* {
    box-sizing: border-box;
}

:root {
    --bg: #050608;
    --bg-alt: #0f111a;
    --text: #e8ebf1;
    --text-muted: #9ea6bf;
    --accent: #895cff;
    --accent2: #3db9ff;
    --card: rgba(18, 26, 45, .75);
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Roboto, 'Noto Sans KR', sans-serif;
    background: radial-gradient(circle at 20% 20%, #101525, var(--bg));
    color: var(--text);
}

.container {
    width: min(1200px, 96%);
    margin: 0 auto;
}

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    background: linear-gradient(180deg, rgba(5, 6, 8, 0.91), rgba(5, 6, 8, 0.5));
    border-bottom: 1px solid rgba(255, 255, 255, 0.07);
}

.header-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.3rem;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: #fff;
    text-decoration: none;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 1rem;
    margin: 0;
    padding: 0;
}

nav a {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s ease;
}

nav a:hover {
    color: var(--text);
}

.overlay {
    position: fixed;
    inset: 0;
    background: radial-gradient(circle at top, rgba(137, 92, 255, 0.2), transparent 30%),
                radial-gradient(circle at 80% 30%, rgba(61, 185, 255, 0.2), transparent 25%);
    pointer-events: none;
    z-index: 0;
}

.hero {
    min-height: 88vh;
    display: grid;
    place-items: center;
    text-align: center;
    padding: 8rem 0 5rem;
    background-image: linear-gradient(160deg, rgba(13, 22, 42, 0.92), rgba(5, 6, 8, 0.925));
}

.hero h1 {
    font-size: clamp(2rem, 4vw, 4.2rem);
    margin: 0 0 1rem;
    letter-spacing: 0.04em;
    line-height: 1.1;
}

.hero h1 span {
    display: block;
    color: var(--accent);
}

.hero p {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 780px;
    margin: 0 auto 1.8rem;
}

.hero-buttons {
    display: inline-flex;
    gap: .8rem;
}

.btn {
    border: 1px solid transparent;
    padding: 0.72rem 1.2rem;
    border-radius: 999px;
    font-weight: 700;
    display: inline-block;
    transition: all 0.25s ease;
    cursor: pointer;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(120deg, var(--accent), var(--accent2));
    color: #fff;
}

.btn-secondary {
    border-color: var(--text-muted);
    color: var(--text);
    backdrop-filter: blur(8px);
    background: rgba(255, 255, 255, 0.06);
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 12px 28px rgba(0, 0, 0, 0.35);
}

.section {
    padding: 5rem 0;
    position: relative;
    z-index: 1;
}

.section h2 {
    margin-bottom: 1rem;
    font-size: clamp(1.6rem, 3vw, 2.5rem);
}

.section p,
.section li {
    color: var(--text-muted);
}

.cards {
    margin-top: 1.6rem;
    display: grid;
    gap: 1.25rem;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.card {
    background: var(--card);
    border: 1px solid rgba(255, 255, 255, .12);
    border-radius: 18px;
    padding: 1.4rem;
    backdrop-filter: blur(8px);
}

.card h3 {
    color: #fff;
    margin-top: 0;
}

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

.roadmap li {
    background: rgba(255,255,255,.06);
    border-left: 4px solid var(--accent);
    padding: .9rem 1.1rem;
    border-radius: 8px;
    margin-bottom: .7rem;
}

.contact .social {
    display: flex;
    gap: .8rem;
    flex-wrap: wrap;
    margin-top: 0.8rem;
}

.contact .social a {
    color: var(--text);
    border: 1px solid rgba(158, 166, 191, 0.45);
    padding: .5rem .9rem;
    border-radius: 10px;
    text-decoration: none;
}

.footer {
    background: #050608;
    color: var(--text-muted);
    padding: 1.2rem 0;
    text-align: center;
}

@media (max-width: 768px) {
    .header-row { flex-direction: column; gap: .7rem; }
    nav ul { flex-wrap: wrap; justify-content: center; }
    .hero h1 { font-size: 2.4rem; }
}