/* ============================================
   CakCuk-eun — Website Styles
   Dark Premium Academic Theme
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
    --bg-primary: #0a0a0a;
    --bg-secondary: #111111;
    --bg-tertiary: #1a1a1a;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-hover: rgba(255, 255, 255, 0.06);

    --text-primary: #f0f0f0;
    --text-secondary: #a0a0a0;
    --text-muted: #666666;

    --accent: #c8a45c;
    --accent-light: #e8c97c;
    --accent-dark: #9e7d3a;
    --accent-glow: rgba(200, 164, 92, 0.15);

    --border: rgba(255, 255, 255, 0.08);
    --border-accent: rgba(200, 164, 92, 0.3);

    --glass-bg: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.06);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

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

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;

    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition);
}
a:hover {
    color: var(--accent-light);
}

code {
    background: rgba(200, 164, 92, 0.12);
    color: var(--accent-light);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.9em;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
}

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

::selection {
    background: var(--accent);
    color: var(--bg-primary);
}

/* ---------- Container ---------- */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ---------- Navbar ---------- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: all var(--transition);
    background: transparent;
}

.navbar.scrolled {
    padding: 10px 0;
    background: rgba(10, 10, 10, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    font-weight: 800;
    text-decoration: none;
    letter-spacing: 1px;
}

.logo-cakcuk,
.title-cakcuk {
    color: var(--text-primary);
}

.logo-eun,
.title-eun {
    color: var(--accent);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 8px;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    transition: all var(--transition);
    text-decoration: none;
}

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

.nav-link.active {
    color: var(--accent);
}

/* Mobile hamburger */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    z-index: 1001;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition);
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}
.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}
.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ---------- Hero ---------- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
    padding: 120px 24px 80px;
}

.hero-bg-overlay {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at 20% 50%, var(--accent-glow) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(200, 164, 92, 0.08) 0%, transparent 40%),
        linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    z-index: 0;
}

.hero-particles {
    position: absolute;
    inset: 0;
    z-index: 1;
    pointer-events: none;
}

.hero-particles .particle {
    position: absolute;
    width: 2px;
    height: 2px;
    background: var(--accent);
    border-radius: 50%;
    opacity: 0;
    animation: particleFloat 8s infinite;
}

@keyframes particleFloat {
    0% { opacity: 0; transform: translateY(0) scale(1); }
    10% { opacity: 0.6; }
    90% { opacity: 0; }
    100% { opacity: 0; transform: translateY(-150px) scale(0.5); }
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 700px;
}

.hero-label {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 4px;
    margin-bottom: 20px;
}

.hero-title {
    font-family: var(--font-heading);
    font-size: clamp(3rem, 8vw, 5.5rem);
    font-weight: 800;
    letter-spacing: 3px;
    line-height: 1.1;
    margin-bottom: 16px;
}

.hero-tagline {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    letter-spacing: 1px;
}

.hero-description {
    font-size: 1.05rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* Scroll indicator */
.hero-scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    z-index: 2;
}

.hero-scroll-indicator span {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 3px;
}

.scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--accent), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 1; transform: scaleY(1); }
    50% { opacity: 0.3; transform: scaleY(0.6); }
}

/* ---------- Buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    border-radius: var(--radius-sm);
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent), var(--accent-dark));
    color: var(--bg-primary);
    box-shadow: 0 4px 20px rgba(200, 164, 92, 0.25);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--accent-light), var(--accent));
    color: var(--bg-primary);
    box-shadow: 0 6px 30px rgba(200, 164, 92, 0.4);
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-glow);
    transform: translateY(-2px);
}

.btn-large {
    padding: 18px 40px;
    font-size: 1.05rem;
}

/* ---------- Sections ---------- */
.section {
    padding: 100px 0;
    position: relative;
}

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

.section-header {
    margin-bottom: 60px;
    position: relative;
}

.section-number {
    font-family: var(--font-heading);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--accent);
    letter-spacing: 2px;
    display: block;
    margin-bottom: 8px;
}

.section-title {
    font-family: var(--font-heading);
    font-size: clamp(2rem, 4vw, 2.8rem);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.section-line {
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), transparent);
    border-radius: 2px;
}

.section-intro {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin-bottom: 48px;
    line-height: 1.8;
}

/* ---------- Glass Card ---------- */
.glass-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 32px;
    transition: all var(--transition);
}

.glass-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-accent);
    box-shadow: var(--glass-shadow);
}

/* ---------- About Grid ---------- */
.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.about-card-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-sm);
    background: var(--accent-glow);
    border: 1px solid var(--border-accent);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: var(--accent);
}

.about-card h3 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.about-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* ---------- Features Grid ---------- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 48px;
}

.feature-card {
    text-align: center;
    padding: 40px 28px;
}

.feature-icon {
    color: var(--accent);
    margin-bottom: 20px;
}

.feature-card h3 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* ---------- Specs Table ---------- */
.specs-table-wrapper {
    overflow-x: auto;
}

.specs-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.specs-table th,
.specs-table td {
    padding: 16px 24px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.specs-table th {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--accent);
    background: rgba(200, 164, 92, 0.05);
}

.specs-table td {
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.specs-table td:first-child {
    font-weight: 500;
    color: var(--text-primary);
}

.specs-table tr:last-child td {
    border-bottom: none;
}

/* ---------- Documentation ---------- */
.docs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-bottom: 48px;
}

.doc-card {
    position: relative;
    padding-top: 40px;
}

.doc-step {
    position: absolute;
    top: -1px;
    left: 32px;
    font-family: var(--font-heading);
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--bg-primary);
    background: var(--accent);
    padding: 4px 14px;
    border-radius: 0 0 var(--radius-sm) var(--radius-sm);
    letter-spacing: 1px;
}

.doc-card h3 {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.doc-card ol,
.doc-card ul {
    padding-left: 20px;
    color: var(--text-secondary);
    font-size: 0.92rem;
}

.doc-card li {
    margin-bottom: 8px;
    line-height: 1.6;
}

.doc-download {
    text-align: center;
    padding: 40px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
}

.doc-note {
    margin-top: 16px;
    font-size: 0.85rem;
    color: var(--text-muted);
    font-style: italic;
}

/* ---------- Download Section ---------- */
.download-card {
    max-width: 700px;
    margin: 0 auto;
    padding: 40px;
}

.download-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 32px;
    flex-wrap: wrap;
    gap: 16px;
}

.download-version h3 {
    font-family: var(--font-heading);
    font-size: 1.6rem;
    font-weight: 700;
    margin: 8px 0 4px;
}

.version-badge {
    display: inline-block;
    background: var(--accent);
    color: var(--bg-primary);
    padding: 3px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    font-family: var(--font-heading);
    letter-spacing: 1px;
}

.version-date {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.format-tag {
    display: inline-block;
    border: 1px solid var(--accent);
    color: var(--accent);
    padding: 6px 18px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 600;
    font-family: var(--font-heading);
    letter-spacing: 2px;
}

.download-specs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
    margin-bottom: 32px;
    padding: 24px;
    background: rgba(200, 164, 92, 0.04);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
}

.spec-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.spec-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 500;
}

.spec-value {
    font-size: 0.95rem;
    color: var(--text-primary);
    font-weight: 500;
}

.download-card .btn-large {
    width: 100%;
    justify-content: center;
    margin-bottom: 32px;
}

.changelog {
    border-top: 1px solid var(--border);
    padding-top: 24px;
}

.changelog h4 {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 16px;
}

.changelog-entry {
    padding-left: 20px;
    border-left: 2px solid var(--accent);
}

.changelog-version {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
    margin-bottom: 4px;
}

.changelog-date {
    color: var(--text-muted);
    font-weight: 400;
}

.changelog-label {
    display: inline-block;
    font-size: 0.8rem;
    color: var(--accent);
    font-weight: 500;
    margin-bottom: 8px;
}

.changelog-entry ul {
    padding-left: 20px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.changelog-entry li {
    margin-bottom: 4px;
}

/* ---------- License / IP ---------- */
.license-content {
    display: grid;
    gap: 24px;
    max-width: 800px;
}

.ip-statement {
    border-left: 3px solid var(--accent);
}

.ip-statement h3 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.ip-subtitle {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 20px;
}

.ip-statement blockquote {
    margin: 0;
    padding: 0;
}

.ip-statement blockquote p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
    margin-bottom: 16px;
}

.ip-statement blockquote p:last-child {
    margin-bottom: 0;
}

.terms h3 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.terms ul {
    list-style: none;
    padding: 0;
}

.terms li {
    color: var(--text-secondary);
    font-size: 0.95rem;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
    padding-left: 20px;
    position: relative;
}

.terms li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent);
}

.terms li:last-child {
    border-bottom: none;
}

/* ---------- FAQ ---------- */
.faq-list {
    max-width: 750px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    padding: 0;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 28px;
    background: none;
    border: none;
    cursor: pointer;
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    text-align: left;
    transition: color var(--transition);
}

.faq-question:hover {
    color: var(--accent);
}

.faq-chevron {
    color: var(--text-muted);
    transition: transform var(--transition);
    flex-shrink: 0;
    margin-left: 16px;
}

.faq-item.open .faq-chevron {
    transform: rotate(180deg);
    color: var(--accent);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    padding: 0 28px;
}

.faq-item.open .faq-answer {
    max-height: 300px;
    padding: 0 28px 24px;
}

.faq-answer p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* ---------- Contact ---------- */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 24px;
    align-items: start;
}

.contact-info h3,
.contact-form h3 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.contact-info p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 24px;
}

.contact-method {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--accent);
}

.contact-method a {
    font-weight: 500;
    word-break: break-all;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.95rem;
    transition: border-color var(--transition), box-shadow var(--transition);
    outline: none;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

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

.contact-form .btn {
    width: 100%;
    justify-content: center;
}

/* ---------- Footer ---------- */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 48px 0 24px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 32px;
    flex-wrap: wrap;
    gap: 24px;
}

.footer-brand {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    font-weight: 800;
    letter-spacing: 1px;
}

.footer-tagline {
    font-family: var(--font-body);
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 400;
    margin-top: 6px;
    font-style: italic;
    letter-spacing: 0;
}

.footer-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-muted);
    font-size: 0.85rem;
    transition: color var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid var(--border);
    padding-top: 24px;
    text-align: center;
}

.footer-bottom p {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ---------- Scroll Animations ---------- */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease-out, transform 0.7s ease-out;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger delays for grid items */
.about-grid .animate-on-scroll:nth-child(2) { transition-delay: 0.1s; }
.about-grid .animate-on-scroll:nth-child(3) { transition-delay: 0.2s; }

.features-grid .animate-on-scroll:nth-child(2) { transition-delay: 0.1s; }
.features-grid .animate-on-scroll:nth-child(3) { transition-delay: 0.2s; }
.features-grid .animate-on-scroll:nth-child(4) { transition-delay: 0.3s; }

.docs-grid .animate-on-scroll:nth-child(2) { transition-delay: 0.1s; }
.docs-grid .animate-on-scroll:nth-child(3) { transition-delay: 0.2s; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
    .contact-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    html {
        scroll-padding-top: 70px;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: rgba(15, 15, 15, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 80px 32px 32px;
        gap: 4px;
        transition: right var(--transition);
        border-left: 1px solid var(--border);
    }

    .nav-menu.active {
        right: 0;
    }

    .nav-link {
        font-size: 1rem;
        padding: 12px 16px;
    }

    .hero {
        padding: 100px 20px 60px;
        min-height: 90vh;
    }

    .hero-title {
        font-size: clamp(2.5rem, 10vw, 3.5rem);
    }

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

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

    .hero-scroll-indicator {
        display: none;
    }

    .section {
        padding: 72px 0;
    }

    .section-header {
        margin-bottom: 40px;
    }

    .about-grid,
    .features-grid,
    .docs-grid {
        grid-template-columns: 1fr;
    }

    .download-card {
        padding: 28px;
    }

    .download-header {
        flex-direction: column;
    }

    .glass-card {
        padding: 24px;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

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

@media (max-width: 400px) {
    .btn {
        padding: 12px 20px;
        font-size: 0.9rem;
    }

    .hero-title {
        font-size: 2.2rem;
    }
}