.video-center{background:#f4f7f5;color:#17362a}
.video-shell{width:min(1320px,calc(100% - 96px));margin:0 auto}
.video-intro{padding:58px 0 0;background:linear-gradient(180deg,#eef4f1 0,#f4f7f5 100%)}
.video-breadcrumb{display:flex;gap:10px;align-items:center;color:#87968f;font-size:13px}
.video-breadcrumb a{color:#587168;text-decoration:none}
.video-breadcrumb a:hover{color:#107553}
.video-breadcrumb strong{color:#17362a;font-weight:600}
.video-intro-row{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(280px,.65fr);gap:80px;align-items:end;padding:64px 0 50px}
.video-eyebrow{margin:0 0 18px;color:#16845d;font-size:12px;font-weight:700;letter-spacing:.19em}
.video-intro h2{margin:0;font-size:clamp(40px,4.7vw,68px);font-weight:500;letter-spacing:-.055em;line-height:1.08}
.video-intro-copy{margin:0 0 7px;color:#667b72;font-size:16px;line-height:1.9}
.video-filters{display:flex;gap:10px;overflow:auto;padding:0 0 28px;scrollbar-width:none}
.video-filters::-webkit-scrollbar{display:none}
.video-filters button{flex:none;padding:10px 18px;border:1px solid #cddbd4;border-radius:999px;background:rgba(255,255,255,.72);color:#526c61;font:600 13px/1.2 Inter,"PingFang SC",sans-serif;cursor:pointer;transition:background .22s,border-color .22s,color .22s}
.video-filters button:hover,.video-filters button:focus-visible{border-color:#16845d;color:#0f7552;outline:0}
.video-filters button.is-active{border-color:#116f50;background:#116f50;color:#fff}
.video-library{padding:68px 0 120px;background:#fff}
.video-library-head{display:flex;align-items:end;justify-content:space-between;margin-bottom:30px}
.video-library-head h2{margin:0;font-size:30px;font-weight:500;letter-spacing:-.03em}
.video-library-head p{margin:0;color:#7b8d85;font-size:13px}
.video-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:34px 22px}
.video-card{overflow:hidden;border:1px solid #dde7e2;border-radius:18px;background:#fff;box-shadow:0 14px 36px rgba(23,74,54,.055);transition:transform .3s ease,box-shadow .3s ease,border-color .3s ease}
.video-card-featured{grid-column:span 2}
.video-card:hover{transform:translateY(-5px);border-color:#b9d9cb;box-shadow:0 23px 48px rgba(23,74,54,.105)}
.video-poster{position:relative;aspect-ratio:16/9;overflow:hidden;background:#dce7e1}
.video-poster::after{position:absolute;inset:0;content:"";background:linear-gradient(180deg,transparent 54%,rgba(5,31,22,.58) 100%);pointer-events:none}
.video-poster img{width:100%;height:100%;object-fit:cover;transition:transform .5s cubic-bezier(.2,.8,.2,1)}
.video-card:hover .video-poster img{transform:scale(1.035)}
.video-play{position:absolute;z-index:2;left:24px;bottom:20px;width:46px;height:46px;border:1px solid rgba(255,255,255,.65);border-radius:50%;background:rgba(255,255,255,.94);box-shadow:0 8px 22px rgba(0,0,0,.14)}
.video-play::after{position:absolute;top:50%;left:52%;width:0;height:0;content:"";border-top:6px solid transparent;border-bottom:6px solid transparent;border-left:9px solid #176f52;transform:translate(-38%,-50%)}
.video-duration{position:absolute;z-index:2;right:17px;bottom:17px;padding:7px 11px;border:1px solid rgba(255,255,255,.28);border-radius:999px;background:rgba(8,43,31,.72);color:#fff;font-size:11px;font-weight:600;letter-spacing:.04em;backdrop-filter:blur(8px)}
.video-card-body{padding:22px 23px 25px}
.video-card-body>p{display:flex;align-items:center;justify-content:space-between;margin:0 0 15px;color:#799087;font-size:11px}
.video-card-body>p span{color:#14815a;font-weight:700;letter-spacing:.06em}
.video-card-body h3{margin:0 0 11px;color:#18382c;font-size:20px;font-weight:600;line-height:1.45;letter-spacing:-.025em}
.video-card-featured .video-card-body h3{font-size:25px}
.video-card-body small{display:block;color:#74867e;font-size:13px;line-height:1.72}
.video-card[hidden]{display:none}
.video-empty{padding:82px 20px;border:1px dashed #cddbd4;border-radius:18px;color:#82938b;text-align:center}
.video-empty[hidden]{display:none}
@media(max-width:900px){.video-shell{width:calc(100% - 40px)}.video-intro-row{grid-template-columns:1fr;gap:28px;padding:48px 0 40px}.video-intro-copy{max-width:650px}.video-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.video-card-featured{grid-column:span 2}}
@media(max-width:620px){.video-intro{padding-top:38px}.video-intro h2{font-size:38px}.video-library{padding:50px 0 82px}.video-grid{grid-template-columns:1fr;gap:20px}.video-card-featured{grid-column:auto}.video-card-featured .video-card-body h3{font-size:20px}.video-library-head h2{font-size:26px}.video-play{left:18px;bottom:16px;width:42px;height:42px}.video-duration{right:14px;bottom:14px}.video-card-body{padding:20px}}
@media(prefers-reduced-motion:reduce){.video-filters button,.video-card,.video-poster img{transition:none}.video-card:hover{transform:none}.video-card:hover .video-poster img{transform:none}}

/* 单节主课程：左封面右文案；标题按语义换行，封面不再压暗。 */
.video-card-featured{grid-column:1 / -1;display:grid;grid-template-columns:minmax(0,1.45fr) minmax(340px,.9fr);align-items:stretch}
.video-card-featured .video-poster{min-height:420px;aspect-ratio:auto}
.video-card-featured .video-poster::after{background:linear-gradient(180deg,transparent 72%,rgba(5,31,22,.22) 100%)}
.video-card-featured .video-card-body{display:flex;flex-direction:column;justify-content:center;padding:clamp(28px,3.6vw,52px) clamp(28px,3.4vw,48px)}
.video-card-featured .video-card-body>p{margin-bottom:16px;font-size:12px}
.video-card-featured .video-card-body h3{margin-bottom:16px;font-size:clamp(22px,1.85vw,28px);line-height:1.4;letter-spacing:-.02em;word-break:keep-all}
.video-card-featured .video-card-body small{max-width:36ch;font-size:14px;line-height:1.8}
@media(max-width:900px){.video-card-featured{grid-column:1 / -1;grid-template-columns:1fr}.video-card-featured .video-poster{min-height:0;aspect-ratio:16/9}}
@media(max-width:620px){.video-card-featured{grid-column:auto}.video-card-featured .video-card-body{padding:26px 22px}.video-card-featured .video-card-body h3{font-size:22px}.video-card-featured .video-card-body small{font-size:14px}}