:root {
    --bg: #0f1720;
    --surface: #16212e;
    --surface-2: #1d2b3a;
    --text: #e6edf3;
    --muted: #8b9bb0;
    --accent: #2dd4bf;
    --accent-2: #38bdf8;
    --danger: #f87171;
    --border: #243447;
    --radius: 12px;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, "Segoe UI", "PingFang TC", "Microsoft JhengHei", sans-serif;
    background: radial-gradient(1200px 600px at 80% -10%, #14303a, var(--bg));
    color: var(--text);
    line-height: 1.6;
}

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

.site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 24px;
    background: rgba(13, 20, 28, 0.7);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
}
.brand { font-weight: 700; font-size: 1.2rem; color: var(--text); }
.site-header nav a { margin-left: 18px; color: var(--muted); }
.site-header nav a:hover { color: var(--text); }

.container { max-width: 960px; margin: 0 auto; padding: 40px 24px; }

.hero { text-align: center; padding: 48px 0; }
.hero h1 { font-size: 2.4rem; margin: 0 0 12px; }
.hero p { color: var(--muted); font-size: 1.1rem; }
.actions { margin-top: 24px; }

.btn {
    display: inline-block;
    padding: 12px 24px;
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    color: #06222b;
    font-weight: 600;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 1rem;
}
.btn:hover { filter: brightness(1.08); text-decoration: none; }

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 18px;
    margin-top: 32px;
}
.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
}
.card h3 { margin-top: 0; }
.card p { color: var(--muted); margin-bottom: 0; }
.card.stat { text-align: center; }
.card.stat .num { display: block; font-size: 2.6rem; font-weight: 700; color: var(--accent); }
.card.stat .label { color: var(--muted); }

.auth { max-width: 380px; margin: 40px auto; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 32px; }
.auth h1 { margin-top: 0; text-align: center; }

.form { display: flex; flex-direction: column; gap: 16px; }
.form label { display: flex; flex-direction: column; gap: 6px; color: var(--muted); font-size: 0.9rem; }
.form input {
    padding: 11px 12px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    font-size: 1rem;
}
.form input:focus { outline: none; border-color: var(--accent); }

.alert { padding: 10px 14px; border-radius: 8px; margin: 0 0 16px; }
.alert.error { background: rgba(248, 113, 113, 0.12); color: var(--danger); border: 1px solid rgba(248,113,113,0.3); }
.hint { color: var(--muted); font-size: 0.85rem; text-align: center; margin-top: 16px; }

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