:root {
    --bg: #ffffff;
    --bg-alt: #f6f8fb;
    --text: #1f2430;
    --text-soft: #5a6478;
    --primary: #3b6ef5;
    --primary-soft: #eaf0ff;
    --border: #e6e9f0;
    --card: #ffffff;
    --shadow: 0 6px 24px rgba(31, 36, 48, 0.08);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f1320;
        --bg-alt: #141a2b;
        --text: #e8ebf2;
        --text-soft: #9aa4bd;
        --primary: #6f9bff;
        --primary-soft: #1c2742;
        --border: #232b40;
        --card: #161d30;
        --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
        "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

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

/* NAV */
.nav {
    position: sticky;
    top: 0;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.9rem 5vw;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
}
.nav__brand { font-weight: 700; font-size: 1.15rem; color: var(--text); }
.nav__brand span { color: var(--primary); }
.nav__links { display: flex; gap: 1.4rem; font-size: 0.95rem; }
.nav__links a { color: var(--text-soft); }
.nav__links a:hover { color: var(--primary); text-decoration: none; }

/* HERO */
.hero {
    padding: 7rem 5vw 5rem;
    background: linear-gradient(160deg, var(--primary-soft), var(--bg) 70%);
}
.hero__inner { max-width: 880px; margin: 0 auto; text-align: center; }
.hero__eyebrow {
    text-transform: uppercase;
    letter-spacing: 0.12em;
    font-size: 0.8rem;
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 1rem;
}
.hero__title {
    font-size: clamp(3rem, 8vw, 5rem);
    line-height: 1.05;
    margin-bottom: 1.2rem;
    letter-spacing: -0.02em;
}
.hero__tagline {
    font-size: clamp(1.05rem, 2.4vw, 1.4rem);
    color: var(--text);
    max-width: 680px;
    margin: 0 auto 1rem;
}
.hero__tagline strong { color: var(--primary); }
.hero__sub { color: var(--text-soft); max-width: 600px; margin: 0 auto 2rem; }
.hero__cta { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

.btn {
    display: inline-block;
    padding: 0.7rem 1.5rem;
    border-radius: 999px;
    font-weight: 600;
    font-size: 0.95rem;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn--primary { background: var(--primary); color: #fff; box-shadow: var(--shadow); }
.btn--ghost { border: 1px solid var(--border); color: var(--text); }

/* SECTIONS */
.section { padding: 4.5rem 5vw; max-width: 980px; margin: 0 auto; }
.section--alt { background: var(--bg-alt); max-width: none; }
.section--alt > * { max-width: 980px; margin-left: auto; margin-right: auto; }
.section__title {
    font-size: 1.8rem;
    margin-bottom: 1.8rem;
    position: relative;
    padding-left: 0.9rem;
}
.section__title::before {
    content: "";
    position: absolute;
    left: 0; top: 0.25rem; bottom: 0.25rem;
    width: 4px;
    border-radius: 4px;
    background: var(--primary);
}
.prose p { color: var(--text-soft); margin-bottom: 1rem; }
.prose strong { color: var(--text); }
.placeholder { color: var(--text-soft); font-style: italic; }

/* TAGS */
.tags { list-style: none; display: flex; flex-wrap: wrap; gap: 0.7rem; }
.tags li {
    background: var(--primary-soft);
    color: var(--primary);
    padding: 0.45rem 1rem;
    border-radius: 999px;
    font-size: 0.9rem;
    font-weight: 500;
}

/* GRID / CARDS */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.3rem;
}
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    transition: transform 0.18s ease, box-shadow 0.18s ease;
}
.card:hover { transform: translateY(-4px); }
.card h3 { font-size: 1.05rem; margin-bottom: 0.6rem; word-break: break-word; }
.card p { color: var(--text-soft); font-size: 0.92rem; flex: 1; margin-bottom: 1rem; }
.card__link { font-weight: 600; font-size: 0.9rem; }

/* CONTACT */
.contact { list-style: none; display: grid; gap: 0.9rem; max-width: 520px; }
.contact li {
    display: flex;
    gap: 1rem;
    padding: 0.8rem 1.2rem;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
}
.contact span {
    width: 130px;
    color: var(--text-soft);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* FOOTER */
.footer {
    text-align: center;
    padding: 2.5rem 5vw;
    color: var(--text-soft);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
}

@media (max-width: 600px) {
    .nav__links { gap: 0.9rem; font-size: 0.85rem; }
    .section { padding: 3rem 6vw; }
    .contact li { flex-direction: column; gap: 0.2rem; }
    .contact span { width: auto; }
}

/* Navigation and keyboard access on narrow screens. */
html { scroll-padding-top: 6rem; }
a:focus-visible { outline: 3px solid var(--primary); outline-offset: 4px; }
.skip-link { position: absolute; left: 1rem; top: -5rem; z-index: 20; background: var(--bg); padding: .7rem; }
.skip-link:focus { top: 1rem; }
@media (max-width: 600px) {
    .nav { flex-wrap: wrap; gap: .5rem; }
    .nav__links { flex-wrap: wrap; gap: .6rem 1rem; }
    .grid { grid-template-columns: minmax(0, 1fr); }
    .contact a { overflow-wrap: anywhere; }
}
@media (prefers-reduced-motion: reduce) {
    .btn, .card { transition: none; }
    .btn:hover, .card:hover { transform: none; }
}