/* 
   CodeMaster - Professional Educational Platform Core Stylesheet
   Design System, Components, Layouts, Custom Syntax Highlighting, and Accessibility Elements
*/

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

/* --- Core Theme Variables (Light Theme Defaults) --- */
:root {
    --font-primary: 'Inter', sans-serif;
    --font-heading: 'Outfit', sans-serif;
    
    /* Colors */
    --primary: #4f46e5;
    --primary-light: #818cf8;
    --primary-dark: #3730a3;
    --primary-gradient: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
    --accent: #06b6d4;
    --accent-light: #22d3ee;
    --accent-gradient: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
    
    /* Backgrounds */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --bg-footer: #0f172a;
    
    /* Text Colors */
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #64748b;
    --text-light: #f8fafc;
    
    /* Borders & Accents */
    --border-color: #e2e8f0;
    --border-focus: #818cf8;
    
    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.5);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.05);
    
    /* Shadows */
    --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);
    
    /* Radii */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-full: 9999px;
    
    /* Animations */
    --transition-all: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Layout */
    --header-height: 70px;
    --max-width: 1280px;
}

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

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

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

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

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

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

input, textarea, button, select {
    font-family: inherit;
    font-size: inherit;
    color: inherit;
    outline: none;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.25;
    margin-bottom: 0.5em;
    color: var(--text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

/* --- Reading Progress Bar --- */
#reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: var(--primary-gradient);
    width: 0%;
    z-index: 1001;
    transition: width 0.1s ease-out;
}

/* --- Sticky Navigation Bar --- */
header.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background-color: var(--glass-bg);
    backdrop-filter: blur(12px) saturate(180%);
    -webkit-backdrop-filter: blur(12px) saturate(180%);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    z-index: 1000;
    transition: var(--transition-all);
}

header.site-header.scrolled {
    background-color: var(--bg-secondary);
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: var(--max-width);
    height: 100%;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.brand-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
}

.brand-logo span {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-logo svg {
    width: 32px;
    height: 32px;
    fill: var(--primary);
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    padding: 0.5rem 0;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-gradient);
    transition: var(--transition-all);
}

.nav-link:hover::after, .nav-link.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Light/Dark Toggle Button */
.theme-toggle-btn {
    background: none;
    border: 1px solid var(--border-color);
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: var(--transition-all);
    color: var(--text-secondary);
}

.theme-toggle-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
    background-color: var(--bg-tertiary);
    transform: translateY(-2px);
}

.theme-toggle-btn svg {
    width: 20px;
    height: 20px;
}

.theme-toggle-btn .sun-icon {
    display: none;
}

.theme-toggle-btn .moon-icon {
    display: block;
}

/* Custom CTA Button */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-all);
    border: none;
}

.btn-primary {
    background: var(--primary-gradient);
    color: var(--text-light);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.btn-primary:hover {
    box-shadow: 0 6px 16px rgba(79, 70, 229, 0.4);
    transform: translateY(-2px);
    color: var(--text-light);
}

.btn-secondary {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--text-secondary);
    transform: translateY(-2px);
}

.btn-icon {
    padding: 0.5rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-all);
}

.btn-icon:hover {
    color: var(--primary);
    border-color: var(--primary);
    background-color: var(--bg-tertiary);
}

/* Mobile Nav Toggle */
.mobile-nav-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.75rem;
    cursor: pointer;
}

/* --- Container & Layout --- */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
}

main.main-content {
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height) - 350px); /* Adjust based on footer height */
}

/* --- Hero Section --- */
.hero-section {
    position: relative;
    padding: 6rem 0;
    background: radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.05) 0%, rgba(168, 85, 247, 0.02) 90.2%);
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    width: 300px;
    height: 300px;
    border-radius: var(--radius-full);
    background: var(--primary-light);
    filter: blur(150px);
    top: -50px;
    right: -50px;
    opacity: 0.15;
    z-index: 0;
}

.hero-section::after {
    content: '';
    position: absolute;
    width: 250px;
    height: 250px;
    border-radius: var(--radius-full);
    background: var(--accent);
    filter: blur(120px);
    bottom: -50px;
    left: -50px;
    opacity: 0.1;
    z-index: 0;
}

.hero-container {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 4rem;
    align-items: center;
}

.hero-content {
    max-width: 650px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background-color: rgba(79, 70, 229, 0.1);
    color: var(--primary);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.hero-badge span {
    width: 8px;
    height: 8px;
    border-radius: var(--radius-full);
    background-color: var(--accent);
    box-shadow: 0 0 8px var(--accent);
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0% { transform: scale(0.95); opacity: 0.5; }
    50% { transform: scale(1.15); opacity: 1; }
    100% { transform: scale(0.95); opacity: 0.5; }
}

.hero-title {
    font-size: 3.5rem;
    line-height: 1.15;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--text-primary) 30%, var(--primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
}

.hero-stats {
    display: flex;
    gap: 3rem;
    border-top: 1px solid var(--border-color);
    padding-top: 2rem;
}

.stat-item h4 {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 0.25rem;
}

.stat-item p {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
}

.hero-illustration {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-illustration svg {
    max-width: 100%;
    filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.15));
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0% { transform: translateY(0px); }
    50% { transform: translateY(-15px); }
    100% { transform: translateY(0px); }
}

/* --- Section Formatting --- */
.section {
    padding: 5rem 0;
}

.section-bg {
    background-color: var(--bg-secondary);
}

.section-header {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 3.5rem auto;
}

.section-tag {
    color: var(--primary);
    font-weight: 700;
    text-transform: uppercase;
    font-size: 0.875rem;
    letter-spacing: 0.1em;
    margin-bottom: 0.75rem;
    display: inline-block;
}

.section-title {
    font-size: 2.25rem;
    margin-bottom: 1rem;
}

.section-desc {
    color: var(--text-secondary);
}

/* --- Grid layouts --- */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
}

/* --- Glassmorphic Card Components --- */
.card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 2rem;
    transition: var(--transition-all);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--border-focus);
}

.card-icon-wrapper {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    background: var(--primary-gradient);
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 1.5rem;
    color: var(--text-light);
}

.card-icon-wrapper svg {
    width: 24px;
    height: 24px;
    fill: currentColor;
}

.card-title {
    margin-bottom: 0.75rem;
}

.card-desc {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.card-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    color: var(--primary);
    font-size: 0.9375rem;
}

.card-link svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
    transition: var(--transition-all);
}

.card:hover .card-link svg {
    transform: translateX(4px);
}

/* --- Category Badge Buttons --- */
.category-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
}

.badge-html { background-color: rgba(240, 101, 41, 0.1); color: #f06529; }
.badge-css { background-color: rgba(41, 169, 224, 0.1); color: #29a9e0; }
.badge-javascript { background-color: rgba(247, 223, 30, 0.15); color: #b59300; }
.badge-projects { background-color: rgba(16, 185, 129, 0.1); color: #10b981; }
.badge-interview { background-color: rgba(168, 85, 247, 0.1); color: #a855f7; }
.badge-blog { background-color: rgba(236, 72, 153, 0.1); color: #ec4899; }

/* --- Breadcrumbs --- */
.breadcrumb-container {
    padding: 1.5rem 0 0.5rem 0;
}

.breadcrumbs {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.breadcrumb-item a {
    color: var(--text-secondary);
}

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

.breadcrumb-item.active {
    color: var(--text-muted);
}

.breadcrumb-separator {
    display: flex;
    align-items: center;
}

.breadcrumb-separator svg {
    width: 12px;
    height: 12px;
    fill: currentColor;
}

/* --- Article Detail Layout & Sidebars --- */
.article-detail-layout {
    display: grid;
    grid-template-columns: 260px 1fr 260px;
    gap: 2rem;
    padding: 2rem 0 5rem 0;
}

.sidebar-left {
    position: sticky;
    top: calc(var(--header-height) + 2rem);
    height: calc(100vh - var(--header-height) - 4rem);
    overflow-y: auto;
    padding-right: 1rem;
}

.sidebar-right {
    position: sticky;
    top: calc(var(--header-height) + 2rem);
    height: calc(100vh - var(--header-height) - 4rem);
    overflow-y: auto;
    padding-left: 1rem;
}

.sidebar-left::-webkit-scrollbar, .sidebar-right::-webkit-scrollbar {
    width: 4px;
}

.sidebar-left::-webkit-scrollbar-thumb, .sidebar-right::-webkit-scrollbar-thumb {
    background-color: var(--border-color);
    border-radius: var(--radius-full);
}

.sidebar-title {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 1rem;
    font-weight: 700;
}

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

.sidebar-link {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    display: block;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    transition: var(--transition-all);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sidebar-link:hover, .sidebar-link.active {
    background-color: var(--bg-tertiary);
    color: var(--primary);
    padding-left: 0.75rem;
}

/* Table of Contents */
.toc-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.toc-link {
    font-size: 0.875rem;
    color: var(--text-secondary);
    padding: 0.25rem 0;
    display: block;
    border-left: 2px solid var(--border-color);
    padding-left: 0.75rem;
}

.toc-link:hover, .toc-link.active {
    color: var(--primary);
    border-color: var(--primary);
}

/* --- Main Article Rendering Panel --- */
.article-container {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 3rem;
    box-shadow: var(--shadow-sm);
}

.article-header {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 2rem;
    margin-bottom: 2.5rem;
}

.article-meta {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.article-meta-item {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.article-meta-item svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
}

.article-title-main {
    font-size: 2.75rem;
    margin-bottom: 1rem;
}

.article-body h2 {
    font-size: 1.75rem;
    margin: 2.5rem 0 1rem 0;
    position: relative;
    padding-bottom: 0.5rem;
}

.article-body h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 3px;
    background: var(--primary-gradient);
    border-radius: var(--radius-full);
}

.article-body h3 {
    font-size: 1.35rem;
    margin: 2rem 0 1rem 0;
}

.article-body p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
}

/* Interactive Accordions for FAQ / Interview Questions */
.accordion-item {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: 1rem;
    background-color: var(--bg-secondary);
    overflow: hidden;
    transition: var(--transition-all);
}

.accordion-header {
    padding: 1.25rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-weight: 600;
    background-color: var(--bg-tertiary);
    transition: var(--transition-all);
}

.accordion-header:hover {
    background-color: var(--border-color);
    color: var(--primary);
}

.accordion-icon {
    width: 20px;
    height: 20px;
    fill: currentColor;
    transition: transform 0.3s ease;
}

.accordion-content {
    padding: 0;
    height: 0;
    overflow: hidden;
    transition: height 0.3s ease, padding 0.3s ease;
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
}

.accordion-item.active {
    border-color: var(--primary);
}

.accordion-item.active .accordion-header {
    background-color: rgba(79, 70, 229, 0.05);
    color: var(--primary);
}

.accordion-item.active .accordion-icon {
    transform: rotate(180deg);
}

.accordion-item.active .accordion-content {
    padding: 1.5rem;
    height: auto;
    border-top: 1px solid var(--border-color);
}

/* Note, Tips, and Best Practices blocks */
.content-box {
    padding: 1.5rem;
    border-radius: var(--radius-md);
    margin: 2rem 0;
    border-left: 4px solid;
    background-color: var(--bg-tertiary);
}

.box-note {
    border-left-color: var(--primary);
    background-color: rgba(79, 70, 229, 0.03);
}

.box-note-title {
    color: var(--primary);
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.box-tip {
    border-left-color: var(--accent);
    background-color: rgba(6, 182, 212, 0.03);
}

.box-tip-title {
    color: var(--accent);
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.best-practices-list {
    margin: 1.5rem 0;
}

.best-practice-item {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
    align-items: flex-start;
}

.best-practice-item svg {
    width: 20px;
    height: 20px;
    fill: #10b981;
    flex-shrink: 0;
    margin-top: 0.2rem;
}

/* --- Code & Syntax Highlighting Blocks --- */
.code-block-wrapper {
    position: relative;
    margin: 2rem 0;
    border-radius: var(--radius-md);
    overflow: hidden;
    background-color: #1e1e2e;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.code-block-header {
    background-color: #151521;
    padding: 0.75rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.code-language {
    color: #cdd6f4;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.copy-code-btn {
    background: none;
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: #a6adc8;
    padding: 0.4rem 0.8rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    cursor: pointer;
    transition: var(--transition-all);
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.copy-code-btn:hover {
    color: #f5c2e7;
    background-color: rgba(255, 255, 255, 0.05);
    border-color: #f5c2e7;
}

.copy-code-btn svg {
    width: 14px;
    height: 14px;
    fill: currentColor;
}

pre {
    padding: 1.5rem;
    overflow-x: auto;
    margin: 0;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.95rem;
    line-height: 1.5;
}

code {
    color: #cdd6f4;
}

/* Custom CSS Highlighting Classes */
.code-keyword { color: #cba6f7; font-weight: bold; }
.code-string { color: #a6e3a1; }
.code-comment { color: #585b70; font-style: italic; }
.code-function { color: #89b4fa; }
.code-number { color: #fab387; }
.code-operator { color: #89dceb; }
.code-type { color: #f9e2af; }
.code-tag { color: #f38ba8; }
.code-attr { color: #fab387; }

/* Output Code Render Preview */
.output-preview {
    margin: -1.5rem 2rem 2.5rem 2rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    border-top: none;
    border-bottom-left-radius: var(--radius-md);
    border-bottom-right-radius: var(--radius-md);
    background-color: var(--bg-tertiary);
}

.output-title {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    letter-spacing: 0.05em;
}

.output-content {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 1rem;
}

/* Next / Prev Navigation inside articles */
.article-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    border-top: 1px solid var(--border-color);
    padding-top: 2rem;
    margin-top: 3rem;
}

.article-nav-btn {
    display: flex;
    flex-direction: column;
    padding: 1.25rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: var(--transition-all);
}

.article-nav-btn:hover {
    border-color: var(--primary);
    background-color: rgba(79, 70, 229, 0.02);
}

.article-nav-btn.prev {
    align-items: flex-start;
}

.article-nav-btn.next {
    align-items: flex-end;
    text-align: right;
}

.article-nav-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.article-nav-title {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 1.05rem;
}

.article-nav-btn:hover .article-nav-title {
    color: var(--primary);
}

/* --- Search Engine styling --- */
.search-header-container {
    padding: 4rem 0;
    background: linear-gradient(180deg, var(--bg-tertiary) 0%, var(--bg-primary) 100%);
    text-align: center;
}

.search-input-wrapper {
    position: relative;
    max-width: 600px;
    margin: 2rem auto 0 auto;
}

.search-input-wrapper input {
    width: 100%;
    padding: 1.25rem 1.5rem 1.25rem 3.5rem;
    border-radius: var(--radius-full);
    border: 2px solid var(--border-color);
    background-color: var(--bg-secondary);
    font-size: 1.125rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition-all);
}

.search-input-wrapper input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.15);
}

.search-input-wrapper svg {
    position: absolute;
    left: 1.5rem;
    top: 50%;
    transform: translateY(-50%);
    width: 24px;
    height: 24px;
    fill: var(--text-muted);
    pointer-events: none;
}

.search-results-meta {
    max-width: var(--max-width);
    margin: 2rem auto;
    padding: 0 2rem;
    color: var(--text-muted);
    font-weight: 500;
}

.search-highlight {
    background-color: rgba(247, 223, 30, 0.3);
    padding: 0 2px;
    border-radius: 2px;
    font-weight: 600;
}

/* --- Projects Interactive Layouts --- */
.project-card {
    display: flex;
    flex-direction: column;
}

.project-card-header {
    position: relative;
    height: 180px;
    background: var(--primary-gradient);
    border-top-left-radius: var(--radius-md);
    border-top-right-radius: var(--radius-md);
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.project-demo-box {
    margin-top: 1.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    background-color: var(--bg-tertiary);
}

/* Simulator/Interactive widget styles */
.calculator-widget {
    background-color: #1e1e2e;
    padding: 1rem;
    border-radius: var(--radius-md);
    max-width: 280px;
    margin: 0 auto;
}

.calc-display {
    background-color: #11111b;
    color: #a6e3a1;
    font-family: 'Courier New', Courier, monospace;
    font-size: 1.5rem;
    padding: 0.75rem;
    text-align: right;
    border-radius: var(--radius-sm);
    margin-bottom: 1rem;
    overflow-x: auto;
    min-height: 48px;
}

.calc-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
}

.calc-btn {
    background-color: #313244;
    color: #cdd6f4;
    border: none;
    padding: 0.75rem 0;
    font-size: 1.15rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition-all);
}

.calc-btn:hover {
    background-color: #45475a;
}

.calc-btn.op {
    background-color: var(--primary);
    color: white;
}

.calc-btn.op:hover {
    background-color: var(--primary-dark);
}

.calc-btn.eq {
    background-color: #10b981;
    color: white;
    grid-column: span 2;
}

.calc-btn.eq:hover {
    background-color: #059669;
}

/* Digital Clock Widget */
.clock-widget {
    background-color: #0f172a;
    border: 2px solid var(--primary);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-align: center;
    color: #06b6d4;
    font-family: monospace;
    font-size: 2.5rem;
    font-weight: bold;
    box-shadow: 0 0 15px rgba(6, 182, 212, 0.2);
    max-width: 300px;
    margin: 0 auto;
}

/* Stopwatch Widget */
.stopwatch-widget {
    background-color: #1e293b;
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-align: center;
    max-width: 300px;
    margin: 0 auto;
}

.stopwatch-display {
    font-size: 2.25rem;
    font-family: monospace;
    font-weight: bold;
    margin-bottom: 1rem;
    color: var(--text-light);
}

.stopwatch-controls {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
}

/* Todo App Widget */
.todo-widget {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    max-width: 350px;
    margin: 0 auto;
    box-shadow: var(--shadow-md);
}

.todo-input-group {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.todo-input-group input {
    flex-grow: 1;
    border: 1px solid var(--border-color);
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    background-color: var(--bg-tertiary);
}

.todo-list {
    max-height: 200px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.todo-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: var(--bg-tertiary);
    padding: 0.5rem;
    border-radius: var(--radius-sm);
}

.todo-item.completed span {
    text-decoration: line-through;
    color: var(--text-muted);
}

.todo-item-btn {
    background: none;
    border: none;
    color: #ef4444;
    cursor: pointer;
}

/* Password Generator Widget */
.password-widget {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    max-width: 320px;
    margin: 0 auto;
    box-shadow: var(--shadow-md);
}

.password-display-box {
    display: flex;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.5rem 0.75rem;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.password-text {
    font-family: monospace;
    font-weight: 600;
    overflow-x: auto;
}

.password-settings {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.password-setting-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Quiz App Widget */
.quiz-widget {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    max-width: 400px;
    margin: 0 auto;
    box-shadow: var(--shadow-md);
}

.quiz-question {
    font-weight: 600;
    margin-bottom: 1rem;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.quiz-option-btn {
    text-align: left;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    padding: 0.75rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition-all);
}

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

.quiz-option-btn.correct {
    background-color: #10b981;
    color: white;
}

.quiz-option-btn.incorrect {
    background-color: #ef4444;
    color: white;
}

/* --- Contact validation styling --- */
.contact-form {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

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

.form-group.full-width {
    grid-column: span 2;
}

.form-group label {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.form-group input, .form-group textarea, .form-group select {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.75rem;
    background-color: var(--bg-secondary);
    transition: var(--transition-all);
}

.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-error-msg {
    color: #ef4444;
    font-size: 0.75rem;
    font-weight: 500;
    display: none;
}

.form-success-box {
    grid-column: span 2;
    padding: 1.5rem;
    background-color: rgba(16, 185, 129, 0.05);
    border: 1px solid #10b981;
    color: #065f46;
    border-radius: var(--radius-md);
    text-align: center;
    display: none;
    font-weight: 500;
}

/* --- Newsletter layout --- */
.newsletter-section {
    background: var(--primary-gradient);
    color: var(--text-light);
    padding: 5rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.newsletter-section h2, .newsletter-section p {
    color: var(--text-light);
}

.newsletter-form {
    display: flex;
    max-width: 500px;
    margin: 2.5rem auto 0 auto;
    gap: 0.5rem;
}

.newsletter-form input {
    flex-grow: 1;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    border: 1px solid rgba(255, 255, 255, 0.2);
    background-color: rgba(255, 255, 255, 0.15);
    color: var(--text-light);
}

.newsletter-form input::placeholder {
    color: rgba(255, 255, 255, 0.6);
}

.newsletter-form input:focus {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
}

/* --- Testimonials --- */
.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.testimonial-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
}

.testimonial-rating {
    color: #fbbf24;
    display: flex;
    gap: 0.25rem;
    margin-bottom: 1rem;
}

.testimonial-user {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-top: 1.5rem;
}

.testimonial-user-avatar {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    background-color: var(--primary-light);
    color: white;
    font-weight: 700;
    display: flex;
    justify-content: center;
    align-items: center;
}

.testimonial-user-info h5 {
    margin: 0;
}

.testimonial-user-info p {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* --- Pagination Elements --- */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
    margin: 3rem 0;
}

.pagination-btn {
    width: 40px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    background-color: var(--bg-secondary);
    transition: var(--transition-all);
}

.pagination-btn:hover, .pagination-btn.active {
    background-color: var(--primary);
    color: white;
    border-color: var(--primary);
}

.pagination-btn.disabled {
    opacity: 0.5;
    pointer-events: none;
}

/* --- Google AdSense Responsive Layout Slots --- */
.adsense-placeholder {
    margin: 2rem 0;
    padding: 1rem;
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--bg-tertiary);
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 90px;
    position: relative;
    overflow: hidden;
}

.adsense-label {
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--text-muted);
    letter-spacing: 0.1em;
    margin-bottom: 0.5rem;
}

.adsense-mock-content {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-style: italic;
}

/* Banner sizes matching standard responsive units */
.adsense-banner-horizontal {
    width: 100%;
    max-width: 728px;
    height: 90px;
    margin: 2rem auto;
}

.adsense-sidebar-unit {
    width: 100%;
    min-height: 250px;
    margin: 1.5rem 0;
}

/* --- Back to Top Button --- */
#back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    background: var(--primary-gradient);
    color: white;
    border: none;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-all);
    z-index: 99;
}

#back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

#back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(79, 70, 229, 0.4);
}

#back-to-top svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

/* --- Cookie Consent Banner --- */
.cookie-consent-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: var(--bg-footer);
    color: var(--text-light);
    padding: 1.5rem 2rem;
    z-index: 1002;
    transform: translateY(100%);
    transition: transform 0.5s ease-in-out;
    box-shadow: 0 -10px 25px rgba(0, 0, 0, 0.3);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.cookie-consent-banner.show {
    transform: translateY(0);
}

.cookie-consent-container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 2rem;
}

.cookie-consent-text {
    font-size: 0.9375rem;
    line-height: 1.5;
}

.cookie-consent-text a {
    color: var(--accent-light);
    text-decoration: underline;
}

.cookie-consent-buttons {
    display: flex;
    gap: 1rem;
    flex-shrink: 0;
}

/* --- Footer --- */
footer.site-footer {
    background-color: var(--bg-footer);
    color: #94a3b8;
    padding: 4.5rem 0 2rem 0;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1.2fr 0.8fr 0.8fr 1.2fr;
    gap: 4rem;
}

.footer-brand h3 {
    color: var(--text-light);
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 1.5rem;
    margin-bottom: 1.25rem;
}

.footer-brand h3 span {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.footer-brand p {
    font-size: 0.9375rem;
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-link {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-md);
    background-color: rgba(255, 255, 255, 0.05);
    display: flex;
    justify-content: center;
    align-items: center;
    color: #94a3b8;
    transition: var(--transition-all);
}

.social-link:hover {
    background-color: var(--primary);
    color: var(--text-light);
    transform: translateY(-2px);
}

.social-link svg {
    width: 18px;
    height: 18px;
    fill: currentColor;
}

.footer-col h4 {
    color: var(--text-light);
    font-size: 1.05rem;
    margin-bottom: 1.5rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-link a {
    color: #94a3b8;
    font-size: 0.9375rem;
}

.footer-link a:hover {
    color: var(--text-light);
    padding-left: 0.25rem;
}

.footer-bottom {
    max-width: var(--max-width);
    margin: 4rem auto 0 auto;
    padding: 2rem 2rem 0 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
}

.footer-bottom-links {
    display: flex;
    gap: 1.5rem;
}

.footer-bottom-links a {
    color: #94a3b8;
}

.footer-bottom-links a:hover {
    color: var(--text-light);
}

/* --- Loader Animation --- */
.page-loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-primary);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.page-loader.hidden {
    opacity: 0;
    visibility: hidden;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary);
    border-radius: var(--radius-full);
    animation: spin 1s infinite linear;
}

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

/* --- Custom Sitemap Page Details --- */
.sitemap-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    padding: 3rem 0;
}

.sitemap-col h3 {
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
    margin-bottom: 1.25rem;
    font-size: 1.2rem;
    color: var(--primary);
}

.sitemap-links {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.sitemap-links a {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    display: block;
}

.sitemap-links a:hover {
    color: var(--primary);
    padding-left: 0.25rem;
}