@charset "UTF-8";

/* ===== CSS Variables ===== */
:root {
    --primary: #2D3748;
    --accent: #E53E3E;
    --accent-dark: #C53030;
    --bg: #FFFDF7;
    --surface: #FFF8F0;
    --border: #E8E0D4;
    --text: #2D3748;
    --text-light: #718096;
    --shadow-sm: 0 1px 3px rgba(45, 55, 72, 0.06), 0 1px 2px rgba(45, 55, 72, 0.04);
    --shadow-md: 0 4px 12px rgba(45, 55, 72, 0.08), 0 2px 6px rgba(45, 55, 72, 0.04);
    --shadow-lg: 0 10px 30px rgba(45, 55, 72, 0.10), 0 4px 12px rgba(45, 55, 72, 0.06);
    --shadow-xl: 0 20px 50px rgba(45, 55, 72, 0.12), 0 8px 20px rgba(45, 55, 72, 0.08);
    --radius: 2px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Reset ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: 'Noto Sans KR', sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.7;
    overflow-x: hidden;
    position: relative;
}

/* Paper texture background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    background-image:
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 50px,
            rgba(232, 224, 212, 0.15) 50px,
            rgba(232, 224, 212, 0.15) 51px
        ),
        repeating-linear-gradient(
            90deg,
            transparent,
            transparent 50px,
            rgba(232, 224, 212, 0.1) 50px,
            rgba(232, 224, 212, 0.1) 51px
        );
}

body > * {
    position: relative;
    z-index: 1;
}

/* ===== Utility ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ===== Fade-in animation ===== */
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

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

.fade-in-delay-1 { transition-delay: 0.1s; }
.fade-in-delay-2 { transition-delay: 0.2s; }
.fade-in-delay-3 { transition-delay: 0.3s; }
.fade-in-delay-4 { transition-delay: 0.4s; }

/* ===== HEADER ===== */
.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
}

.header::after {
    content: '';
    position: absolute;
    bottom: -3px;
    left: 0;
    width: 100%;
    height: 3px;
    background: repeating-linear-gradient(
        90deg,
        var(--border) 0px,
        var(--border) 8px,
        transparent 8px,
        transparent 12px
    );
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    font-family: 'Noto Serif KR', serif;
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--primary);
    text-decoration: none;
    letter-spacing: -0.02em;
    position: relative;
}

.logo::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--accent);
    transform: scaleX(0.6);
    transform-origin: left;
}

.nav {
    display: flex;
    align-items: center;
    gap: 0;
}

.nav-link {
    text-decoration: none;
    color: var(--text);
    font-size: 0.9rem;
    font-weight: 400;
    padding: 0.5rem 1.1rem;
    position: relative;
    transition: color var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 70%;
    height: 2px;
    background: var(--accent);
    transition: transform var(--transition);
}

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

.nav-link:hover::after {
    transform: translateX(-50%) scaleX(1);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.btn-ghost {
    background: none;
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.45rem 1rem;
    font-size: 0.82rem;
    font-family: inherit;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
}

.btn-ghost:hover {
    border-color: var(--primary);
    background: var(--primary);
    color: #fff;
}

.btn-accent {
    background: var(--accent);
    border: 1px solid var(--accent);
    color: #fff;
    padding: 0.45rem 1rem;
    font-size: 0.82rem;
    font-family: inherit;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
}

.btn-accent:hover {
    background: var(--accent-dark);
    border-color: var(--accent-dark);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 0.5rem;
    background: none;
    border: none;
}

.hamburger span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--primary);
    transition: all var(--transition);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile menu */
.mobile-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 1.5rem 2rem;
    box-shadow: var(--shadow-md);
}

.mobile-menu.open {
    display: block;
}

.mobile-menu .nav-link {
    display: block;
    padding: 0.75rem 0;
    font-size: 1rem;
}

.mobile-menu .header-actions {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

/* ===== HERO ===== */
.hero {
    padding: 6rem 0 5rem;
    min-height: 70vh;
    display: flex;
    align-items: center;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-left {
    position: relative;
    height: 380px;
}

.paper-card {
    position: absolute;
    background: #fff;
    padding: 2.5rem;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
}

.paper-card::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 0 40px 40px 0;
    border-color: transparent var(--bg) transparent transparent;
    filter: drop-shadow(-2px 2px 2px rgba(45, 55, 72, 0.06));
}

.paper-card::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, transparent 50%, var(--border) 50%);
    opacity: 0.5;
}

.paper-card-1 {
    top: 0;
    left: 0;
    width: 320px;
    z-index: 3;
    transform: rotate(-2deg);
    transition: transform var(--transition), box-shadow var(--transition);
}

.paper-card-1:hover {
    transform: rotate(-1deg) translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.paper-card-1 .card-title {
    font-family: 'Noto Serif KR', serif;
    font-size: 2rem;
    font-weight: 900;
    color: var(--primary);
    line-height: 1.3;
    letter-spacing: -0.03em;
}

.paper-card-2 {
    top: 80px;
    left: 140px;
    width: 280px;
    z-index: 2;
    transform: rotate(1.5deg);
    transition: transform var(--transition), box-shadow var(--transition);
}

.paper-card-2:hover {
    transform: rotate(2deg) translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.paper-card-2 .card-text {
    font-size: 0.9rem;
    color: var(--text-light);
    line-height: 1.8;
}

.paper-card-3 {
    bottom: 20px;
    left: 40px;
    width: 240px;
    z-index: 1;
    transform: rotate(-1deg);
    padding: 1.5rem;
    transition: transform var(--transition), box-shadow var(--transition);
}

.paper-card-3:hover {
    transform: rotate(0deg) translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.paper-card-3 .card-accent {
    display: inline-block;
    width: 40px;
    height: 4px;
    background: var(--accent);
    margin-bottom: 0.75rem;
}

.paper-card-3 .card-label {
    font-size: 0.78rem;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.hero-right {
    padding-left: 2rem;
}

.hero-right .subtitle {
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 1rem;
}

.hero-right .title {
    font-family: 'Noto Serif KR', serif;
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.4;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.hero-right .desc {
    font-size: 1rem;
    color: var(--text-light);
    line-height: 1.9;
    margin-bottom: 2.5rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.btn-primary-lg {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--primary);
    color: #fff;
    border: none;
    padding: 0.9rem 2rem;
    font-size: 0.92rem;
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}

.btn-primary-lg:hover {
    background: #1a202c;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-outline-lg {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: transparent;
    color: var(--primary);
    border: 1px solid var(--border);
    padding: 0.9rem 2rem;
    font-size: 0.92rem;
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition);
}

.btn-outline-lg:hover {
    border-color: var(--primary);
    background: var(--surface);
    transform: translateY(-2px);
}

/* ===== FEATURES ===== */
.features {
    padding: 5rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 3.5rem;
}

.section-header .label {
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 0.75rem;
}

.section-header .heading {
    font-family: 'Noto Serif KR', serif;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: -0.02em;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.75rem;
}

.feature-card {
    background: #fff;
    padding: 2rem 1.5rem;
    border: 1px solid var(--border);
    position: relative;
    overflow: hidden;
    transition: transform var(--transition), box-shadow var(--transition);
}

/* Folded corner effect */
.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 0 32px 32px 0;
    border-color: transparent var(--bg) transparent transparent;
    z-index: 2;
}

.feature-card::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, transparent 50%, rgba(232, 224, 212, 0.8) 50%);
    z-index: 1;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--surface);
    border: 1px solid var(--border);
    margin-bottom: 1.25rem;
    color: var(--accent);
    font-size: 1.2rem;
}

.feature-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 0.6rem;
}

.feature-desc {
    font-size: 0.85rem;
    color: var(--text-light);
    line-height: 1.7;
}

/* ===== BOARD WIDGETS ===== */
.boards {
    padding: 5rem 0;
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.boards-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.75rem;
}

.board-widget {
    background: #fff;
    border: 1px solid var(--border);
    padding: 1.75rem;
    position: relative;
    transition: transform var(--transition), box-shadow var(--transition);
}

.board-widget::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: var(--accent);
    opacity: 0;
    transition: opacity var(--transition);
}

.board-widget:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.board-widget:hover::before {
    opacity: 1;
}

.board-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
}

.board-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.board-title i {
    color: var(--accent);
    font-size: 0.85rem;
}

.board-more {
    font-size: 0.78rem;
    color: var(--text-light);
    text-decoration: none;
    transition: color var(--transition);
}

.board-more:hover {
    color: var(--accent);
}

.board-list {
    list-style: none;
}

.board-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 0;
    border-bottom: 1px dashed rgba(232, 224, 212, 0.6);
}

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

.board-item-title {
    font-size: 0.88rem;
    color: var(--text);
    text-decoration: none;
    transition: color var(--transition);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 75%;
}

.board-item-title:hover {
    color: var(--accent);
}

.board-item-date {
    font-size: 0.75rem;
    color: var(--text-light);
    flex-shrink: 0;
}

/* ===== STATS ===== */
.stats {
    padding: 5rem 0;
}

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

.stat-card {
    text-align: center;
    padding: 2.5rem 1.5rem;
    background: #fff;
    border: 1px solid var(--border);
    position: relative;
    transition: transform var(--transition), box-shadow var(--transition);
}

.stat-card::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 3px;
    background: var(--accent);
    transition: width var(--transition);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.stat-card:hover::after {
    width: 80px;
}

.stat-number {
    font-family: 'Noto Serif KR', serif;
    font-size: 2.5rem;
    font-weight: 900;
    color: var(--primary);
    margin-bottom: 0.25rem;
    letter-spacing: -0.02em;
}

.stat-suffix {
    font-size: 1.2rem;
    color: var(--accent);
    font-weight: 700;
}

.stat-label {
    font-size: 0.88rem;
    color: var(--text-light);
    margin-top: 0.25rem;
}

/* ===== CTA ===== */
.cta {
    padding: 5rem 0;
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.cta-card {
    max-width: 640px;
    margin: 0 auto;
    background: #fff;
    border: 1px solid var(--border);
    padding: 3.5rem;
    text-align: center;
    position: relative;
    box-shadow: var(--shadow-md);
}

.cta-card::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 0 50px 50px 0;
    border-color: transparent var(--surface) transparent transparent;
}

.cta-card::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, transparent 50%, var(--border) 50%);
    opacity: 0.5;
}

.cta-title {
    font-family: 'Noto Serif KR', serif;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.cta-desc {
    font-size: 0.95rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    line-height: 1.8;
}

.cta-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    background: var(--accent);
    color: #fff;
    border: none;
    padding: 1rem 2.5rem;
    font-size: 1rem;
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}

.cta-btn:hover {
    background: var(--accent-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===== FOOTER ===== */
.footer {
    padding: 3rem 0;
    background: var(--bg);
    border-top: 1px solid var(--border);
}

.footer-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.footer-logo {
    font-family: 'Noto Serif KR', serif;
    font-size: 1.2rem;
    font-weight: 900;
    color: var(--primary);
}

.footer-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-link {
    font-size: 0.85rem;
    color: var(--text-light);
    text-decoration: none;
    transition: color var(--transition);
}

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

.footer-copy {
    font-size: 0.78rem;
    color: var(--text-light);
    opacity: 0.7;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1023px) {
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

    .hero-left {
        height: 320px;
        max-width: 420px;
        margin: 0 auto;
    }

    .hero-right {
        padding-left: 0;
        text-align: center;
    }

    .hero-buttons {
        justify-content: center;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .boards-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 767px) {
    html {
        font-size: 15px;
    }

    .container {
        padding: 0 1.25rem;
    }

    .nav {
        display: none;
    }

    .header-actions .btn-ghost,
    .header-actions .btn-accent {
        display: none;
    }

    .hamburger {
        display: flex;
    }

    .hero {
        padding: 3.5rem 0 3rem;
        min-height: auto;
    }

    .hero-left {
        height: 280px;
        max-width: 340px;
    }

    .paper-card-1 {
        width: 240px;
        padding: 1.75rem;
    }

    .paper-card-1 .card-title {
        font-size: 1.5rem;
    }

    .paper-card-2 {
        width: 220px;
        left: 100px;
        padding: 1.5rem;
    }

    .paper-card-3 {
        width: 180px;
        left: 20px;
    }

    .hero-right .title {
        font-size: 1.6rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }

    .boards-grid {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }

    .cta-card {
        padding: 2.5rem 1.5rem;
    }

    .section-header .heading {
        font-size: 1.5rem;
    }

    .mobile-menu .header-actions {
        display: flex;
    }

    .mobile-menu .header-actions .btn-ghost,
    .mobile-menu .header-actions .btn-accent {
        display: inline-flex;
    }
}

@media (max-width: 359px) {
    html {
        font-size: 13px;
    }

    .hero-left {
        height: 240px;
        max-width: 280px;
    }

    .paper-card-1 {
        width: 200px;
        padding: 1.25rem;
    }

    .paper-card-2 {
        width: 180px;
        left: 80px;
        padding: 1.25rem;
    }

    .paper-card-3 {
        width: 150px;
    }
}

@media (min-width: 1920px) {
    html {
        font-size: 17px;
    }

    .container {
        max-width: 1320px;
    }
}

@media (min-width: 2560px) {
    html {
        font-size: 19px;
    }

    .container {
        max-width: 1600px;
    }
}