/* 安小助 · 3D课堂（第29应用）
   视觉：晴空蓝渐变 hero（tone classroom3d）+ 说明横幅 + 沉浸式全屏播放器。
   全屏播放器层 z-index 高于 tabbar/topbar，返回按钮回到课程列表。 */

.tool-hero.is-classroom3d { background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 55%, #0369a1 100%); }
.tool-hero.is-classroom3d .tool-hero-ico { color: #bae6fd; }

.c3d-page { padding-bottom: calc(var(--tabbar-h, 56px) + var(--safe-b, 0px) + 18px); }

/* 顶部说明横幅 */
.c3d-banner { display: flex; align-items: flex-start; gap: 10px; margin: 14px 16px 4px; padding: 12px 14px; border-radius: 12px; background: #e0f2fe; border: 1px solid #bae6fd; color: #075985; }
.c3d-banner-ico { width: 18px; height: 18px; flex: 0 0 auto; margin-top: 2px; color: #0284c7; }
.c3d-banner-ico svg { width: 18px; height: 18px; }
.c3d-banner p { margin: 0; font-size: 13px; line-height: 1.7; }
.c3d-banner b { color: #0c4a6e; }

/* 课程列表 */
.c3d-feed { display: flex; flex-direction: column; gap: 10px; padding: 12px 16px 8px; }

.c3d-card { display: flex; align-items: center; gap: 12px; width: 100%; text-align: left; padding: 14px; border-radius: 14px; background: #fff; border: 1px solid #e2e8f0; box-shadow: 0 1px 2px rgba(15, 23, 42, .04); cursor: pointer; transition: transform .15s ease, box-shadow .18s ease, border-color .18s ease; }
.c3d-card:hover { border-color: #7dd3fc; box-shadow: 0 4px 14px rgba(14, 165, 233, .14); transform: translateY(-1px); }
.c3d-card:active { transform: translateY(0); }

.c3d-card-ico { flex: 0 0 auto; width: 48px; height: 48px; border-radius: 13px; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, #e0f2fe, #bae6fd); color: #0284c7; }
.c3d-card-ico svg { width: 24px; height: 24px; }

.c3d-card-main { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 3px; }
.c3d-card-title { font-size: 15px; font-weight: 600; color: #0f172a; line-height: 1.45; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.c3d-card-note { font-size: 12px; color: #64748b; line-height: 1.55; overflow: hidden; text-overflow: ellipsis; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; }
.c3d-card-meta { display: flex; flex-wrap: wrap; gap: 4px 10px; font-size: 11.5px; color: #94a3b8; margin-top: 2px; }
.c3d-card-meta i { font-style: normal; display: inline-flex; align-items: center; gap: 4px; }

.c3d-card-go { flex: 0 0 auto; width: 34px; height: 34px; border-radius: 10px; display: flex; align-items: center; justify-content: center; background: #0ea5e9; color: #fff; }
.c3d-card-go svg { width: 17px; height: 17px; }

/* 空态 / 加载骨架 */
.c3d-empty { text-align: center; padding: 44px 16px; color: #94a3b8; font-size: 13px; }
.c3d-empty p { margin: 0 0 12px; }
.c3d-retry { border: 1px solid #bae6fd; background: #e0f2fe; color: #0369a1; font-size: 13px; padding: 8px 18px; border-radius: 999px; cursor: pointer; }
.c3d-skeleton { display: flex; flex-direction: column; gap: 10px; }
.c3d-skeleton span { display: block; height: 88px; border-radius: 14px; background: linear-gradient(90deg, #f1f5f9 25%, #e2e8f0 37%, #f1f5f9 63%); background-size: 400% 100%; animation: c3d-shimmer 1.3s ease infinite; }
@keyframes c3d-shimmer { 0% { background-position: 100% 0; } 100% { background-position: 0 0; } }

/* 底部署名 */
.c3d-credit { text-align: center; font-size: 12px; color: #94a3b8; padding: 6px 16px 22px; letter-spacing: .3px; }
.c3d-credit b { color: #0284c7; font-weight: 600; }

/* ── 沉浸式播放器（全屏覆盖） ── */
/* #main 默认 z-index:1 会形成层叠上下文，把内部 fixed 播放器压在 tabbar(30) 之下；
   沉浸态解除 #main 的层叠限制并隐藏顶/底栏，确保真正全屏。 */
body.c3d-immersive #main { position: static; z-index: auto; max-width: none; padding: 0; }
body.c3d-immersive #topbar,
body.c3d-immersive .tabbar { display: none !important; }
.c3d-stage { position: fixed; inset: 0; z-index: 1200; display: flex; flex-direction: column; background: #0b1220; }
.c3d-stage-top { flex: 0 0 auto; display: flex; align-items: center; gap: 10px; padding: calc(var(--safe-t, 0px) + 10px) 14px 10px; background: #0f172a; color: #fff; }
.c3d-back { display: inline-flex; align-items: center; gap: 4px; padding: 6px 10px 6px 6px; border: 0; border-radius: 9px; background: rgba(255, 255, 255, .1); color: #e2e8f0; font-size: 13px; cursor: pointer; }
.c3d-back svg { width: 18px; height: 18px; }
.c3d-back:active { background: rgba(255, 255, 255, .18); }
.c3d-stage-title { flex: 1 1 auto; min-width: 0; font-size: 14px; font-weight: 600; color: #f8fafc; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.c3d-stage-tag { flex: 0 0 auto; font-size: 11px; color: #7dd3fc; background: rgba(14, 165, 233, .18); border: 1px solid rgba(125, 211, 252, .35); padding: 3px 9px; border-radius: 999px; }
.c3d-frame-wrap { flex: 1 1 auto; min-height: 0; position: relative; }
.c3d-frame { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; display: block; background: #0b1220; }

/* PC 端：列表限宽居中，双列 */
@media (min-width: 760px) {
  .c3d-banner { max-width: 860px; margin-inline: auto; }
  .c3d-feed { max-width: 860px; margin-inline: auto; display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-items: stretch; }
  .c3d-credit { padding-bottom: 26px; }
}