/* 小黑源码社区 - 前端样式（浅色/白色主题） */
:root {
    --kb-bg: #f4f6fa;
    --kb-bg-soft: #ffffff;
    --kb-card: #ffffff;
    --kb-card-2: #f2f4f8;
    --kb-border: #e4e8f0;
    --kb-border-strong: #d3dae7;
    --kb-text: #1b2333;
    --kb-text-soft: #4b5565;
    --kb-muted: #7b8494;
    --kb-primary: #ff6a00;
    --kb-primary-2: #ff2d55;
    --kb-cyan: #0891b2;
    --kb-green: #16a34a;
    --kb-radius: 14px;
    --kb-shadow: 0 6px 20px rgba(15, 23, 42, .06);
    --kb-shadow-hover: 0 14px 32px rgba(15, 23, 42, .12);
}

* { box-sizing: border-box; }

body {
    margin: 0;
    background: var(--kb-bg);
    color: var(--kb-text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    font-size: 14px;
    line-height: 1.7;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { margin: 0; padding: 0; list-style: none; }

.kb-container { width: 1200px; max-width: 94%; margin: 0 auto; }

/* ============ 顶部导航 ============ */
.kb-header {
    position: sticky; top: 0; z-index: 100;
    background: rgba(255, 255, 255, .94);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--kb-border);
    box-shadow: 0 2px 12px rgba(15, 23, 42, .04);
}
.kb-header .kb-container { display: flex; align-items: center; gap: 24px; height: 64px; }
.kb-logo { display: flex; align-items: center; gap: 10px; font-size: 19px; font-weight: 700; letter-spacing: .5px; }
.kb-logo i {
    width: 32px; height: 32px; border-radius: 9px;
    background: linear-gradient(135deg, var(--kb-primary), var(--kb-primary-2));
    display: inline-flex; align-items: center; justify-content: center;
    font-style: normal; font-size: 16px; color: #fff;
}
.kb-logo b { background: linear-gradient(135deg, #ff6a00, #ff2d55); -webkit-background-clip: text; color: transparent; }
.kb-nav { display: flex; gap: 4px; }
.kb-nav a { padding: 8px 14px; border-radius: 8px; color: var(--kb-text-soft); font-size: 14px; }
.kb-nav a:hover { color: var(--kb-primary); background: var(--kb-card-2); }
.kb-nav a.active { color: var(--kb-primary); background: #fff2e8; font-weight: 600; }

.kb-search { flex: 1; max-width: 380px; position: relative; }
.kb-search input {
    width: 100%; height: 38px; padding: 0 42px 0 14px;
    background: #fff; border: 1px solid var(--kb-border-strong);
    border-radius: 20px; color: var(--kb-text); outline: none; font-size: 13px;
}
.kb-search input:focus { border-color: var(--kb-primary); box-shadow: 0 0 0 3px rgba(255, 106, 0, .12); }
.kb-search button {
    position: absolute; right: 4px; top: 4px; height: 30px; width: 34px;
    border: 0; border-radius: 16px; cursor: pointer;
    background: linear-gradient(135deg, var(--kb-primary), var(--kb-primary-2)); color: #fff;
}

.kb-user { display: flex; align-items: center; gap: 12px; }
.kb-user .kb-avatar { width: 32px; height: 32px; border-radius: 50%; object-fit: cover; background: var(--kb-card-2); }
.kb-user .kb-balance { font-size: 12px; color: var(--kb-cyan); font-weight: 600; }
.kb-user-menu { position: relative; }
.kb-user-menu:hover .kb-dropdown { display: block; }
.kb-dropdown {
    display: none; position: absolute; right: 0; top: 42px; width: 150px;
    background: #fff; border: 1px solid var(--kb-border); border-radius: 10px; overflow: hidden;
    box-shadow: var(--kb-shadow-hover);
}
.kb-dropdown a { display: block; padding: 10px 14px; font-size: 13px; color: var(--kb-text-soft); }
.kb-dropdown a:hover { background: var(--kb-card-2); color: var(--kb-primary); }

/* ============ 按钮 ============ */
.kb-btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 6px;
    height: 38px; padding: 0 20px; border: 0; border-radius: 10px;
    background: var(--kb-card-2); color: var(--kb-text); cursor: pointer; font-size: 14px;
    transition: .2s;
}
.kb-btn:hover { opacity: .9; }
.kb-btn-primary { background: linear-gradient(135deg, var(--kb-primary), var(--kb-primary-2)); color: #fff; font-weight: 600; }
.kb-btn-cyan { background: linear-gradient(135deg, #0ea5b7, var(--kb-cyan)); color: #fff; font-weight: 600; }
.kb-btn-ghost { background: #fff; border: 1px solid var(--kb-border-strong); color: var(--kb-text-soft); }
.kb-btn-ghost:hover { border-color: var(--kb-primary); color: var(--kb-primary); }
.kb-btn-block { width: 100%; }
.kb-btn-lg { height: 46px; font-size: 15px; }

/* ============ Hero ============ */
.kb-hero {
    padding: 64px 0 48px;
    background: linear-gradient(180deg, #ffffff 0%, #f6f8fc 100%);
    border-bottom: 1px solid var(--kb-border);
}
.kb-hero h1 { margin: 0 0 14px; font-size: 38px; line-height: 1.3; color: #101828; }
.kb-hero h1 span { background: linear-gradient(135deg, var(--kb-primary), #ff9a3c); -webkit-background-clip: text; color: transparent; }
.kb-hero p { margin: 0 0 26px; color: var(--kb-text-soft); font-size: 15px; }
.kb-hero-form { display: flex; gap: 10px; max-width: 560px; }
.kb-hero-form input {
    flex: 1; height: 46px; padding: 0 18px; border-radius: 12px;
    background: #fff; border: 1px solid var(--kb-border-strong); color: var(--kb-text); outline: none;
}
.kb-hero-form input:focus { border-color: var(--kb-primary); box-shadow: 0 0 0 3px rgba(255, 106, 0, .12); }
.kb-stats { display: flex; gap: 40px; margin-top: 34px; }
.kb-stats div b { display: block; font-size: 24px; color: #101828; }
.kb-stats div span { font-size: 12px; color: var(--kb-muted); }

/* ============ 区块标题 ============ */
.kb-section { padding: 40px 0; }
.kb-section-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 20px; }
.kb-section-head h2 { margin: 0; font-size: 21px; color: #101828; }
.kb-section-head h2::before { content: ''; display: inline-block; width: 4px; height: 18px; margin-right: 10px; border-radius: 2px; background: linear-gradient(var(--kb-primary), var(--kb-primary-2)); vertical-align: -2px; }
.kb-section-head a { color: var(--kb-muted); font-size: 13px; }
.kb-section-head a:hover { color: var(--kb-primary); }

/* ============ 分类快捷 ============ */
.kb-cates { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 12px; }
.kb-cate-item {
    display: flex; align-items: center; gap: 10px; padding: 14px 16px;
    background: #fff; border: 1px solid var(--kb-border); border-radius: 12px; transition: .2s;
}
.kb-cate-item:hover { border-color: var(--kb-primary); color: var(--kb-primary); transform: translateY(-2px); box-shadow: var(--kb-shadow); }
.kb-cate-item img { width: 26px; height: 26px; object-fit: contain; }
.kb-cate-item b { font-size: 14px; font-weight: 600; }
.kb-cate-item span { margin-left: auto; font-size: 12px; color: var(--kb-muted); }

/* ============ 商品卡片 ============ */
.kb-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(268px, 1fr)); gap: 18px; }
.kb-card {
    background: #fff; border: 1px solid var(--kb-border);
    border-radius: var(--kb-radius); overflow: hidden; transition: .25s;
}
.kb-card:hover { transform: translateY(-4px); border-color: var(--kb-border-strong); box-shadow: var(--kb-shadow-hover); }
.kb-card-cover { position: relative; padding-top: 56%; background: var(--kb-card-2) center/cover no-repeat; }
.kb-card-cover .kb-badge {
    position: absolute; left: 10px; top: 10px; padding: 3px 9px; border-radius: 6px;
    font-size: 11px; color: #fff; background: rgba(17, 24, 39, .72); backdrop-filter: blur(4px);
}
.kb-card-cover .kb-badge.free { background: var(--kb-green); }
.kb-card-cover .kb-badge.hot { background: linear-gradient(135deg, var(--kb-primary), var(--kb-primary-2)); }
.kb-card-body { padding: 14px 16px 16px; }
.kb-card-body h3 { margin: 0 0 8px; font-size: 15px; font-weight: 600; line-height: 1.5; height: 44px; overflow: hidden; color: #101828; }
.kb-card-body p { margin: 0 0 12px; color: var(--kb-muted); font-size: 12px; height: 34px; overflow: hidden; }
.kb-card-foot { display: flex; align-items: center; justify-content: space-between; }
.kb-price { color: var(--kb-primary); font-size: 18px; font-weight: 700; }
.kb-price.free { color: var(--kb-green); }
.kb-price del { margin-left: 6px; color: var(--kb-muted); font-size: 12px; font-weight: 400; }
.kb-meta { display: flex; gap: 12px; color: var(--kb-muted); font-size: 12px; }

.kb-tag { display: inline-block; padding: 2px 8px; margin: 0 6px 6px 0; border-radius: 6px; background: var(--kb-card-2); color: var(--kb-text-soft); font-size: 12px; }

/* ============ 列表页 ============ */
.kb-layout { display: grid; grid-template-columns: 220px 1fr; gap: 24px; padding: 28px 0 60px; }
.kb-side { background: #fff; border: 1px solid var(--kb-border); border-radius: var(--kb-radius); padding: 14px; align-self: start; }
.kb-side h4 { margin: 0 0 10px; font-size: 14px; color: var(--kb-muted); font-weight: 500; }
.kb-side a { display: block; padding: 9px 12px; border-radius: 8px; font-size: 14px; color: var(--kb-text-soft); }
.kb-side a:hover { background: var(--kb-card-2); color: var(--kb-primary); }
.kb-side a.active { background: #fff2e8; color: var(--kb-primary); font-weight: 600; }
.kb-filters { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 18px; }
.kb-filters a { padding: 6px 14px; border-radius: 20px; background: #fff; border: 1px solid var(--kb-border-strong); font-size: 13px; color: var(--kb-text-soft); }
.kb-filters a:hover { border-color: var(--kb-primary); color: var(--kb-primary); }
.kb-filters a.active { background: linear-gradient(135deg, var(--kb-primary), var(--kb-primary-2)); color: #fff; border-color: transparent; }

/* ============ 详情 ============ */
.kb-detail { display: grid; grid-template-columns: 1fr 320px; gap: 24px; padding: 28px 0 60px; }
.kb-panel { background: #fff; border: 1px solid var(--kb-border); border-radius: var(--kb-radius); padding: 20px; }
.kb-detail-cover { border-radius: var(--kb-radius); overflow: hidden; border: 1px solid var(--kb-border); background: #f7f9fc; }
.kb-detail-cover img { width: 100%; }
.kb-detail h1 { margin: 18px 0 10px; font-size: 24px; color: #101828; }
.kb-detail .kb-sub { color: var(--kb-muted); margin-bottom: 16px; }
.kb-content { margin-top: 22px; color: var(--kb-text-soft); font-size: 14px; }
.kb-content img { max-width: 100%; border-radius: 10px; }
.kb-content pre { background: #f7f9fc; padding: 14px; border-radius: 10px; overflow-x: auto; border: 1px solid var(--kb-border); color: #1b2333; }
.kb-gallery { display: flex; gap: 10px; margin-top: 12px; flex-wrap: wrap; }
.kb-gallery img { width: 108px; height: 68px; object-fit: cover; border-radius: 8px; border: 1px solid var(--kb-border); cursor: pointer; }

.kb-buy-box .kb-price-big { font-size: 32px; color: var(--kb-primary); font-weight: 800; }
.kb-buy-box .kb-price-big.free { color: var(--kb-green); }
.kb-buy-box ul { margin: 16px 0; }
.kb-buy-box ul li { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px dashed var(--kb-border); font-size: 13px; color: var(--kb-muted); }
.kb-buy-box ul li b { color: var(--kb-text); font-weight: 500; }

/* ============ 表单 ============ */
.kb-form-box { width: 420px; max-width: 92%; margin: 60px auto; background: #fff; border: 1px solid var(--kb-border); border-radius: var(--kb-radius); padding: 32px; box-shadow: var(--kb-shadow); }
.kb-form-box h2 { margin: 0 0 6px; font-size: 22px; color: #101828; }
.kb-form-box .kb-tip { color: var(--kb-muted); font-size: 13px; margin-bottom: 22px; }
.kb-field { margin-bottom: 16px; }
.kb-field label { display: block; margin-bottom: 6px; font-size: 13px; color: var(--kb-text-soft); }
.kb-field input, .kb-field select, .kb-field textarea {
    width: 100%; height: 42px; padding: 0 14px; border-radius: 10px;
    background: #fff; border: 1px solid var(--kb-border-strong); color: var(--kb-text); outline: none; font-size: 14px;
}
.kb-field textarea { height: auto; padding: 12px 14px; }
.kb-field input:focus, .kb-field select:focus, .kb-field textarea:focus { border-color: var(--kb-primary); box-shadow: 0 0 0 3px rgba(255, 106, 0, .12); }
.kb-alert { padding: 10px 14px; border-radius: 10px; margin-bottom: 16px; font-size: 13px; }
.kb-alert.error { background: #fef2f2; color: #b91c1c; border: 1px solid #fecaca; }
.kb-alert.success { background: #f0fdf4; color: #15803d; border: 1px solid #bbf7d0; }
.kb-form-foot { margin-top: 18px; text-align: center; color: var(--kb-muted); font-size: 13px; }
.kb-form-foot a { color: var(--kb-primary); }

/* ============ 会员中心 ============ */
.kb-user-layout { display: grid; grid-template-columns: 210px 1fr; gap: 24px; padding: 28px 0 60px; }
.kb-user-card { text-align: center; padding: 24px 16px; }
.kb-user-card img { width: 68px; height: 68px; border-radius: 50%; margin: 0 auto 10px; object-fit: cover; background: var(--kb-card-2); }
.kb-user-card b { display: block; font-size: 15px; color: #101828; }
.kb-user-card .kb-money { margin-top: 8px; color: var(--kb-cyan); font-size: 13px; font-weight: 600; }
.kb-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.kb-table th, .kb-table td { padding: 12px 10px; text-align: left; border-bottom: 1px solid var(--kb-border); }
.kb-table th { color: var(--kb-muted); font-weight: 500; }
.kb-table td a { color: var(--kb-cyan); }
.kb-empty { padding: 60px 0; text-align: center; color: var(--kb-muted); }

/* ============ 分页 ============ */
.kb-pager { display: flex; gap: 8px; justify-content: center; margin-top: 28px; flex-wrap: wrap; }
.kb-pager a, .kb-pager span {
    min-width: 36px; height: 36px; padding: 0 12px; border-radius: 9px;
    display: inline-flex; align-items: center; justify-content: center;
    background: #fff; border: 1px solid var(--kb-border-strong); font-size: 13px; color: var(--kb-text-soft);
}
.kb-pager a:hover { border-color: var(--kb-primary); color: var(--kb-primary); }
.kb-pager .active { background: linear-gradient(135deg, var(--kb-primary), var(--kb-primary-2)); color: #fff; border-color: transparent; }

/* ============ 页脚 ============ */
.kb-footer { border-top: 1px solid var(--kb-border); padding: 30px 0; margin-top: 40px; color: var(--kb-muted); font-size: 13px; background: #fff; }
.kb-footer .kb-container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
.kb-footer a { color: var(--kb-muted); margin-left: 14px; }
.kb-footer a:hover { color: var(--kb-primary); }

@media (max-width: 900px) {
    .kb-layout, .kb-detail, .kb-user-layout { grid-template-columns: 1fr; }
    .kb-header .kb-container { flex-wrap: wrap; height: auto; padding: 12px 0; gap: 12px; }
    .kb-nav { order: 3; width: 100%; overflow-x: auto; }
    .kb-search { order: 2; }
    .kb-hero h1 { font-size: 27px; }
}