/* 视频区样式（2026-09-29 新增）
   规矩：① class 一律 vd- 前缀（不碰 base.css / style.css）
        ② 只在 /learn 页用；配色跟认知篇一致（深青主色 + 中性灰）
        ③ 手机端竖屏一列（视频卡片横排会挤成一团） */

.vd-section { margin-top: 30px; padding-top: 22px; border-top: 1px solid #e6ecf1; }
.vd-head { display: flex; align-items: flex-end; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.vd-h2 { font-size: 17px; font-weight: 800; color: #123c52; margin: 0; }
.vd-p { font-size: 13px; color: #6b7688; margin: 0; }
.vd-badge { font-size: 11.5px; font-weight: 700; color: #8a5a00; background: #fff4d6;
    border: 1px solid #f4d98a; border-radius: 999px; padding: 2px 8px; }

.vd-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.vd-card { border: 1px solid #e3eaf1; border-radius: 12px; overflow: hidden; background: #fff;
    cursor: pointer; transition: box-shadow .18s, transform .18s; display: flex; flex-direction: column; }
.vd-card:hover { box-shadow: 0 8px 22px rgba(15, 58, 82, .10); transform: translateY(-1px); }
.vd-thumb { position: relative; aspect-ratio: 16/9; background: linear-gradient(135deg, #0f3a52, #1b6b8f);
    display: flex; align-items: center; justify-content: center; overflow: hidden; }
.vd-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.vd-ph { font-size: 26px; opacity: .5; }
.vd-dur { position: absolute; right: 8px; bottom: 8px; background: rgba(0,0,0,.62); color: #fff;
    font-size: 11.5px; padding: 1px 6px; border-radius: 4px; }
.vd-tag-free, .vd-tag-lock { position: absolute; left: 8px; top: 8px; font-size: 11.5px; font-weight: 700;
    padding: 2px 7px; border-radius: 999px; }
.vd-tag-free { background: #e6f7ee; color: #12734a; border: 1px solid #a8e0c3; }
.vd-tag-lock { background: rgba(15,30,45,.66); color: #fff; }
.vd-play { position: absolute; inset: 0; margin: auto; width: 46px; height: 46px; border-radius: 50%;
    background: rgba(255,255,255,.86); color: #0f3a52; display: flex; align-items: center;
    justify-content: center; font-size: 17px; padding-left: 3px; opacity: .92; }
.vd-locked .vd-play { background: rgba(255,255,255,.62); }
.vd-body { padding: 10px 12px 12px; flex: 1; display: flex; flex-direction: column; }
.vd-title { font-size: 14px; font-weight: 700; color: #1f2937; line-height: 1.45; margin-bottom: 4px; }
.vd-sum { font-size: 12.5px; color: #6b7688; line-height: 1.6; flex: 1; }
.vd-meta { font-size: 12px; color: #93a6b4; margin-top: 8px; }
.vd-empty { border: 1px dashed #d5e0ea; border-radius: 12px; padding: 26px; text-align: center;
    color: #6b7688; font-size: 13.5px; background: #fafcfe; }

/* ── 播放器 + 留言弹层 ── */
.vd-modal { position: fixed; inset: 0; z-index: 9000; background: rgba(10,22,34,.55);
    display: flex; align-items: center; justify-content: center; padding: 18px; }
.vd-modal[hidden] { display: none; }
.vd-box { background: #fff; border-radius: 14px; width: 100%; max-width: 880px; max-height: 92vh;
    display: flex; flex-direction: column; overflow: hidden; box-shadow: 0 18px 60px rgba(0,0,0,.28); }
.vd-box-head { display: flex; align-items: flex-start; gap: 10px; padding: 14px 16px 10px; border-bottom: 1px solid #eef3f7; }
.vd-box-title { font-size: 15.5px; font-weight: 800; color: #123c52; flex: 1; line-height: 1.5; }
.vd-close { border: 1px solid #e3eaf1; background: #fff; color: #5b6b7f; border-radius: 8px;
    padding: 5px 11px; font-size: 13px; cursor: pointer; font-family: inherit; }
.vd-close:hover { background: #f4f8fb; }
.vd-stage { background: #0b1b26; position: relative; aspect-ratio: 16/9; width: 100%; }
.vd-stage video, .vd-stage iframe { width: 100%; height: 100%; border: 0; display: block; background: #000; }
.vd-loading { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
    color: #cfe0ea; font-size: 13.5px; }
.vd-tip { padding: 26px 20px; text-align: center; color: #5b6b7f; font-size: 13.5px; line-height: 1.8; }
.vd-tip a.btn, .vd-tip button { display: inline-block; margin-top: 12px; padding: 9px 18px; border: 0; border-radius: 9px;
    background: #1b6b8f; color: #fff; font-size: 13.5px; font-weight: 700; text-decoration: none;
    cursor: pointer; font-family: inherit; }
.vd-desc { padding: 12px 16px 4px; font-size: 13px; color: #5b6b7f; line-height: 1.7; }
.vd-acts { padding: 6px 16px 12px; display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.vd-link { font-size: 12.5px; color: #1d6fe0; text-decoration: none; }
.vd-link:hover { text-decoration: underline; }
.vd-cmts { border-top: 1px solid #eef3f7; padding: 12px 16px 16px; overflow: auto; }
.vd-cmts h4 { font-size: 13.5px; color: #123c52; margin: 0 0 10px; }
.vd-cmt { padding: 9px 0; border-bottom: 1px dashed #eef3f7; }
.vd-cmt:last-child { border-bottom: 0; }
.vd-cmt-top { display: flex; gap: 8px; align-items: baseline; }
.vd-cmt-user { font-size: 12.5px; font-weight: 700; color: #33404f; }
.vd-cmt-time { font-size: 11.5px; color: #9fb0bd; }
.vd-cmt-body { font-size: 13px; color: #33404f; line-height: 1.7; margin-top: 3px; word-break: break-word; }
.vd-cmt-reply { margin-top: 6px; background: #f5fafd; border-left: 3px solid #7fc4e0;
    padding: 7px 10px; font-size: 12.5px; color: #2b4a5c; border-radius: 0 8px 8px 0; line-height: 1.7; }
.vd-cmt-empty { color: #93a6b4; font-size: 12.5px; padding: 6px 0 2px; }
.vd-cmt-form { display: flex; gap: 8px; margin-top: 10px; }
.vd-cmt-form input { flex: 1; border: 1px solid #e3eaf1; border-radius: 9px; padding: 9px 11px;
    font-size: 13px; font-family: inherit; color: #1f2937; }
.vd-cmt-form button { border: 0; border-radius: 9px; background: #1b6b8f; color: #fff;
    padding: 0 16px; font-size: 13px; font-weight: 700; cursor: pointer; font-family: inherit; }
.vd-cmt-form button:disabled { opacity: .55; cursor: default; }

@media (max-width: 980px) { .vd-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) {
    .vd-grid { grid-template-columns: 1fr; }
    .vd-modal { padding: 0; }
    .vd-box { max-width: none; height: 100%; max-height: none; border-radius: 0; }
    .vd-cmt-form button { padding: 0 12px; }
}