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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: #2c3e50;
    background: #ffffff;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

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

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

/* Header */
.site-header {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid #eef0f3;
    z-index: 100;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 18px;
}

.logo-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 8px;
    background: linear-gradient(135deg, #6a8dff, #9b6bff);
    color: #fff;
    font-weight: 700;
}

.nav a {
    margin-left: 28px;
    color: #4a5568;
    font-size: 15px;
    transition: color 0.2s;
}

.nav a:hover {
    color: #6a8dff;
}

/* Hero */
.hero {
    padding: 96px 0 72px;
    background: linear-gradient(135deg, #f5f7ff 0%, #fdf5ff 100%);
    text-align: center;
}

.hero h1 {
    font-size: 44px;
    line-height: 1.25;
    font-weight: 800;
    color: #1a202c;
    margin-bottom: 20px;
}

.hero .subtitle {
    font-size: 17px;
    color: #4a5568;
    max-width: 640px;
    margin: 0 auto 36px;
}

.hero-actions {
    display: flex;
    gap: 14px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 12px 26px;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 500;
    transition: transform 0.15s, box-shadow 0.15s, background 0.2s;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, #6a8dff, #9b6bff);
    color: #fff;
    box-shadow: 0 6px 18px rgba(106, 141, 255, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 24px rgba(106, 141, 255, 0.45);
}

.btn-ghost {
    background: #fff;
    color: #4a5568;
    border: 1px solid #e2e8f0;
}

.btn-ghost:hover {
    color: #6a8dff;
    border-color: #6a8dff;
}

/* Section */
.section {
    padding: 72px 0;
}

.section-alt {
    background: #fafbfd;
}

.section-title {
    font-size: 30px;
    font-weight: 700;
    color: #1a202c;
    margin-bottom: 10px;
    text-align: center;
}

.section-desc {
    text-align: center;
    color: #718096;
    margin-bottom: 44px;
}

/* Card grid */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 22px;
}

.card {
    padding: 26px 24px;
    background: #fff;
    border: 1px solid #eef0f3;
    border-radius: 12px;
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 28px rgba(0, 0, 0, 0.06);
    border-color: #d9e0ff;
}

.card-tag {
    display: inline-block;
    padding: 3px 10px;
    background: #eef2ff;
    color: #6a8dff;
    font-size: 12px;
    border-radius: 4px;
    margin-bottom: 12px;
}

.card h3 {
    font-size: 18px;
    color: #1a202c;
    margin-bottom: 10px;
}

.card p {
    color: #4a5568;
    font-size: 14.5px;
    margin-bottom: 14px;
}

.card-date {
    font-size: 13px;
    color: #a0aec0;
}

/* Resource list */
.resource-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}

.resource-item {
    padding: 22px;
    background: #fff;
    border-radius: 10px;
    border: 1px solid #eef0f3;
}

.resource-item h4 {
    font-size: 16px;
    color: #1a202c;
    margin-bottom: 8px;
}

.resource-item p {
    color: #4a5568;
    font-size: 14px;
}

/* About */
.about-inner {
    max-width: 720px;
    margin: 0 auto;
    text-align: center;
}

.about-inner p {
    color: #4a5568;
    margin-bottom: 14px;
}

/* Footer */
.site-footer {
    padding: 28px 0;
    background: #1a202c;
    color: #cbd5e0;
    font-size: 14px;
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.site-footer a {
    color: #cbd5e0;
    transition: color 0.2s;
}

.site-footer a:hover {
    color: #fff;
}

/* Responsive */
@media (max-width: 640px) {
    .hero {
        padding: 64px 0 48px;
    }

    .hero h1 {
        font-size: 32px;
    }

    .nav a {
        margin-left: 16px;
        font-size: 14px;
    }

    .section {
        padding: 56px 0;
    }

    .section-title {
        font-size: 24px;
    }

    .footer-inner {
        flex-direction: column;
        text-align: center;
    }
}