:root {
    --cb-bg: #162a22;
    --cb-surface: #1d332a;
    --cb-border: rgba(255, 255, 255, 0.25);
    --cb-chalk-white: #f3f4f6;
    --cb-chalk-yellow: #fef08a;
    --cb-chalk-pink: #fbcfe8;
    --cb-chalk-blue: #a5f3fc;
    --cb-price: #fbcfe8;
    --cb-radius: 6px;
}
body { margin: 0; background-color: var(--cb-bg); color: var(--cb-chalk-white); font-family: "PingFang SC", "Microsoft YaHei", sans-serif; -webkit-font-smoothing: antialiased; }
.cb-header { background-color: #11201a; border-bottom: 2px dashed var(--cb-border); padding: 18px 0; }
.cb-nav-inner { max-width: 1400px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; padding: 0 24px; box-sizing: border-box; }
.cb-logo img { height: 26px; filter: grayscale(1) invert(1) brightness(1.2); }
.cb-menu { display: flex; gap: 35px; }
.cb-menu a { text-decoration: none; color: var(--cb-border); font-weight: 700; font-size: 14px; transition: 0.3s; }
.cb-menu a:hover { color: var(--cb-chalk-yellow); text-shadow: 0 0 5px var(--cb-chalk-yellow); }
.cb-container { max-width: 1400px; margin: 40px auto; padding: 0 24px; box-sizing: border-box; }
.cb-notice { background: var(--cb-surface); border-radius: var(--cb-radius); border: 2px dashed var(--cb-border); padding: 18px 24px; font-size: 13px; color: var(--cb-chalk-white); line-height: 1.6; display: flex; align-items: center; gap: 12px; position: relative; }
.cb-notice::before { content: "[课堂公告]"; position: absolute; top: -10px; left: 15px; background: var(--cb-bg); color: var(--cb-chalk-yellow); font-size: 10px; padding: 1px 6px; font-weight: bold; border: 1px solid var(--cb-border); }
.cb-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 16px; }
.cb-card { background-color: var(--cb-surface); border: 1px solid var(--cb-border); border-radius: var(--cb-radius); padding: 16px; text-decoration: none; transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1); display: flex; flex-direction: column; position: relative; overflow: hidden; }
.cb-card:hover { transform: translateY(-4px); border-color: var(--cb-chalk-yellow); box-shadow: 0 0 15px rgba(254, 240, 138, 0.2); }
.cb-img-box { width: 100%; aspect-ratio: 1; background: #11201a; border-radius: 4px; display: flex; align-items: center; justify-content: center; margin-bottom: 12px; border: 1px dashed var(--cb-border); }
.cb-img-box img { width: 60%; height: 60%; object-fit: contain; opacity: 0.85; transition: 0.3s; }
.cb-card:hover .cb-img-box img { opacity: 1; transform: scale(1.04); }
.cb-name { font-size: 13px; font-weight: 700; color: var(--cb-chalk-white); height: 38px; line-height: 1.4; overflow: hidden; margin-bottom: 12px; }
.cb-meta { display: flex; justify-content: space-between; align-items: center; margin-top: auto; border-top: 1px dashed var(--cb-border); padding-top: 10px; }
.cb-price { color: var(--cb-price); font-weight: 800; font-size: 16px; text-shadow: 0 0 4px rgba(251, 207, 232, 0.3); }
.cb-sell { font-size: 11px; color: var(--cb-border); }
.cb-tag { position: absolute; top: 12px; left: 12px; background: rgba(254, 240, 138, 0.1); color: var(--cb-chalk-yellow); font-size: 10px; padding: 2px 6px; border-radius: 4px; font-weight: bold; border: 1px solid var(--cb-chalk-yellow); }
.cb-detail-grid { display: grid; grid-template-columns: 1.3fr 1fr; gap: 32px; }
.cb-box { background: var(--cb-surface); border-radius: var(--cb-radius); padding: 35px; border: 1px solid var(--cb-border); }
.cb-h1 { font-size: 24px; font-weight: 800; margin: 0 0 20px 0; color: var(--cb-chalk-white); border-bottom: 1px dashed var(--cb-border); padding-bottom: 12px; }
.cb-input { width: 100%; height: 46px; background: #11201a; border: 1px solid var(--cb-border); border-radius: 4px; padding: 0 15px; font-size: 14px; box-sizing: border-box; outline: none; transition: 0.3s; margin-top: 8px; color: var(--cb-chalk-white); }
.cb-input:focus { border-color: var(--cb-chalk-yellow); background: var(--cb-surface); }
.cb-label { display: block; font-size: 12px; font-weight: 700; color: var(--cb-border); }
.cb-btn { width: 100%; height: 50px; background: var(--cb-bg); color: var(--cb-chalk-white); border: 1px solid var(--cb-border); border-radius: 4px; font-size: 15px; font-weight: 700; cursor: pointer; transition: 0.3s; margin-top: 20px; }
.cb-btn:hover { background: var(--cb-chalk-yellow); color: #000; text-shadow: none; box-shadow: 0 0 15px var(--cb-chalk-yellow); }
.cb-footer { background: #11201a; border-top: 2px dashed var(--cb-border); padding: 50px 0; margin-top: 80px; text-align: center; }
@media (max-width: 1400px) { .cb-grid { grid-template-columns: repeat(5, 1fr); } }
@media (max-width: 1000px) { .cb-grid { grid-template-columns: repeat(3, 1fr); } .cb-detail-grid { grid-template-columns: 1fr; } }
@media (max-width: 600px) { .cb-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; } }