/* ===== 朱老师的未来实验室 · 淡绿清新主题 ===== */
:root{
  --g700:#157a4b; --g600:#1f9d63; --g550:#27ab6c; --g500:#34b97e; --g400:#5fd39c; --g300:#8fe3bd;
  --g50:#f1fbf6; --g100:#e3f7ec; --g150:#d4f3e3;
  --ink:#15382b; --sub:#52766a; --line:#e2efe9;
  --bg:#ffffff; --bg2:#f6fcf9;
  --shadow:0 12px 34px -16px rgba(31,157,99,.30);
  --shadow-sm:0 6px 18px -10px rgba(31,157,99,.28);
  --radius:18px; --radius-sm:12px;
  --maxw:1180px;
  --sbj-物理:#2bb3a3; --sbj-化学:#5bbf5b; --sbj-生物:#3fa66a; --sbj-地理:#2f9bb5; --sbj-其他:#7d9b8e;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:"PingFang SC","Microsoft YaHei","Sarasa Gothic SC",system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
  color:var(--ink); background:var(--bg2); line-height:1.6; -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 22px}
.btn{
  display:inline-flex;align-items:center;gap:8px;font-weight:600;font-size:15px;
  padding:12px 22px;border-radius:999px;border:0;cursor:pointer;transition:.2s; white-space:nowrap;
}
.btn-primary{background:linear-gradient(135deg,var(--g500),var(--g600));color:#fff;box-shadow:var(--shadow-sm)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:var(--shadow)}
.btn-ghost{background:#fff;color:var(--g600);border:1.5px solid var(--g300)}
.btn-ghost:hover{border-color:var(--g500);background:var(--g50)}
.btn-line{background:transparent;color:var(--g600);border:1.5px solid var(--g400)}
.btn-line:hover{background:var(--g100)}

/* ===== 导航 ===== */
.nav{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.82);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:19px;color:var(--g600)}
.logo .mark{width:34px;height:34px;border-radius:10px;display:grid;place-items:center;background:linear-gradient(135deg,var(--g400),var(--g600));color:#fff;font-size:18px;box-shadow:var(--shadow-sm)}
.nav-links{display:flex;gap:28px;align-items:center}
.nav-links a{color:var(--sub);font-weight:500;font-size:15px}
.nav-links a:hover{color:var(--g600)}
.nav-cta{display:flex;gap:12px;align-items:center}

/* ===== Hero ===== */
.hero{position:relative;overflow:hidden;
  background:
    radial-gradient(900px 420px at 88% -8%, rgba(95,211,156,.45), transparent 60%),
    radial-gradient(700px 380px at 8% 110%, rgba(47,155,181,.18), transparent 60%),
    linear-gradient(180deg,#eafaf2, #f6fcf9);
  padding:72px 0 64px;
}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:36px;align-items:center}
.eyebrow{display:inline-flex;align-items:center;gap:8px;background:#fff;border:1px solid var(--g300);
  color:var(--g600);font-weight:600;font-size:13px;padding:6px 14px;border-radius:999px;box-shadow:var(--shadow-sm)}
.hero h1{font-size:clamp(30px,4.4vw,50px);line-height:1.18;margin:20px 0 16px;letter-spacing:-.5px;font-weight:800}
.hero h1 .hl{background:linear-gradient(120deg,var(--g500),var(--g600));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{font-size:17px;color:var(--sub);max-width:520px;margin-bottom:26px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap}
.hero-badge{margin-top:22px;display:inline-flex;align-items:center;gap:8px;color:var(--sub);font-size:14px}
.hero-badge .dot{width:8px;height:8px;border-radius:50%;background:var(--g500);box-shadow:0 0 0 4px rgba(52,185,126,.18)}

/* hero 装饰插画 */
.hero-art{position:relative;aspect-ratio:1/1;display:grid;place-items:center}
.hero-art svg{width:100%;height:100%;filter:drop-shadow(0 18px 40px rgba(31,157,99,.25))}
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-12px)}}
.orbit{transform-origin:center;animation:spin 26s linear infinite}
.orbit.rev{animation-duration:38s;animation-direction:reverse}
.floaty{animation:float 6s ease-in-out infinite}

/* ===== 区块标题 ===== */
.section{padding:56px 0}
.section-head{display:flex;align-items:flex-end;justify-content:space-between;margin-bottom:26px;gap:16px;flex-wrap:wrap}
.section-head h2{font-size:27px;font-weight:800;letter-spacing:-.3px}
.section-head .sub{color:var(--sub);font-size:15px;margin-top:6px}
.tag-new{display:inline-block;background:var(--g600);color:#fff;font-size:11px;font-weight:700;padding:2px 8px;border-radius:6px;margin-left:8px;vertical-align:middle}

/* ===== 科目卡片（四块封面，参考铜匠） ===== */
.subjects{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.sc{display:flex;align-items:center;gap:14px;background:#fff;border:1px solid var(--line);
  border-radius:var(--radius);padding:18px 20px;min-height:128px;transition:.2s;cursor:pointer;overflow:hidden;text-decoration:none;color:inherit}
.sc:hover{transform:translateY(-4px);box-shadow:var(--shadow);border-color:var(--g300)}
.sc .tx{flex:1;min-width:0}
.sc .tx small{display:block;font-size:11px;font-weight:700;letter-spacing:1.5px;text-transform:uppercase;color:var(--sub);opacity:.65}
.sc .tx h3{font-size:23px;font-weight:800;margin:3px 0 6px}
.sc .tx p{font-size:13px;color:var(--sub);line-height:1.5}
.sc .n{margin-top:10px;font-size:13px;font-weight:700;color:var(--g600);display:inline-flex;align-items:center;gap:4px}
.sc img{width:104px;height:104px;object-fit:cover;border-radius:14px;flex:none;box-shadow:var(--shadow-sm)}

/* ===== 实验卡片网格 ===== */
.filters{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:24px}
.chip{background:#fff;border:1px solid var(--line);color:var(--sub);font-weight:600;font-size:14px;
  padding:8px 16px;border-radius:999px;cursor:pointer;transition:.18s}
.chip:hover{border-color:var(--g300);color:var(--g600)}
.chip.active{background:linear-gradient(135deg,var(--g500),var(--g600));color:#fff;border-color:transparent;box-shadow:var(--shadow-sm)}

.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;
  transition:.2s;display:flex;flex-direction:column}
.card:hover{transform:translateY(-5px);box-shadow:var(--shadow);border-color:var(--g300)}
.card-cover{position:relative;aspect-ratio:16/10;display:grid;place-items:center;color:#fff;font-size:54px}
.card-cover .tag{position:absolute;top:12px;left:12px;background:rgba(255,255,255,.92);color:var(--g600);
  font-weight:700;font-size:12px;padding:4px 11px;border-radius:999px}
.card-cover .new{position:absolute;top:12px;right:12px;background:var(--g600);color:#fff;font-size:11px;font-weight:700;padding:3px 9px;border-radius:6px}
.card-cover .type-pill{position:absolute;bottom:12px;left:12px;background:rgba(255,255,255,.9);color:var(--g700);font-size:11px;font-weight:700;padding:3px 10px;border-radius:999px;backdrop-filter:blur(2px)}
.card-body{padding:18px 18px 20px;display:flex;flex-direction:column;gap:8px;flex:1}
.card-body h3{font-size:17px;font-weight:700;line-height:1.35}
.card-body .meta{color:var(--sub);font-size:12.5px}
.card-body .summary{color:#5c7068;font-size:14px;flex:1;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.card-body .start{margin-top:6px;color:var(--g600);font-weight:700;font-size:14px;display:inline-flex;align-items:center;gap:6px}
.card:hover .start{gap:10px}
.empty{grid-column:1/-1;text-align:center;color:var(--sub);padding:50px 0}

/* ===== CTA banner + footer ===== */
.cta{background:linear-gradient(135deg,var(--g500),var(--g600));color:#fff;border-radius:26px;padding:42px 40px;
  display:flex;align-items:center;justify-content:space-between;gap:24px;flex-wrap:wrap;margin:10px 0 56px;box-shadow:var(--shadow)}
.cta h2{font-size:24px;font-weight:800}
.cta p{opacity:.92;margin-top:6px}
.cta .btn-white{background:#fff;color:var(--g600)}

footer{background:#0f3024;color:#cfe9dd;padding:40px 0 26px;margin-top:10px}
.foot-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1fr;gap:28px}
footer h4{color:#fff;font-size:15px;margin-bottom:12px}
footer a{display:block;color:#a9cfc1;font-size:14px;margin-bottom:8px}
footer a:hover{color:#fff}
.foot-brand p{color:#9cc4b6;font-size:14px;margin-top:10px;max-width:300px}
.foot-bottom{border-top:1px solid rgba(255,255,255,.12);margin-top:28px;padding-top:18px;color:#8fb6a8;font-size:13px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px}

/* ===== 详情页（参考铜匠布局，去掉右侧操作栏与页脚社交/赞赏） ===== */
.exp-page{padding:24px 0 50px}
.breadcrumb{color:var(--sub);font-size:14px;margin-bottom:16px}
.breadcrumb a:hover{color:var(--g600)}
.exp-head{margin-bottom:18px}
.exp-head .pills{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}
.exp-head .tag{background:var(--g100);color:var(--g600);font-weight:700;font-size:13px;padding:5px 13px;border-radius:999px}
.exp-head .type-pill2{background:var(--g700);color:#fff;font-weight:700;font-size:12px;padding:5px 13px;border-radius:999px}
.exp-head .step-pill{background:#fff;color:var(--g600);border:1.5px solid var(--g300);font-weight:700;font-size:12px;padding:4px 13px;border-radius:999px}
.exp-head h1{font-size:clamp(24px,3.2vw,32px);font-weight:800;letter-spacing:-.3px;line-height:1.25}

/* 实验舞台：工具栏 + 框 + 骨架屏 */
.exp-stage{border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;background:#fff;box-shadow:var(--shadow-sm)}
.exp-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:11px 16px;background:linear-gradient(135deg,#f1faf4,#e6f4ec);border-bottom:1px solid var(--line)}
.exp-stage-title{font-weight:700;color:var(--g700);font-size:14px}
.exp-actions{display:flex;gap:8px}
.exp-btn{font:inherit;font-size:13px;font-weight:600;color:var(--g700);background:#fff;border:1.5px solid var(--g300);border-radius:9px;padding:7px 13px;cursor:pointer;transition:.15s;white-space:nowrap}
.exp-btn:hover{background:var(--g500);color:#fff;border-color:var(--g500)}
.exp-frame{position:relative;overflow:hidden;background:linear-gradient(135deg,#f1faf4,#e3f5ea)}
.exp-frame iframe{width:100%;height:72vh;border:0;display:block;background:#fbfdfc}
.exp-skeleton{position:absolute;inset:0;z-index:5;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;background:linear-gradient(135deg,#f1faf4,#e3f5ea);color:var(--g600);font-weight:600;transition:opacity .35s}
.exp-skeleton.hidden{opacity:0;pointer-events:none}
.sk-spin{width:40px;height:40px;border:4px solid var(--g200);border-top-color:var(--g500);border-radius:50%;animation:spin 1s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.exp-frame:fullscreen{height:100vh;display:flex;background:#fff}
.exp-frame:fullscreen iframe{height:100%}
.exp-cap{color:var(--sub);font-size:13px;margin-top:10px;text-align:center}

/* 信息栏：引导问题卡（醒目）+ 教材出处 */
.exp-info{display:grid;grid-template-columns:1.3fr 1fr;gap:18px;margin-top:22px}
.info-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:20px 22px;box-shadow:var(--shadow-sm)}
.info-card h4{font-size:15px;color:var(--g600);margin-bottom:10px}
.info-card .q{font-size:15px;color:var(--ink);line-height:1.75}
.info-card .book{font-size:15px;color:var(--sub);line-height:1.7}
.info-card.lesson{background:linear-gradient(135deg,#eafaef,#d6f2e1);border-color:var(--g300);border-left:5px solid var(--g500)}
.info-card.lesson .lesson-badge{display:inline-block;background:var(--g500);color:#fff;font-size:13px;font-weight:700;padding:5px 13px;border-radius:999px;margin-bottom:12px}
.info-card.lesson .q{font-size:16px;font-weight:600;color:#1f6b46;line-height:1.85}

.related{margin-top:40px}
.related h3{font-size:22px;font-weight:800;margin-bottom:18px;letter-spacing:-.3px}
.exp-loading{display:grid;place-items:center;height:72vh;color:var(--sub)}
.exp-err{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:40px;text-align:center;color:var(--sub)}

/* ===== 后台 ===== */
.admin-wrap{max-width:880px;margin:0 auto;padding:30px 22px 60px}
.admin-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow-sm)}
.admin-card h2{font-size:22px;margin-bottom:6px}
.admin-card .hint{color:var(--sub);font-size:14px;margin-bottom:20px}
.field{margin-bottom:16px}
.field label{display:block;font-weight:600;font-size:14px;margin-bottom:6px}
.field input,.field select,.field textarea{width:100%;padding:11px 13px;border:1.5px solid var(--line);border-radius:var(--radius-sm);font-size:14px;font-family:inherit;color:var(--ink);background:#fff}
.field input:focus,.field select:focus,.field textarea:focus{outline:none;border-color:var(--g400)}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.admin-msg{font-size:14px;margin-top:10px;min-height:18px}
.admin-msg.ok{color:var(--g600)} .admin-msg.err{color:#d9534f}
.admin-list{margin-top:30px}
.admin-item{display:flex;align-items:center;gap:12px;padding:14px;border:1px solid var(--line);border-radius:var(--radius-sm);margin-bottom:10px;background:#fff}
.admin-item .thumb{width:64px;height:44px;border-radius:8px;display:grid;place-items:center;color:#fff;font-size:20px;flex:none}
.admin-item .info{flex:1;min-width:0}
.admin-item .info b{font-size:15px}
.admin-item .info small{color:var(--sub);display:block}
.admin-item .del{margin-left:auto;background:#fff;border:1px solid #f0c9c5;color:#d9534f;border-radius:9px;padding:8px 14px;cursor:pointer;font-weight:600;font-size:13px}
.admin-item .del:hover{background:#fff3f2}
.admin-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:18px}
.logout{background:none;border:1px solid var(--line);color:var(--sub);border-radius:9px;padding:8px 14px;cursor:pointer;font-weight:600}
.logout:hover{border-color:var(--g300);color:var(--g600)}
.notice{background:var(--g50);border:1px solid var(--g150);border-radius:var(--radius-sm);padding:12px 14px;color:var(--sub);font-size:13px;margin-bottom:18px}

/* ===== 响应式 ===== */
@media(max-width:980px){
  .hero-grid{grid-template-columns:1fr}
  .hero-art{max-width:380px;margin:0 auto}
  .subjects{grid-template-columns:repeat(2,1fr)}
  .grid{grid-template-columns:repeat(2,1fr)}
  .foot-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:620px){
  .nav-links{display:none}
  .subjects{grid-template-columns:1fr}
  .grid{grid-template-columns:1fr}
  .exp-info{grid-template-columns:1fr}
  .exp-toolbar{flex-wrap:wrap}
  .exp-frame iframe{height:60vh}
  .row2{grid-template-columns:1fr}
  .cta{flex-direction:column;align-items:flex-start}
  .foot-grid{grid-template-columns:1fr}
}