/* 结构透视 3D · 沉浸式世界版 .s3d-* 前缀 */
/* struct3d 视图:世界用 fixed 全屏覆盖,绕开 main 的 margin-left 叠加问题(侧栏 z-index:100 浮在上) */
.s3d-world{position:fixed;left:0;top:0;right:0;bottom:0;background:#9ec9e8;overflow:hidden;z-index:1}

.s3d-canvas-host{position:absolute;inset:0}
.s3d-canvas-host canvas{display:block;width:100%;height:100%;cursor:grab}
.s3d-canvas-host canvas:active{cursor:grabbing}
.s3d-loading{position:absolute;inset:0;display:grid;place-content:center;color:#2c3e50;font-size:15px;font-weight:600;background:linear-gradient(135deg,#9ec9e8,#b8d8ee)}

/* 顶部 HUD */
.s3d-hud-top{position:absolute;top:0;left:0;right:0;display:flex;align-items:center;justify-content:space-between;gap:14px;padding:12px 18px;background:linear-gradient(180deg,rgba(13,15,21,.7),transparent);pointer-events:none}
.s3d-hud-top>*{pointer-events:auto}
.s3d-back{padding:7px 14px;border-radius:var(--r-s);background:rgba(29,35,48,.9);color:var(--t);font-size:13px;border:1px solid var(--line);backdrop-filter:blur(8px);transition:.2s}
.s3d-back:hover{background:var(--card2)}
.s3d-hud-title{display:flex;flex-direction:column;align-items:center;flex:1}
.s3d-eyebrow{color:var(--gold);font-size:10px;letter-spacing:.18em;font-weight:700}
.s3d-hud-title b{font:700 17px "Songti SC","STSong",serif;color:#fff;text-shadow:0 2px 8px rgba(0,0,0,.4)}
.s3d-hud-hint{font-size:11px;color:rgba(255,255,255,.85);background:rgba(13,15,21,.55);padding:6px 10px;border-radius:var(--r-s);backdrop-filter:blur(8px);max-width:340px}
@media(max-width:768px){.s3d-hud-hint{display:none}.s3d-hud-title b{font-size:14px}}

/* 左侧建筑清单(可折叠) */
.s3d-rail{position:absolute;left:14px;top:64px;width:200px;background:rgba(13,15,21,.85);backdrop-filter:blur(12px);border:1px solid var(--line);border-radius:var(--r);overflow:hidden;z-index:4}
.s3d-rail-toggle{width:100%;padding:10px 14px;text-align:left;font-size:12px;color:var(--t2);font-weight:600;background:var(--card)}
.s3d-rail-toggle:hover{color:var(--t)}
.s3d-rail ul{max-height:0;overflow:hidden;transition:max-height .3s var(--ease);list-style:none;margin:0;padding:0}
.s3d-rail.open ul{max-height:600px;overflow-y:auto}
.s3d-rail-item{display:flex;gap:9px;align-items:center;padding:9px 13px;cursor:pointer;border-left:3px solid var(--accent,var(--gold));transition:.2s}
.s3d-rail-item:hover{background:var(--card2)}
.s3d-rail-dot{width:8px;height:8px;border-radius:50%;flex-shrink:0;box-shadow:0 0 6px currentColor}
.s3d-rail-item b{display:block;font-size:12px;color:var(--t);font-weight:600}
.s3d-rail-item span{font-size:10px;color:var(--t3)}
@media(max-width:768px){
  .s3d-rail{width:170px;top:56px;left:10px}
}

/* 复位按钮 */
.s3d-reset{position:absolute;right:18px;bottom:24px;padding:10px 18px;border-radius:var(--r);background:rgba(240,200,118,.95);color:#1a1a1a;font-size:13px;font-weight:700;box-shadow:var(--shadow-lg);z-index:5;transition:.2s}
.s3d-reset:hover{transform:translateY(-2px)}
.s3d-reset[hidden]{display:none}

/* 就地浮层面板(右侧,点建筑后出现) */
.s3d-panel{position:absolute;right:16px;top:64px;bottom:16px;width:340px;background:rgba(22,26,36,.95);backdrop-filter:blur(14px);border:1px solid var(--accent,var(--gold));border-radius:var(--r);box-shadow:var(--shadow-lg);z-index:6;display:flex;flex-direction:column;opacity:0;transform:translateX(20px);transition:opacity .3s var(--ease),transform .3s var(--ease)}
.s3d-panel.show{opacity:1;transform:translateX(0)}
.s3d-panel[hidden]{display:none}
.s3d-panel-close{position:absolute;top:8px;right:10px;font-size:22px;color:var(--t3);line-height:1;z-index:2}
.s3d-panel-close:hover{color:var(--t)}
.s3d-panel-head{padding:16px 18px 12px;border-bottom:1px solid var(--line)}
.s3d-panel-head .s3d-badge{display:inline-block;padding:2px 9px;border-radius:20px;font-size:10px;font-weight:700;background:color-mix(in srgb,var(--accent,var(--gold)) 22%,transparent);color:var(--accent,var(--gold))}
.s3d-panel-head b{display:block;font-size:15px;color:var(--t);font-weight:700;margin:6px 0 3px;padding-right:24px}
.s3d-panel-head p{font-size:11.5px;color:var(--t3)}
.s3d-panel-tabs{display:flex;border-bottom:1px solid var(--line)}
.s3d-tab{flex:1;padding:10px;font-size:12px;color:var(--t3);border-bottom:2px solid transparent;transition:.2s;font-weight:600}
.s3d-tab:hover{color:var(--t)}
.s3d-tab.on{color:var(--accent,var(--gold));border-bottom-color:var(--accent,var(--gold))}
.s3d-panel-body{flex:1;overflow-y:auto;padding:12px 14px}
.s3d-panel-body[hidden]{display:none}

/* 结构层列表 */
.s3d-layer{display:flex;gap:10px;padding:10px;border-radius:var(--r-s);cursor:pointer;border:1px solid transparent;transition:.2s;margin-bottom:6px;list-style:none}
.s3d-layer:hover{background:var(--card);border-color:var(--line)}
.s3d-layer.on{background:color-mix(in srgb,var(--accent,var(--gold)) 16%,var(--card));border-color:var(--accent,var(--gold))}
.s3d-layer-dot{width:8px;height:8px;border-radius:50%;margin-top:6px;flex-shrink:0;box-shadow:0 0 8px currentColor}
.s3d-layer>div{min-width:0}
.s3d-layer b{display:block;font-size:13px;color:var(--t);font-weight:600}
.s3d-layer span{font-size:11px;color:var(--t3);line-height:1.5;display:block}

/* 辨析题 */
.s3d-empty{color:var(--t3);font-size:12px;text-align:center;padding:20px}
.s3d-q{padding:12px;background:var(--card);border:1px solid var(--line);border-radius:var(--r-s);margin-bottom:10px}
.s3d-q-text{font-size:12.5px;color:var(--t);margin-bottom:8px;line-height:1.6}
.s3d-q-text b{color:var(--gold)}
.s3d-q-opts{display:flex;flex-wrap:wrap;gap:7px}
.s3d-q-opt{padding:6px 12px;border-radius:var(--r-s);background:var(--card2);color:var(--t2);font-size:12px;border:1px solid var(--line);transition:.2s}
.s3d-q-opt:hover:not(:disabled){border-color:var(--gold);color:var(--t)}
.s3d-q-opt:disabled{cursor:default;opacity:.85}
.s3d-q-opt.ok{background:rgba(78,201,168,.18);border-color:var(--ok);color:var(--ok);font-weight:600}
.s3d-q-opt.bad{background:rgba(239,107,107,.18);border-color:var(--bad);color:var(--bad)}
.s3d-q-explain{margin-top:9px;padding:9px;border-radius:var(--r-s);background:var(--bg);font-size:11.5px;color:var(--t2);line-height:1.6}
.s3d-q-explain[hidden]{display:none}
.s3d-q-explain .ok{color:var(--ok)}
.s3d-q-explain .bad{color:var(--bad)}

/* 旧的 Hub 样式(保留兼容,实际未用) */
.s3d-hub{display:none}

/* ============ 建造 HUD(底部进度条+当前层讲解) ============ */
.s3d-build-hud{position:absolute;left:50%;bottom:28px;transform:translateX(-50%) translateY(10px);width:min(520px,90vw);background:rgba(22,26,36,.96);backdrop-filter:blur(14px);border:1px solid var(--gold);border-radius:var(--r);box-shadow:var(--shadow-lg);padding:14px 18px;z-index:7;opacity:0;transition:opacity .3s var(--ease),transform .3s var(--ease)}
.s3d-build-hud.show{opacity:1;transform:translateX(-50%) translateY(0)}
.s3d-build-hud[hidden]{display:none}
.s3d-build-head{display:flex;align-items:center;gap:10px;margin-bottom:8px}
.s3d-build-step{font-size:10px;letter-spacing:.12em;color:var(--gold);font-weight:700;background:rgba(240,200,118,.15);padding:2px 8px;border-radius:20px}
.s3d-build-head b{font-size:14px;color:var(--t);font-weight:700}
.s3d-build-bar{height:5px;background:var(--bg);border-radius:3px;overflow:hidden;margin-bottom:10px}
.s3d-build-bar i{display:block;height:100%;background:var(--grad-gold);border-radius:3px;transition:width .5s var(--ease)}
.s3d-build-layer{min-height:50px}
.s3d-build-layer-num{font-size:11px;color:var(--t3);letter-spacing:.08em}
.s3d-build-layer b{display:block;font-size:15px;color:var(--gold);font-weight:700;margin:2px 0 3px;font-family:"Songti SC","STSong",serif}
.s3d-build-layer p{font-size:12px;color:var(--t2);line-height:1.6}

/* 建造完成 toast */
.s3d-toast{position:absolute;left:50%;top:80px;transform:translateX(-50%) translateY(-20px);background:rgba(78,201,168,.95);color:#0f1117;padding:12px 22px;border-radius:var(--r);font-size:13px;font-weight:600;box-shadow:var(--shadow-lg);z-index:8;opacity:0;transition:opacity .3s var(--ease),transform .3s var(--ease)}
.s3d-toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.s3d-toast b{font-weight:800}

/* 拆除按钮(面板内,关闭按钮旁) */
.s3d-demolish{position:absolute;top:9px;right:42px;font-size:11px;color:var(--t3);padding:3px 9px;border-radius:var(--r-s);background:transparent;border:1px solid var(--line)}
.s3d-demolish:hover{color:var(--bad);border-color:var(--bad)}

/* 侧栏:已建造项样式 */
.s3d-rail-item.built{border-left-color:var(--ok)}
.s3d-rail-item.built .s3d-rail-dot{box-shadow:0 0 6px var(--ok);background:var(--ok)!important}
.s3d-rail-item.built b{color:var(--ok)}