* {
    box-sizing: border-box;
}
body {
    margin: 0;
    font-family: "PingFang SC", -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
    font-size: 16px;
    line-height: 1.65;
    color: #1e293b;
    background: #fff;
    -webkit-font-smoothing: antialiased;
}

/* Header */
.site-header {
    background: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
    color: #fff;
    padding: 0.85rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 24px rgba(0,0,0,0.12);
}
.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.75rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
    transition: opacity 0.2s ease;
}
.logo-link:hover {
    opacity: 0.92;
}
.logo-img {
    height: 40px;
    width: auto;
    display: block;
}
.nav a {
    color: rgba(255,255,255,0.88);
    text-decoration: none;
    margin-left: 2rem;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s ease;
}
.nav a:hover {
    color: #fff;
}

/* Hero */
.hero {
    background: linear-gradient(160deg, #0f172a 0%, #1e3a5f 45%, #2563eb 100%);
    color: #fff;
    padding: 4.5rem 1.5rem 5rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(ellipse 80% 50% at 50% -20%, rgba(59, 130, 246, 0.25), transparent);
    pointer-events: none;
}
.hero-inner {
    max-width: 640px;
    margin: 0 auto;
    position: relative;
}
.hero-logo {
    max-width: 200px;
    width: 100%;
    height: auto;
    margin: 0 auto 1.25rem;
    display: block;
    filter: drop-shadow(0 4px 12px rgba(0,0,0,0.15));
    animation: heroLogo 0.8s ease-out;
}
@keyframes heroLogo {
    from { opacity: 0; transform: translateY(-12px); }
    to { opacity: 1; transform: translateY(0); }
}
.hero h1 {
    margin: 0 0 1rem;
    font-size: 2.25rem;
    font-weight: 700;
    letter-spacing: 0.02em;
}
.hero-tagline {
    font-size: 1.2rem;
    margin: 0 0 0.75rem;
    opacity: 0.96;
    font-weight: 500;
}
.hero-desc {
    margin: 0 0 1.75rem;
    opacity: 0.9;
    font-size: 1.05rem;
    line-height: 1.7;
}
.btn {
    display: inline-block;
    padding: 0.75rem 1.75rem;
    border-radius: 10px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}
.btn:active {
    transform: scale(0.98);
}
.btn-primary {
    background: #fff;
    color: #2563eb;
    box-shadow: 0 4px 14px rgba(0,0,0,0.15);
}
.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(0,0,0,0.2);
    opacity: 0.98;
}
.btn-secondary {
    background: transparent;
    color: #fff;
    border: 2px solid rgba(255,255,255,0.5);
}
.btn-secondary:hover {
    background: rgba(255,255,255,0.1);
    border-color: rgba(255,255,255,0.8);
}

/* Sections */
.section {
    padding: 4rem 1.5rem;
}
.section-alt {
    background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%);
}
.container {
    max-width: 1100px;
    margin: 0 auto;
}
.section h2 {
    margin: 0 0 1rem;
    font-size: 1.9rem;
    font-weight: 700;
    text-align: center;
    color: #0f172a;
    letter-spacing: 0.02em;
}
.section-lead {
    text-align: center;
    max-width: 580px;
    margin: 0 auto 2.5rem;
    color: #475569;
    font-size: 1.05rem;
    line-height: 1.75;
}

/* Value list */
.value-list {
    max-width: 560px;
    margin: 0 auto;
    padding-left: 1.25rem;
    list-style: none;
}
.value-list li {
    margin-bottom: 0.85rem;
    padding-left: 0.5rem;
    color: #475569;
}
.value-list strong {
    color: #0f172a;
}

/* Cards */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.75rem;
    margin-top: 2.5rem;
}
.card {
    background: #fff;
    padding: 2rem;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(15, 23, 42, 0.06);
    border: 1px solid rgba(15, 23, 42, 0.06);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 32px rgba(15, 23, 42, 0.1);
}
.section-alt .card {
    background: #fff;
}
.card h3 {
    margin: 0 0 0.6rem;
    font-size: 1.2rem;
    font-weight: 600;
    color: #0f172a;
}
.card p {
    margin: 0;
    font-size: 0.95rem;
    color: #475569;
    line-height: 1.65;
}

/* CTA */
.cta {
    text-align: center;
}
.cta p {
    max-width: 500px;
    margin: 0 auto 1.25rem;
    color: #475569;
    font-size: 1.05rem;
}

/* Footer */
.site-footer {
    background: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
    color: rgba(255,255,255,0.85);
    padding: 2.5rem 1.5rem;
    text-align: center;
}
/* 若使用透明背景的 Logo（仅图形无白底），可在 footer 中放 <img src="images/logo.png" class="footer-logo">，并取消下面注释
.footer-logo {
    width: 120px;
    height: auto;
    margin: 0 auto 0.75rem;
    display: block;
    filter: brightness(0) invert(1);  /* 透明底 logo 时图形变白色，无白块 */
    opacity: 0.9;
}
*/
.footer-brand {
    margin: 0 0 0.25rem;
    font-weight: 600;
    color: #fff;
}
.footer-copy {
    margin: 0;
    font-size: 0.9rem;
}
.footer-icp {
    margin: 0.75rem 0 0;
    font-size: 0.85rem;
    opacity: 0.85;
}
.footer-icp a {
    color: rgba(255,255,255,0.9);
    text-decoration: none;
}
.footer-icp a:hover {
    text-decoration: underline;
}

/* Page header for inner pages */
.page-header {
    background: linear-gradient(160deg, #0f172a 0%, #1e3a5f 60%, #2563eb 100%);
    color: #fff;
    padding: 2.5rem 1.5rem;
    text-align: center;
}
.page-header h1 {
    margin: 0;
    font-size: 1.85rem;
    font-weight: 700;
}
.page-header p {
    margin: 0.5rem 0 0;
    opacity: 0.92;
    font-size: 0.98rem;
}

/* Content block */
.content-block {
    max-width: 720px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}
.content-block h2 {
    font-size: 1.4rem;
    margin: 2rem 0 0.75rem;
    color: #0f172a;
    font-weight: 600;
}
.content-block h2:first-child {
    margin-top: 0;
}
.content-block p, .content-block ul {
    margin: 0 0 1rem;
    color: #475569;
    line-height: 1.7;
}
.content-block ul {
    padding-left: 1.5rem;
}
.content-block .btn-secondary {
    background: #1e293b;
    color: #fff;
    border-color: #1e293b;
}
.content-block .btn-secondary:hover {
    background: #334155;
    border-color: #334155;
    opacity: 1;
}