

/* Mobile responsive for team grid */
@media (max-width: 768px) {
    .team-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}