/* ==========================================================================
   YouTube Image Downloader - Core Design System & Glassmorphism Theme
   ========================================================================== */

:root {
    /* Color Tokens - Dark Mode (Default) */
    --bg-dark: #090D16;
    --bg-card: rgba(18, 26, 43, 0.75);
    --bg-card-hover: rgba(28, 39, 64, 0.85);
    --bg-input: rgba(15, 23, 42, 0.8);
    --border-color: rgba(255, 255, 255, 0.1);
    --border-highlight: rgba(99, 102, 241, 0.4);
    
    --text-primary: #F8FAFC;
    --text-secondary: #94A3B8;
    --text-muted: #64748B;
    
    --accent-red: #FF0033;
    --accent-indigo: #6366F1;
    --accent-cyan: #06B6D4;
    --accent-emerald: #10B981;
    
    --gradient-primary: linear-gradient(135deg, #FF0033 0%, #E11D48 50%, #7C3AED 100%);
    --gradient-glow: linear-gradient(135deg, rgba(255,0,51,0.2) 0%, rgba(99,102,241,0.2) 100%);
    --gradient-glass: linear-gradient(135deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.01) 100%);

    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-full: 9999px;
    
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.2);
    --shadow-glow: 0 0 25px rgba(255, 0, 51, 0.25);
    --shadow-card: 0 10px 30px -5px rgba(0, 0, 0, 0.4);

    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;

    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light Theme Overrides */
[data-theme="light"] {
    --bg-dark: #F8FAFC;
    --bg-card: rgba(255, 255, 255, 0.85);
    --bg-card-hover: rgba(255, 255, 255, 0.95);
    --bg-input: #FFFFFF;
    --border-color: rgba(0, 0, 0, 0.08);
    --border-highlight: rgba(99, 102, 241, 0.5);
    
    --text-primary: #0F172A;
    --text-secondary: #475569;
    --text-muted: #94A3B8;

    --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.08);
    --gradient-glass: linear-gradient(135deg, rgba(0, 0, 0, 0.02) 0%, rgba(0, 0, 0, 0.005) 100%);
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-image: 
        radial-gradient(circle at 15% 15%, rgba(255, 0, 51, 0.08) 0%, transparent 40%),
        radial-gradient(circle at 85% 85%, rgba(99, 102, 241, 0.08) 0%, transparent 40%);
}

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

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

button, input {
    font-family: inherit;
    outline: none;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    background: rgba(9, 13, 22, 0.85);
    border-bottom: 1px solid var(--border-color);
}
[data-theme="light"] .site-header {
    background: rgba(248, 250, 252, 0.85);
}

.header-container {
    max-width: 1240px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.brand-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    box-shadow: var(--shadow-glow);
}

.brand-name {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--text-primary) 30%, var(--accent-red) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 1.75rem;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.95rem;
    position: relative;
    padding: 0.5rem 0;
}

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

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-red);
    border-radius: 2px;
}

.theme-toggle-btn {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.theme-toggle-btn:hover {
    border-color: var(--accent-indigo);
    transform: scale(1.05);
}

.sun-icon { display: none; }
.moon-icon { display: block; }
[data-theme="light"] .sun-icon { display: block; }
[data-theme="light"] .moon-icon { display: none; }

/* ==========================================================================
   Hero & Input Section
   ========================================================================== */
.hero-section {
    padding: 4rem 1.5rem 2.5rem;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 1rem;
    border-radius: var(--radius-full);
    background: rgba(255, 0, 51, 0.1);
    border: 1px solid rgba(255, 0, 51, 0.2);
    color: var(--accent-red);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.hero-title {
    font-family: var(--font-heading);
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    max-width: 680px;
    margin: 0 auto 2.5rem;
}

/* Tool Input Box */
.tool-box-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(12px);
    position: relative;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

@media (min-width: 640px) {
    .input-group {
        flex-direction: row;
    }
}

.input-wrapper {
    flex: 1;
    position: relative;
}

.url-input {
    width: 100%;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 1rem 1.25rem 1rem 3rem;
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: var(--transition);
}

.url-input:focus {
    border-color: var(--accent-red);
    box-shadow: 0 0 0 3px rgba(255, 0, 51, 0.15);
}

.input-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}

.btn-fetch {
    background: var(--gradient-primary);
    color: white;
    font-weight: 700;
    font-size: 1rem;
    padding: 1rem 2rem;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: var(--transition);
    box-shadow: var(--shadow-glow);
    white-space: nowrap;
}

.btn-fetch:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(255, 0, 51, 0.4);
}

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

.input-examples {
    margin-top: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    flex-wrap: wrap;
}

.example-tag {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
}

.example-tag:hover {
    color: var(--accent-indigo);
    border-color: var(--accent-indigo);
}

/* ==========================================================================
   Results Grid & Cards
   ========================================================================== */
.results-container {
    max-width: 1240px;
    margin: 2rem auto;
    padding: 0 1.5rem;
    min-height: 50px;
}

.results-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.results-title {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
}

.cards-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 768px) {
    .cards-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .cards-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.asset-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.asset-card:hover {
    border-color: var(--border-highlight);
    transform: translateY(-4px);
    box-shadow: var(--shadow-card);
}

.asset-preview-box {
    width: 100%;
    aspect-ratio: 16 / 9;
    background: rgba(0, 0, 0, 0.4);
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.asset-preview-box.square {
    aspect-ratio: 1 / 1;
    max-height: 280px;
}

.asset-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.asset-card:hover .asset-img {
    transform: scale(1.05);
}

.res-badge {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    background: rgba(9, 13, 22, 0.85);
    backdrop-filter: blur(8px);
    color: var(--accent-cyan);
    border: 1px solid rgba(6, 182, 212, 0.3);
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.25rem 0.6rem;
    border-radius: var(--radius-sm);
}

.asset-body {
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.asset-title {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.asset-meta {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

.btn-download {
    margin-top: auto;
    width: 100%;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: var(--transition);
}

.btn-download:hover {
    background: var(--gradient-primary);
    border-color: transparent;
    color: white;
    box-shadow: var(--shadow-glow);
}

/* ==========================================================================
   AdSense Placement Containers
   ========================================================================== */
.ad-container {
    max-width: 1240px;
    margin: 2rem auto;
    padding: 0 1.5rem;
    text-align: center;
}

.ad-box {
    background: var(--bg-card);
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    min-height: 100px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.ad-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.ad-placeholder-msg {
    font-size: 0.82rem;
    color: var(--text-muted);
    text-align: center;
    padding: 0.75rem;
    line-height: 1.6;
}

.ad-placeholder-msg code {
    background: rgba(255,255,255,0.07);
    padding: 0.15rem 0.45rem;
    border-radius: 5px;
    font-size: 0.8rem;
    color: var(--accent-cyan);
}

/* ==========================================================================
   Content & Articles Layout
   ========================================================================== */
.content-section {
    max-width: 1000px;
    margin: 3rem auto;
    padding: 0 1.5rem;
}

.article-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-card);
}

.article-card h1, .article-card h2 {
    font-family: var(--font-heading);
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: 1.25rem;
}

.article-card h1 { font-size: 2.2rem; }
.article-card h2 { font-size: 1.6rem; margin-top: 2rem; }
.article-card h3 { font-size: 1.25rem; margin-top: 1.5rem; margin-bottom: 0.75rem; }

.article-card p {
    margin-bottom: 1.25rem;
    color: var(--text-secondary);
}

.article-card ul, .article-card ol {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
    color: var(--text-secondary);
}

.article-card li {
    margin-bottom: 0.5rem;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
    background: #050810;
    border-top: 1px solid rgba(255,255,255,0.12);
    margin-top: auto;
    padding: 3rem 1.5rem 1.5rem;
}

.footer-container {
    max-width: 1240px;
    margin: 0 auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2.5rem;
    margin-bottom: 2.5rem;
}

@media (min-width: 768px) {
    .footer-grid {
        grid-template-columns: 2fr 1fr 1fr 1fr;
    }
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 800;
    color: #FFFFFF;
    margin-bottom: 1rem;
}

.footer-desc {
    font-size: 0.9rem;
    color: #94A3B8;
    max-width: 340px;
    line-height: 1.65;
}

.footer-col h4 {
    font-family: var(--font-heading);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 1.1rem;
    color: #FFFFFF;
    opacity: 0.9;
}

.footer-col ul {
    list-style: none;
}

.footer-col li {
    margin-bottom: 0.65rem;
}

.footer-col a {
    font-size: 0.9rem;
    color: #CBD5E1;
    transition: var(--transition);
}

.footer-col a:hover {
    color: #FFFFFF;
    padding-left: 4px;
}

.footer-disclaimer {
    padding: 1.25rem 0;
    border-top: 1px solid rgba(255,255,255,0.1);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    font-size: 0.8rem;
    color: #94A3B8;
    line-height: 1.6;
}

.footer-bottom {
    padding-top: 1.5rem;
    text-align: center;
    font-size: 0.85rem;
    color: #94A3B8;
}

/* Spinner Loader */
.spinner {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

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

/* ==========================================================================
   Section Title & Subtitle
   ========================================================================== */
.links-section-header {
    margin-bottom: 2rem;
}

.section-title {
    font-family: var(--font-heading);
    font-size: 1.8rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

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

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* ==========================================================================
   Internal Links Card Grid
   ========================================================================== */
.internal-links-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

@media (min-width: 640px) {
    .internal-links-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1024px) {
    .internal-links-grid { grid-template-columns: repeat(3, 1fr); }
}

.link-card {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-left-width: 4px;
    border-radius: var(--radius-md);
    padding: 1.25rem;
    transition: var(--transition);
    text-decoration: none;
    position: relative;
}

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

.link-card--indigo { border-left-color: #6366F1; }
.link-card--cyan   { border-left-color: #06B6D4; }
.link-card--red    { border-left-color: #EF4444; }
.link-card--emerald{ border-left-color: #10B981; }
.link-card--amber  { border-left-color: #F59E0B; }
.link-card--purple { border-left-color: #8B5CF6; }

.link-card-icon {
    font-size: 1.6rem;
    line-height: 1;
    flex-shrink: 0;
    margin-top: 0.1rem;
}

.link-card-body {
    flex: 1;
}

.link-card-body h3 {
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.35rem;
    color: var(--text-primary);
}

.link-card-body p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin: 0;
}

.link-card-arrow {
    color: var(--text-muted);
    font-size: 1.1rem;
    transition: transform 0.3s ease;
    flex-shrink: 0;
    align-self: center;
}

.link-card:hover .link-card-arrow {
    transform: translateX(4px);
    color: var(--text-primary);
}

/* ==========================================================================
   External Links List
   ========================================================================== */
.external-links-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.ext-link-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem 1.25rem;
    transition: var(--transition);
    text-decoration: none;
}

.ext-link-row:hover {
    border-color: var(--border-highlight);
    transform: translateX(4px);
    background: var(--bg-card-hover);
}

.ext-link-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: white;
}

.ext-icon--red    { background: linear-gradient(135deg, #FF0033, #E11D48); }
.ext-icon--blue   { background: linear-gradient(135deg, #3B82F6, #2563EB); }
.ext-icon--orange { background: linear-gradient(135deg, #F97316, #EA580C); }
.ext-icon--green  { background: linear-gradient(135deg, #10B981, #059669); }
.ext-icon--cyan   { background: linear-gradient(135deg, #06B6D4, #0891B2); }
.ext-icon--indigo { background: linear-gradient(135deg, #6366F1, #4F46E5); }

.ext-link-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.ext-link-info strong {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
}

.ext-link-info span {
    font-size: 0.83rem;
    color: var(--text-secondary);
}

.ext-link-badge {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-muted);
    white-space: nowrap;
    border: 1px solid var(--border-color);
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-full);
    transition: var(--transition);
}

.ext-link-row:hover .ext-link-badge {
    color: var(--accent-indigo);
    border-color: var(--accent-indigo);
}

/* ==========================================================================
   FAQ Accordion
   ========================================================================== */
.faq-section .article-card {
    padding: 0;
    overflow: hidden;
}

.faq-list {
    display: flex;
    flex-direction: column;
}

.faq-item {
    border-bottom: 1px solid var(--border-color);
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: 1.35rem 1.75rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    cursor: pointer;
    text-align: left;
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 600;
    font-family: var(--font-body);
    transition: background 0.2s ease;
}

.faq-question:hover {
    background: rgba(255,255,255,0.03);
}

.faq-question[aria-expanded="true"] {
    background: rgba(99,102,241,0.06);
    color: #818CF8;
}

.faq-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    position: relative;
    transition: transform 0.35s cubic-bezier(0.4,0,0.2,1),
                border-color 0.3s ease,
                background 0.3s ease;
}

.faq-icon::before,
.faq-icon::after {
    content: '';
    position: absolute;
    background: currentColor;
    border-radius: 2px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.faq-icon::before { width: 10px; height: 2px; }
.faq-icon::after  { width: 2px;  height: 10px; transition: transform 0.35s cubic-bezier(0.4,0,0.2,1); }

.faq-question[aria-expanded="true"] .faq-icon {
    background: rgba(99,102,241,0.15);
    border-color: #6366F1;
    color: #6366F1;
}

.faq-question[aria-expanded="true"] .faq-icon::after {
    transform: translate(-50%, -50%) rotate(90deg);
    opacity: 0;
}

.faq-answer {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.38s cubic-bezier(0.4,0,0.2,1);
}

.faq-answer.is-open {
    grid-template-rows: 1fr;
}

.faq-answer-inner {
    overflow: hidden;
}

.faq-answer-inner p {
    padding: 0 1.75rem 1.35rem;
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

.faq-answer-inner a {
    color: var(--accent-indigo);
    text-decoration: underline;
    text-underline-offset: 3px;
}

.faq-answer-inner code {
    background: rgba(255,255,255,0.07);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85em;
    color: var(--accent-cyan);
}