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

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: #1a1a2e;
    background: #fff;
    font-size: 15px;
    line-height: 1.6;
}

a { text-decoration: none; color: inherit; }

img { max-width: 100%; height: auto; display: block; }

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ── Navbar ── */
.navbar {
    background: #fff;
    border-bottom: 1px solid #eaeaef;
    position: sticky;
    top: 0;
    z-index: 100;
    height: 60px;
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 17px;
    font-weight: 600;
    color: #1a1a2e;
}

.nav-logo {
    width: 32px;
    height: 32px;
    border-radius: 6px;
}

.nav-links {
    display: flex;
    gap: 28px;
}

.nav-links a {
    font-size: 15px;
    color: #555;
    padding: 6px 0;
    border-bottom: 2px solid transparent;
    transition: color .2s, border-color .2s;
}

.nav-links a:hover {
    color: #4361ee;
    border-bottom-color: #4361ee;
}

/* ── Buttons ── */
.btn {
    display: inline-block;
    padding: 13px 28px;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 500;
    transition: background .2s, box-shadow .2s, transform .15s;
}

.btn-primary {
    background: #4361ee;
    color: #fff;
}

.btn-primary:hover {
    background: #3a56d4;
    box-shadow: 0 4px 14px rgba(67, 97, 238, .28);
    transform: translateY(-1px);
}

.btn-outline {
    background: #f0f4ff;
    color: #4361ee;
    border: 1px solid #d5ddf6;
}

.btn-outline:hover {
    background: #e4ebff;
    border-color: #4361ee;
}

.btn-full {
    display: block;
    width: 100%;
    text-align: center;
}

.btn-hint {
    display: block;
    text-align: center;
    font-size: 12px;
    color: #999;
    margin-top: 8px;
}

/* ── Hero (index) ── */
.hero {
    text-align: center;
    padding: 80px 0 56px;
    background: linear-gradient(168deg, #f0f4ff 0%, #fff 60%);
}

.hero h1 {
    font-size: 48px;
    font-weight: 700;
    color: #1a1a2e;
    margin-bottom: 16px;
}

.hero-desc {
    font-size: 18px;
    color: #555;
    max-width: 620px;
    margin: 0 auto 36px;
}

.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-bottom: 14px;
}

.hero-hint {
    font-size: 13px;
    color: #999;
    margin-bottom: 18px;
}

.hero-link {
    font-size: 14px;
    color: #4361ee;
}

.hero-link:hover { color: #3a56d4; }

/* ── Reviews ── */
.reviews {
    padding: 70px 0;
    background: #fff;
}

.reviews h2,
.knowledge h2 {
    text-align: center;
    font-size: 28px;
    font-weight: 600;
    color: #1a1a2e;
    margin-bottom: 40px;
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.review-card {
    background: #fafbff;
    border: 1px solid #eaeaef;
    border-radius: 12px;
    padding: 28px 24px;
}

.review-stars {
    color: #f5a623;
    font-size: 18px;
    margin-bottom: 14px;
    letter-spacing: 2px;
}

.review-text {
    font-size: 14px;
    color: #444;
    line-height: 1.75;
    margin-bottom: 20px;
}

.review-user {
    display: flex;
    align-items: center;
    gap: 12px;
}

.review-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
}

.review-name {
    font-size: 14px;
    font-weight: 500;
    color: #1a1a2e;
}

.review-meta {
    font-size: 12px;
    color: #999;
}

/* ── Knowledge Cards ── */
.knowledge {
    padding: 70px 0;
    background: #f7f8fc;
}

.knowledge-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.knowledge-card {
    background: #fff;
    border: 1px solid #eaeaef;
    border-radius: 10px;
    padding: 24px 28px;
    transition: box-shadow .2s;
}

.knowledge-card:hover {
    box-shadow: 0 4px 18px rgba(0, 0, 0, .06);
}

.knowledge-card h3 {
    font-size: 16px;
    font-weight: 600;
    color: #1a1a2e;
    margin-bottom: 10px;
}

.knowledge-card p {
    font-size: 14px;
    color: #555;
    line-height: 1.8;
}

/* ── Download Hero ── */
.dl-hero {
    text-align: center;
    padding: 64px 0 36px;
    background: linear-gradient(168deg, #f0f4ff 0%, #fff 60%);
}

.dl-hero h1 {
    font-size: 30px;
    font-weight: 700;
    color: #1a1a2e;
    margin-bottom: 12px;
}

.dl-hero-desc {
    font-size: 16px;
    color: #666;
}

/* ── Platform Cards ── */
.platforms {
    padding: 36px 0 80px;
}

.platform-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(310px, 1fr));
    gap: 24px;
}

.platform-card {
    background: #fff;
    border: 1px solid #eaeaef;
    border-radius: 12px;
    padding: 32px 28px;
    transition: box-shadow .2s, border-color .2s;
}

.platform-card:hover {
    border-color: #4361ee;
    box-shadow: 0 6px 24px rgba(67, 97, 238, .1);
}

.platform-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.platform-head h2 {
    font-size: 22px;
    font-weight: 600;
    color: #1a1a2e;
}

.badge {
    font-size: 11px;
    background: #4361ee;
    color: #fff;
    padding: 3px 10px;
    border-radius: 20px;
    font-weight: 500;
}

.platform-version {
    font-size: 13px;
    color: #999;
    margin-bottom: 4px;
}

.platform-req {
    font-size: 13px;
    color: #777;
    margin-bottom: 20px;
}

.variants {
    margin-top: 14px;
    text-align: center;
    font-size: 13px;
}

.variant {
    color: #4361ee;
    transition: color .2s;
}

.variant:hover {
    color: #3a56d4;
    text-decoration: underline;
}

.variant-sep {
    color: #ccc;
    margin: 0 6px;
}

/* ── Footer ── */
.footer {
    background: #1a1a2e;
    color: #bbb;
    padding: 48px 0 32px;
    text-align: center;
}

.footer-disclaimer {
    margin-bottom: 20px;
}

.footer-disclaimer p {
    font-size: 13px;
    color: #999;
    line-height: 1.9;
}

.footer-copy {
    font-size: 12px;
    color: #666;
}

/* ── Responsive ── */
@media (max-width: 900px) {
    .reviews-grid { grid-template-columns: 1fr; }
    .knowledge-grid { grid-template-columns: 1fr; }
    .platform-cards { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
    .hero { padding: 50px 0 40px; }
    .hero h1 { font-size: 32px; }
    .hero-desc { font-size: 16px; }
    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
        padding: 0 12px;
    }
    .btn { text-align: center; }
    .dl-hero h1 { font-size: 22px; }
    .reviews h2, .knowledge h2 { font-size: 24px; }
    .nav-brand span { font-size: 15px; }
}