html {
    scroll-behavior: smooth;
}

body {
    background:
        radial-gradient(circle at top left, rgba(14, 165, 233, 0.08), transparent 30%),
        radial-gradient(circle at 85% 15%, rgba(249, 115, 22, 0.08), transparent 24%),
        #f8fafc;
}

.grain {
    opacity: 0.22;
    background-image:
        linear-gradient(rgba(15, 23, 42, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(15, 23, 42, 0.03) 1px, transparent 1px);
    background-size: 28px 28px;
    mask-image: radial-gradient(circle at center, black, transparent 80%);
}

.hero-bg {
    background:
        radial-gradient(circle at 20% 20%, rgba(14, 165, 233, 0.14), transparent 28%),
        radial-gradient(circle at 82% 30%, rgba(249, 115, 22, 0.12), transparent 24%),
        linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(248, 250, 252, 0.6));
}

.section-kicker {
    margin-bottom: 1rem;
    color: #0ea5e9;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.24em;
    text-transform: uppercase;
}

.section-kicker-dark {
    color: #7dd3fc;
}

.section-title {
    max-width: 52rem;
    font-size: clamp(2rem, 4vw, 3.5rem);
    line-height: 1;
    font-weight: 700;
    letter-spacing: -0.04em;
    color: #0f172a;
}

.tag {
    border: 1px solid #cbd5e1;
    border-radius: 9999px;
    background: rgba(255, 255, 255, 0.8);
    padding: 0.5rem 0.8rem;
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1.25rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: #0369a1;
    transition: color 180ms ease;
}

.project-link:hover {
    color: #0f172a;
}

.timeline-card {
    display: grid;
    gap: 1.25rem;
    border: 1px solid #e2e8f0;
    border-radius: 1.75rem;
    background: rgba(255, 255, 255, 0.88);
    padding: 1.75rem;
    box-shadow: 0 20px 60px rgba(15, 23, 42, 0.06);
}

.timeline-meta {
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: #0ea5e9;
}

.timeline-title {
    font-size: 1.35rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    color: #0f172a;
}

.timeline-copy {
    margin-top: 0.75rem;
    max-width: 50rem;
    color: #475569;
    line-height: 1.9;
}

.contact-link {
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
    border-radius: 9999px;
    border: 1px solid #e2e8f0;
    background: white;
    padding: 0.9rem 1.1rem;
    color: #0f172a;
    transition: transform 180ms ease, border-color 180ms ease, color 180ms ease;
}

.contact-link:hover {
    transform: translateY(-2px);
    border-color: #7dd3fc;
    color: #0369a1;
}

.contact-icon {
    width: 1.25rem;
    height: 1.25rem;
    flex: 0 0 auto;
}

.lang-toggle {
    position: relative;
}

.lang-btn {
    color: #475569;
    transition: background-color 180ms ease, color 180ms ease;
}

.lang-btn.active {
    background: #0f172a;
    color: white;
}

html .lang-ko {
    display: none;
}

html .lang-en {
    display: inline;
}

html[lang="en"] .lang-ko {
    display: none;
}

html[lang="ko"] .lang-ko {
    display: inline;
}

html[lang="ko"] .lang-en {
    display: none;
}

::-webkit-scrollbar {
    width: 9px;
    height: 9px;
}

::-webkit-scrollbar-track {
    background: #f8fafc;
}

::-webkit-scrollbar-thumb {
    background: #94a3b8;
    border-radius: 9999px;
}

::-webkit-scrollbar-thumb:hover {
    background: #64748b;
}

@media (min-width: 768px) {
    .timeline-card {
        grid-template-columns: 140px minmax(0, 1fr);
        align-items: start;
    }
}