/* 森老师高中物理可视化 · 模型库
   温润教研视觉基线：米白纸感 + 墨绿 + 暖赭，宋体标题、无衬线正文。
   纯静态，不引用任何外部字体或 CDN。 */

:root{
  --paper:#F3F0E8;
  --card:#FFFDF7;
  --ink:#303E34;
  --ink-2:#687361;
  --ink-3:#8B9481;
  --line:#DEDFD0;
  --line-soft:#E9E7DA;
  --brand:#356546;
  --brand-deep:#24482F;
  --brand-soft:#EAF0DF;
  --accent:#AD7838;
  --accent-soft:#F5E9D8;
  --shadow:0 1px 2px rgba(48,62,52,.05), 0 8px 24px -18px rgba(48,62,52,.45);
  --serif:"Source Han Serif SC","Noto Serif SC","Songti SC",STSong,"SimSun",serif;
  --sans:system-ui,-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei","Hiragino Sans GB",sans-serif;
  --radius:14px;
}

/* 关键：卡片自己设了 display:flex，会盖掉浏览器默认的 [hidden]{display:none}，
   所以筛选/搜索必须显式把 hidden 变成真正的不显示 */
[hidden]{display:none !important}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--sans);
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline;text-underline-offset:3px}
h1,h2,h3,h4{font-family:var(--serif);font-weight:700;line-height:1.35;margin:0;letter-spacing:.01em}
p{margin:0}
ul{margin:0;padding:0;list-style:none}
:focus-visible{outline:2px solid var(--brand);outline-offset:3px;border-radius:4px}

.wrap{width:min(1180px,100% - 48px);margin-inline:auto}
@media (max-width:640px){.wrap{width:min(1180px,100% - 32px)}}

.skip{position:absolute;left:-9999px}
.skip:focus{left:16px;top:12px;background:var(--card);padding:8px 14px;border-radius:8px;z-index:99}

/* ── 页头 ───────────────────────────────────── */
.site-head{
  position:sticky;top:0;z-index:30;
  background:rgba(243,240,232,.94);
  backdrop-filter:saturate(1.2) blur(8px);
  border-bottom:1px solid var(--line);
}
.site-head .wrap{
  display:flex;align-items:center;gap:14px;
  height:66px;
}
.brand{display:flex;align-items:center;gap:12px;color:inherit}
.brand:hover{text-decoration:none}
.mark{
  width:38px;height:38px;flex:0 0 38px;border-radius:9px;
  background:var(--brand);color:#F7F5EC;
  display:grid;place-items:center;
  font-family:var(--serif);font-size:21px;line-height:1;
  box-shadow:inset 0 -2px 0 rgba(0,0,0,.16);
}
.brand-txt{display:flex;flex-direction:column;line-height:1.25}
.brand-name{font-family:var(--serif);font-size:17px;font-weight:700;letter-spacing:.02em}
.brand-sub{font-size:12px;color:var(--ink-2);letter-spacing:.06em}

.nav{margin-left:auto;display:flex;align-items:center;gap:6px}
.nav a{
  color:var(--ink-2);font-size:14.5px;padding:7px 12px;border-radius:8px;
}
.nav a:hover{background:var(--brand-soft);color:var(--brand-deep);text-decoration:none}
.nav a[aria-current="page"]{color:var(--brand-deep);background:var(--brand-soft);font-weight:600}

/* ── 首屏 ───────────────────────────────────── */
.hero{padding:60px 0 34px;border-bottom:1px solid var(--line-soft)}
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  font-size:12.5px;letter-spacing:.14em;color:var(--accent);
  text-transform:uppercase;margin-bottom:16px;
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--accent);opacity:.6}
.hero h1{
  font-size:clamp(32px,4.6vw,50px);
  letter-spacing:.02em;
  line-height:1.22;
}
.hero h1 em{font-style:normal;color:var(--brand)}
.hero .lead{
  margin-top:16px;max-width:60ch;
  font-size:16.5px;color:var(--ink-2);line-height:1.8;
}
.stats{
  display:flex;flex-wrap:wrap;gap:34px;margin-top:30px;
}
.stat b{
  display:block;font-family:var(--serif);font-size:28px;color:var(--brand-deep);line-height:1.1;
}
.stat span{font-size:13px;color:var(--ink-2);letter-spacing:.04em}
.hero-note{
  margin-top:26px;display:inline-block;
  background:var(--accent-soft);color:#6B4A20;
  border:1px solid #E8D6BB;border-left:3px solid #D3A96F;border-radius:10px;
  padding:11px 16px;font-size:13.5px;line-height:1.7;max-width:64ch;
}
.hero-note b{font-weight:700}

/* ── 筛选条 ─────────────────────────────────── */
.filters{
  display:flex;flex-wrap:wrap;align-items:center;gap:12px;
  padding:26px 0 20px;
}
.tabs{display:flex;flex-wrap:wrap;gap:8px}
.tab{
  appearance:none;border:1px solid var(--line);background:transparent;
  color:var(--ink-2);font:inherit;font-size:14px;
  padding:7px 15px;border-radius:999px;cursor:pointer;
  transition:background .15s,border-color .15s,color .15s;
}
.tab b{font-weight:600;color:var(--ink-3);margin-left:5px;font-size:12.5px}
.tab:hover{border-color:var(--brand);color:var(--brand-deep)}
.tab[aria-selected="true"]{
  background:var(--brand);border-color:var(--brand);color:#F7F5EC;
}
.tab[aria-selected="true"] b{color:rgba(247,245,236,.75)}
.search{
  margin-left:auto;position:relative;
}
.count{
  font-size:13px;color:var(--ink-3);letter-spacing:.03em;
  margin-left:2px;white-space:nowrap;
}
.count b{color:var(--brand-deep);font-weight:600}
.search input{
  width:250px;max-width:52vw;
  font:inherit;font-size:14px;color:var(--ink);
  background:var(--card);border:1px solid var(--line);border-radius:999px;
  padding:9px 16px 9px 38px;
}
.search input::placeholder{color:var(--ink-3)}
.search svg{position:absolute;left:13px;top:50%;transform:translateY(-50%);opacity:.5}

/* ── 卡片 ───────────────────────────────────── */
.grid{
  display:grid;gap:22px;
  grid-template-columns:repeat(auto-fill,minmax(322px,1fr));
  padding-bottom:12px;
}
@media (max-width:720px){.grid{grid-template-columns:1fr}}

.card{
  position:relative;display:flex;flex-direction:column;
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow);
  transition:transform .18s ease,box-shadow .18s ease,border-color .18s ease;
}
.card:hover{
  transform:translateY(-3px);border-color:#C9CDB6;
  box-shadow:0 2px 4px rgba(48,62,52,.06),0 22px 38px -26px rgba(48,62,52,.55);
}
.thumb{
  position:relative;aspect-ratio:16/9;background:var(--brand-soft);
  border-bottom:1px solid var(--line-soft);overflow:hidden;
}
.thumb img{width:100%;height:100%;object-fit:cover;object-position:top center}
.unit{
  position:absolute;left:12px;top:12px;
  background:rgba(255,253,247,.94);border:1px solid var(--line);
  border-radius:999px;padding:3px 11px;
  font-size:12px;color:var(--brand-deep);letter-spacing:.06em;
}
.live{
  position:absolute;right:12px;top:12px;
  display:inline-flex;align-items:center;gap:5px;
  background:rgba(48,62,52,.78);color:#F7F5EC;
  border-radius:999px;padding:3px 10px 3px 8px;font-size:11.5px;letter-spacing:.08em;
}
.live::before{content:"";width:5px;height:5px;border-radius:50%;background:#A8C98F}

.card-body{padding:17px 18px 18px;display:flex;flex-direction:column;flex:1}
.card h3{font-size:19px;letter-spacing:.01em}
.card h3 a{color:inherit}
.card h3 a:hover{color:var(--brand-deep);text-decoration:none}
.card .desc{
  margin-top:8px;font-size:14px;line-height:1.65;color:var(--ink-2);flex:1;
}
.tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:14px}
.tags li{
  font-size:12px;color:var(--brand-deep);background:var(--brand-soft);
  border-radius:6px;padding:2.5px 8px;letter-spacing:.02em;
}
.card-foot{
  display:flex;align-items:center;justify-content:space-between;
  margin-top:15px;padding-top:13px;border-top:1px dashed var(--line);
}
.topic{font-size:12.5px;color:var(--ink-3);letter-spacing:.04em}
.enter{
  font-size:13.5px;color:var(--brand-deep);font-weight:600;
  display:inline-flex;align-items:center;gap:5px;
}
.enter::after{content:"→";transition:transform .16s ease}
.card:hover .enter::after{transform:translateX(3px)}

.empty{
  padding:56px 0 72px;text-align:center;color:var(--ink-2);font-size:15px;
}

/* ── 页脚 ───────────────────────────────────── */
.site-foot{
  margin-top:56px;border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(234,240,223,.35),rgba(243,240,232,0));
}
.foot-inner{
  display:flex;flex-wrap:wrap;gap:28px;justify-content:space-between;
  padding:34px 0 46px;
}
.foot-brand{display:flex;gap:12px;align-items:flex-start;max-width:44ch}
.foot-brand p{font-size:13px;color:var(--ink-2);line-height:1.75}
.foot-meta{display:flex;flex-direction:column;gap:6px;font-size:12.5px;color:var(--ink-2);text-align:right;align-items:flex-end}
.foot-meta a{color:var(--ink-2)}
.foot-meta a:hover{color:var(--brand-deep)}
@media (max-width:640px){
  .foot-meta{text-align:left;align-items:flex-start}
}

/* ── 登录页 ─────────────────────────────────────── */
.auth{
  max-width:470px;margin:56px auto 72px;
  background:var(--card);border:1px solid var(--line);border-radius:16px;
  padding:32px 30px 26px;box-shadow:var(--shadow);
}
.auth h1{font-size:26px}
.auth-sub{margin-top:10px;font-size:14px;color:var(--ink-2);line-height:1.75}
.field{display:block;margin-top:18px}
.field > span:first-child{display:block;font-size:12.5px;color:var(--ink-2);letter-spacing:.04em;margin-bottom:6px}
.field input{
  width:100%;font:inherit;font-size:16px;color:var(--ink);
  background:#fff;border:1px solid var(--line);border-radius:10px;
  padding:11px 14px;letter-spacing:.06em;
}
.field input:focus{border-color:var(--brand);outline:none;box-shadow:0 0 0 3px rgba(53,101,70,.12)}
.row{display:flex;gap:10px;align-items:stretch}
.row input{flex:1;min-width:0}
.row .btn{white-space:nowrap;padding:0 14px}
.auth-go{width:100%;justify-content:center;margin-top:22px;padding:11px;font-size:15px}
.auth-msg{margin-top:12px;font-size:13.5px;color:var(--ink-2);min-height:1.5em}
.auth-msg.bad{color:#A33B2B}
.auth-note{margin-top:16px;font-size:12px;color:var(--ink-3);line-height:1.7}
@media (max-width:600px){
  .auth{margin:24px auto 40px;padding:24px 18px 20px;border-radius:12px}
}

/* ── 模型页（课件外壳）─────────────────────── */
body.model-page{height:100vh;height:100dvh;display:flex;flex-direction:column;overflow:hidden;background:var(--card)}
.topbar{
  flex:0 0 auto;display:flex;align-items:center;gap:14px;
  height:54px;padding:0 16px;
  background:var(--paper);border-bottom:1px solid var(--line);
  position:relative;z-index:5;
}
.back{
  display:inline-flex;align-items:center;gap:7px;
  font-size:14px;color:var(--ink-2);padding:6px 10px 6px 6px;border-radius:8px;
  white-space:nowrap;
}
.back:hover{background:var(--brand-soft);color:var(--brand-deep);text-decoration:none}
.back svg{flex:0 0 auto}
.tb-title{display:flex;align-items:baseline;gap:10px;min-width:0}
.tb-title b{
  font-family:var(--serif);font-size:17px;font-weight:700;white-space:nowrap;
  overflow:hidden;text-overflow:ellipsis;
}
.tb-title span{font-size:12px;color:var(--ink-3);letter-spacing:.06em;white-space:nowrap}
.tb-actions{margin-left:auto;display:flex;align-items:center;gap:7px}
.btn{
  appearance:none;font:inherit;font-size:13.5px;cursor:pointer;
  display:inline-flex;align-items:center;gap:6px;
  background:var(--card);color:var(--ink);border:1px solid var(--line);
  border-radius:8px;padding:6px 12px;line-height:1.4;
  transition:border-color .15s,background .15s,color .15s;
}
.btn:hover{border-color:var(--brand);color:var(--brand-deep);background:var(--brand-soft)}
.btn.solid{background:var(--brand);border-color:var(--brand);color:#F7F5EC}
.btn.solid:hover{background:var(--brand-deep);border-color:var(--brand-deep);color:#fff}

.frame{position:relative;flex:1 1 auto;min-height:0;background:var(--card)}
.frame iframe{position:absolute;inset:0;width:100%;height:100%;border:0;display:block}
.veil{
  position:absolute;inset:0;display:grid;place-items:center;
  background:var(--card);color:var(--ink-2);font-size:14px;
  transition:opacity .35s ease;z-index:2;
}
.veil.off{opacity:0;pointer-events:none}
.spin{
  width:26px;height:26px;border-radius:50%;
  border:2px solid var(--line);border-top-color:var(--brand);
  animation:spin .9s linear infinite;margin:0 auto 12px;
}
@keyframes spin{to{transform:rotate(360deg)}}

/* 底部备案条（模型页常驻，满足每页挂备案号） */
.footbar{
  flex:0 0 auto;display:flex;align-items:center;justify-content:space-between;gap:12px;
  height:27px;padding:0 14px;background:var(--paper);
  border-top:1px solid var(--line);
  font-size:11.5px;color:var(--ink-3);letter-spacing:.02em;
}
.footbar span,.footbar a{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.footbar a{color:var(--ink-3)}
.footbar a:hover{color:var(--brand-deep)}
@media (max-width:600px){.footbar span{display:none}.footbar{justify-content:flex-end}}

/* 说明抽屉 */
.overlay{
  position:fixed;inset:0;background:rgba(48,62,52,.34);
  opacity:0;pointer-events:none;transition:opacity .22s ease;z-index:40;
}
.overlay.on{opacity:1;pointer-events:auto}
.drawer{
  position:fixed;top:0;right:0;height:100%;width:min(420px,100%);
  background:var(--card);border-left:1px solid var(--line);
  transform:translateX(102%);transition:transform .28s cubic-bezier(.22,.61,.36,1);
  z-index:41;display:flex;flex-direction:column;
  box-shadow:-18px 0 40px -30px rgba(48,62,52,.6);
}
.drawer.on{transform:translateX(0)}
.drawer-head{
  display:flex;align-items:flex-start;gap:12px;
  padding:22px 24px 16px;border-bottom:1px solid var(--line-soft);
}
.drawer-head h2{font-size:19px;flex:1}
.drawer-body{padding:20px 24px 32px;overflow:auto}
.drawer-body h3{
  font-family:var(--sans);font-size:12.5px;letter-spacing:.12em;color:var(--accent);
  margin:20px 0 8px;
}
.drawer-body h3:first-child{margin-top:0}
.drawer-body p{font-size:14px;color:var(--ink-2);line-height:1.8}
.drawer-body .tags{margin-top:4px}
.x{
  appearance:none;border:0;background:transparent;cursor:pointer;
  font-size:20px;line-height:1;color:var(--ink-3);padding:4px 6px;border-radius:6px;
}
.x:hover{background:var(--brand-soft);color:var(--ink)}

/* ── 关于页 ─────────────────────────────────── */
.article{max-width:760px;padding:48px 0}
.article h1{font-size:clamp(26px,3.6vw,36px)}
.article h2{margin-top:44px;font-size:21px;padding-bottom:10px;border-bottom:1px solid var(--line-soft)}
.article p{margin-top:14px;color:var(--ink-2);line-height:1.85;font-size:15.5px}
.article ul{margin-top:14px;display:grid;gap:8px}
.article ul li{padding-left:18px;position:relative;color:var(--ink-2);font-size:15px;line-height:1.75}
.article ul li::before{content:"";position:absolute;left:0;top:.72em;width:6px;height:6px;border-radius:2px;background:var(--accent);opacity:.65}
.lede{font-size:17px;color:var(--ink);line-height:1.85;margin-top:18px}
.tbl-wrap{overflow-x:auto;margin-top:18px}
table{border-collapse:collapse;width:100%;font-size:14px}
th,td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line-soft)}
th{font-size:12.5px;letter-spacing:.08em;color:var(--ink-3);font-weight:600;background:rgba(234,240,223,.4)}
td:first-child{color:var(--ink-3);white-space:nowrap}
td b{font-weight:600;color:var(--ink)}
.meta-list{display:grid;gap:10px;margin-top:18px}
.meta-list div{display:flex;gap:10px;font-size:14px;color:var(--ink-2)}
.meta-list span:first-child{color:var(--ink-3);min-width:5.5em}

@media (max-width:600px){
  .site-head .wrap{height:58px;gap:8px}
  .brand-name{font-size:15px}
  .brand-sub{display:none}
  .nav a{padding:6px 8px;font-size:13.5px}
  .hero{padding:38px 0 24px}
  .stats{gap:22px}
  .stat b{font-size:23px}
  .search{margin-left:0;width:100%}
  .search input{width:100%;max-width:none}
  .topbar{height:auto;flex-wrap:wrap;padding:8px 12px;gap:8px}
  .tb-title b{font-size:15px;white-space:normal}
  .tb-actions{margin-left:0;width:100%}
  .btn{padding:5px 10px;font-size:13px}
  .article{padding:32px 0}
}