/* ============================================================
   物理互动课堂 · 共享样式
   设计语言参考 lever.html：纸面/黑板风，手写字体点缀
   ============================================================ */
:root{
  --paper:#f5efdd; --paper2:#fffdf4; --ink:#0f372e; --ink2:#5a6398;
  --red:#d64530; --yellow:#f59e0b; --green:#2f7d5d; --blue:#3b6bd6;
  --board:#28503f; --board2:#1d3b30; --chalk:#f2efe2; --chalk-dim:#b8cab9;
  --hard:6px 6px 0 rgba(15,55,46,.14);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:'Noto Sans SC',sans-serif;color:var(--ink);line-height:1.75;
  background:
    radial-gradient(900px 500px at 85% -5%,rgba(214,69,48,.07),transparent 60%),
    radial-gradient(700px 500px at -10% 30%,rgba(15,55,46,.06),transparent 60%),
    linear-gradient(rgba(15,55,46,.065) 1px,transparent 1px),
    linear-gradient(90deg,rgba(15,55,46,.065) 1px,transparent 1px),
    var(--paper);
  background-size:auto,auto,24px 24px,24px 24px,auto;
  -webkit-tap-highlight-color:transparent;
}
::selection{background:var(--yellow);color:var(--ink)}
.wrap{max-width:1160px;margin:0 auto;padding:0 max(20px, env(safe-area-inset-right, 20px)) 0 max(20px, env(safe-area-inset-left, 20px))}
h1,h2,h3,h4{font-family:'ZCOOL QingKe HuangYou',sans-serif;font-weight:400;letter-spacing:1.5px}
.mono{font-family:'IBM Plex Mono',monospace}
.hand{font-family:'Ma Shan Zheng',cursive}
img,svg{max-width:100%}
button{font-family:inherit}

/* ---------- 顶部进度条 & 导航 ---------- */
#pbar{position:fixed;top:0;left:0;height:3px;background:var(--red);width:0;z-index:99}
nav{position:sticky;top:0;z-index:90;background:rgba(238,246,242,.94);backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px);border-bottom:2px solid var(--ink);padding-top:env(safe-area-inset-top, 0px)}
.nav-in{display:flex;align-items:center;gap:18px;height:56px}
.logo{display:flex;align-items:center;gap:10px;font-family:'ZCOOL QingKe HuangYou';font-size:20px;white-space:nowrap;color:var(--ink);text-decoration:none}
.logo-box{width:32px;height:32px;background:var(--ink);color:var(--yellow);display:grid;place-items:center;border-radius:6px;box-shadow:2px 2px 0 var(--red);font-size:17px}
.nav-links{display:flex;gap:4px;margin-left:auto;overflow-x:auto;scrollbar-width:none}
.nav-links::-webkit-scrollbar{display:none}
.nav-links a{color:var(--ink);text-decoration:none;font-size:14px;font-weight:500;padding:6px 10px;white-space:nowrap;border-radius:6px;position:relative;transition:.2s}
.nav-links a:hover{background:rgba(15,55,46,.08)}
.nav-links a.active{color:var(--red);font-weight:700}
.nav-links a.active::after{content:'';position:absolute;left:10px;right:10px;bottom:2px;height:3px;background:var(--red);border-radius:2px}
.nav-side{display:flex;gap:8px;align-items:center}
.install-btn{display:none;align-items:center;gap:6px;border:2px solid var(--ink);background:var(--yellow);color:var(--ink);
  font-size:13px;font-weight:800;padding:5px 12px;border-radius:8px;cursor:pointer;box-shadow:2px 2px 0 rgba(15,55,46,.3)}
.install-btn.show{display:inline-flex}

/* ---------- 通用 ---------- */
.panel{background:var(--paper2);border:2px solid var(--ink);border-radius:10px;box-shadow:var(--hard)}
.btn{display:inline-flex;align-items:center;gap:6px;border:2px solid var(--ink);background:#fff;color:var(--ink);
  padding:8px 18px;border-radius:8px;font-size:14px;font-weight:700;font-family:inherit;cursor:pointer;
  box-shadow:3px 3px 0 var(--ink);transition:.15s}
.btn:hover{transform:translate(-1px,-1px);box-shadow:4px 4px 0 var(--ink)}
.btn:active{transform:translate(2px,2px);box-shadow:0 0 0 var(--ink)}
.btn.red{background:var(--red);color:#fff}
.btn.yellow{background:var(--yellow)}
.btn:disabled{opacity:.45;cursor:not-allowed;transform:none}
.chip{display:inline-flex;align-items:center;gap:6px;border:1.6px solid var(--ink);padding:3px 12px;border-radius:999px;font-size:13px;font-weight:700;background:#fff}
.tag{font-family:'IBM Plex Mono';font-size:12px;letter-spacing:1px;color:var(--red)}
.shead{display:flex;align-items:flex-end;gap:18px;flex-wrap:wrap;margin-bottom:32px;border-bottom:3px dashed rgba(15,55,46,.25);padding-bottom:16px}
.sec-no{font-family:'IBM Plex Mono';font-size:15px;color:var(--red);border:2px solid var(--red);padding:2px 9px;border-radius:5px;background:#fff;flex:none}
.sec-title{font-size:clamp(28px,3.6vw,42px);line-height:1.1}
.sec-sub{font-size:14px;color:var(--ink2);margin-top:4px}
.sec-note{margin-left:auto;font-family:'Ma Shan Zheng';font-size:21px;color:var(--red);transform:rotate(-2deg)}
section{padding:64px 0}
section.tight{padding-top:26px}
.stamp{display:inline-block;font-family:'ZCOOL QingKe HuangYou';color:var(--red);border:3px solid var(--red);
  padding:4px 16px;border-radius:8px;letter-spacing:6px;font-size:26px;opacity:0;pointer-events:none}
.stamp.show{animation:stampIn .5s cubic-bezier(.2,1.8,.4,1) forwards}
@keyframes stampIn{0%{opacity:0;transform:rotate(-8deg) scale(2.2)}100%{opacity:.95;transform:rotate(-8deg) scale(1)}}
.js .reveal{opacity:0;transform:translateY(26px);transition:opacity .7s ease,transform .7s ease}
.js .reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}
.note-line{font-size:13px;color:var(--ink2);margin-top:12px;padding-left:14px;border-left:4px solid var(--yellow)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:22px}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}

/* ---------- 页面 HERO（主题页） ---------- */
.page-hero{padding:44px 0 30px;position:relative;overflow:hidden}
.page-hero .crumb a{color:var(--ink2);text-decoration:none;font-size:13px;font-weight:600}
.page-hero .crumb a:hover{color:var(--red)}
.page-hero h1{font-size:clamp(44px,7vw,84px);line-height:1;margin:8px 0 4px;display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.page-hero .kicker{display:flex;align-items:center;gap:10px;font-family:'IBM Plex Mono';font-size:13px;letter-spacing:2px;color:var(--red);margin-bottom:10px}
.page-hero .kicker::before{content:'';width:12px;height:12px;background:var(--red)}
.page-hero .sub{font-size:15.5px;color:var(--ink2);max-width:70ch}
.page-hero .tags{display:flex;gap:10px;flex-wrap:wrap;margin-top:14px}
.uline{width:170px;height:9px;margin:6px 0 10px;background:var(--red);border-radius:5px;transform:skewX(-12deg)}
.fsym{position:absolute;font-family:'IBM Plex Mono';font-weight:600;color:var(--ink);opacity:.1;user-select:none;pointer-events:none;animation:drift 10s ease-in-out infinite alternate}
@keyframes drift{from{transform:translate(0,0) rotate(-6deg)}to{transform:translate(18px,-26px) rotate(8deg)}}

/* ---------- 知识卡片 ---------- */
.kgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:18px}
.kcard{border:2px solid var(--ink);border-radius:10px;background:#fff;padding:16px 18px;box-shadow:4px 4px 0 rgba(15,55,46,.12);position:relative;transition:.2s}
.kcard:hover{transform:translateY(-3px)}
.kcard h4{font-size:19px;margin-bottom:6px;display:flex;align-items:center;gap:8px}
.kcard h4 .ki{width:30px;height:30px;border-radius:8px;display:grid;place-items:center;font-size:16px;background:rgba(247,201,72,.45)}
.kcard p{font-size:14px;color:#3a4378}
.kcard .kex{margin-top:10px;font-size:12.5px;background:rgba(59,107,214,.08);border-left:3px solid var(--blue);padding:7px 10px;border-radius:0 7px 7px 0;color:#33528f}
.kcard:hover .kex{background:rgba(59,107,214,.12)}
.kcard.green h4 .ki{background:rgba(47,125,93,.16)}
.kcard.green .kex{border-color:var(--green);background:rgba(47,125,93,.08);color:#245e46}
.kcard.red h4 .ki{background:rgba(214,69,48,.14)}
.kcard.red .kex{border-color:var(--red);background:rgba(214,69,48,.07);color:#8f2418}

/* ---------- 公式 ---------- */
.fx-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:18px}
.fx-card{position:relative;background:var(--paper2);border:2px solid var(--ink);border-radius:10px;padding:16px 20px 14px;box-shadow:var(--hard)}
.fx-card .fx-name{font-size:14px;font-weight:800;display:flex;align-items:center;gap:8px;margin-bottom:6px}
.fx-card .fx-name .em{font-size:18px}
.fx-big{font-family:'ZCOOL QingKe HuangYou';font-size:clamp(24px,3vw,34px);text-align:center;padding:8px 6px 4px;color:var(--ink);border:2px dashed rgba(15,55,46,.3);border-radius:9px;background:#fff}
.fx-big .t{position:relative;cursor:help;padding:0 2px;border-bottom:3px dotted var(--red);font-style:italic}
.fx-big .t::after{content:attr(data-tip);position:absolute;left:50%;bottom:112%;transform:translateX(-50%) scale(.8);
  background:var(--ink);color:#fff;font-size:12px;font-family:'Noto Sans SC';font-style:normal;padding:5px 10px;border-radius:6px;white-space:nowrap;opacity:0;pointer-events:none;transition:.2s;z-index:9}
.fx-big .t:hover::after,.fx-big .t:active::after{opacity:1;transform:translateX(-50%) scale(1)}
.fx-vars{margin-top:10px;font-size:12.5px;color:var(--ink2)}
.fx-vars b{color:var(--ink)}
.fx-sub{margin-top:6px;font-size:12.5px}
.deriv{display:flex;gap:10px;flex-wrap:wrap;margin-top:8px}
.deriv span{font-family:'IBM Plex Mono';font-size:13px;background:rgba(15,55,46,.07);border:1.5px dashed var(--ink2);padding:3px 12px;border-radius:7px}

/* ---------- 应用卡片 ---------- */
.app-card{position:relative;border:2px solid var(--ink);background:#fff;border-radius:10px;padding:14px 16px;display:flex;gap:12px;align-items:flex-start;box-shadow:4px 4px 0 rgba(15,55,46,.12);transition:.2s}
.app-card:hover{transform:translateY(-3px) rotate(-.4deg)}
.app-card .ae{font-size:26px;line-height:1.2}
.app-card h5{font-size:16px;margin-bottom:2px}
.app-card p{font-size:13px;color:var(--ink2)}
@keyframes pop2{0%{opacity:1;transform:scale(1)}100%{opacity:0;transform:scale(1.6)}}

/* ---------- 黑板·技巧 ---------- */
.board-sec{background:
  radial-gradient(ellipse at 20% 10%,rgba(255,255,255,.06),transparent 50%),
  radial-gradient(ellipse at 80% 90%,rgba(255,255,255,.05),transparent 50%),
  linear-gradient(var(--board),var(--board2));
  color:var(--chalk);border-top:6px solid #8b5a2b;border-bottom:6px solid #8b5a2b}
.board-sec .sec-title{color:var(--chalk)}
.board-sec .sec-sub{color:var(--chalk-dim)}
.board-sec .sec-no{color:var(--yellow);border-color:var(--yellow);background:transparent}
.board-sec .shead{border-color:rgba(242,239,226,.3)}
.board-sec .sec-note{color:var(--yellow)}
.t-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:18px}
.chalk-panel{border:2px dashed rgba(242,239,226,.4);border-radius:12px;padding:20px;background:rgba(0,0,0,.12)}
.chalk-panel h3{color:var(--yellow);font-size:21px;margin-bottom:6px;letter-spacing:2px}
.chalk-panel .sub{font-size:13px;color:var(--chalk-dim);margin-bottom:12px}
.oly-panel{border-color:rgba(247,201,72,.5);background:rgba(247,201,72,.07)}
.oly-list{display:grid;gap:10px;margin-top:10px}
.oly-item{background:rgba(0,0,0,.18);border:1.5px dashed rgba(247,201,72,.35);border-radius:8px;padding:10px 14px}
.oly-title{color:var(--yellow);font-size:14px;display:block;margin-bottom:4px}
.oly-desc{font-size:13.5px;color:var(--chalk);line-height:1.6}
.m-math{font-family:'IBM Plex Mono','Noto Sans SC',monospace;padding:0 2px;font-style:normal}
.m-math sub{font-size:.78em;vertical-align:-.2em}
.m-math sup{font-size:.78em;vertical-align:.35em}
.board-sec .btn{background:transparent;color:var(--chalk);border-color:var(--chalk);box-shadow:3px 3px 0 rgba(0,0,0,.4)}
.board-sec .btn:hover{background:rgba(255,255,255,.1)}
.board-sec .btn.yellow{background:var(--yellow);color:var(--ink);border-color:var(--ink)}
.steps{counter-reset:st;display:grid;gap:10px;margin-top:12px;list-style:none}
.steps li{display:flex;gap:12px;align-items:flex-start;font-size:14.5px}
.steps li::before{counter-increment:st;content:counter(st);flex:none;width:26px;height:26px;border-radius:50%;background:var(--yellow);color:var(--ink);font-weight:900;display:grid;place-items:center;font-size:14px}
.mistake{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:14px;margin-top:14px}
.mistake div{border:1.6px solid rgba(242,239,226,.35);border-radius:9px;padding:12px 14px;font-size:13.5px}
.mistake .no{color:#ff9d8a;font-weight:700}
.mistake .yes{color:#9fe0b8;font-weight:700}
.jue-card{position:relative;max-width:760px;margin:26px auto 0;background:var(--yellow);padding:26px 34px;transform:rotate(-1deg);
  box-shadow:8px 10px 0 rgba(15,55,46,.18);border:2px solid var(--ink);border-radius:4px}
.jue-card::before{content:'📌 口诀';position:absolute;top:-14px;left:24px;background:var(--red);color:#fff;font-family:'Noto Sans SC';
  font-size:12px;font-weight:800;padding:3px 12px;border-radius:8px;transform:rotate(-2deg)}
.board-sec .jue-card{background:var(--paper2);color:var(--ink);transform:rotate(-1deg)}
.jue-card p{font-family:'Ma Shan Zheng';font-size:clamp(17px,2.2vw,23px);line-height:2.1}

/* ---------- 经典例题面板 ---------- */
.ex-panel{background:rgba(0,0,0,.22);border-color:rgba(247,201,72,.45);margin-top:6px}
.ex-head{display:flex;justify-content:space-between;align-items:center;border-bottom:1.5px dashed rgba(242,239,226,.25);padding-bottom:10px;margin-bottom:14px;flex-wrap:wrap;gap:8px}
.ex-list{display:grid;gap:18px}
.ex-card{background:rgba(255,255,255,.05);border:1.6px solid rgba(242,239,226,.25);border-radius:10px;padding:16px 18px}
.ex-top{display:flex;align-items:center;gap:10px;margin-bottom:10px;flex-wrap:wrap}
.ex-badge{display:inline-block;padding:3px 9px;border-radius:6px;font-size:12px;font-weight:800;letter-spacing:1px}
.ex-badge.zhongkao{background:rgba(47,125,93,.9);color:#fff;border:1px solid #9fe0b8}
.ex-badge.gaokao{background:rgba(214,69,48,.9);color:#fff;border:1px solid #ff9d8a}
.ex-badge.oly{background:rgba(247,201,72,.9);color:var(--ink);border:1px solid #fff}
.ex-title{font-size:16px;color:var(--yellow);font-weight:700}
.ex-stem{background:rgba(0,0,0,.15);border-left:4px solid var(--yellow);padding:10px 14px;border-radius:0 8px 8px 0;font-size:14px;line-height:1.7;color:var(--chalk);margin-bottom:12px}
.ex-sec-title{font-size:13.5px;font-weight:700;margin:10px 0 4px;display:flex;align-items:center;gap:6px}
.ex-model{background:rgba(88,166,255,.08);border:1.2px dashed rgba(88,166,255,.4);border-radius:8px;padding:10px 14px;font-size:13.5px;line-height:1.65;color:#cfe2ff;margin-bottom:10px}
.ex-steps{display:grid;gap:8px;list-style:none;counter-reset:ex-st;padding:0;margin:8px 0 10px}
.ex-steps li{display:flex;gap:10px;align-items:flex-start;font-size:13.5px;line-height:1.65;color:var(--chalk);background:rgba(0,0,0,.12);padding:8px 12px;border-radius:6px;border:1px solid rgba(242,239,226,.15)}
.ex-steps li::before{counter-increment:ex-st;content:counter(ex-st);flex:none;width:22px;height:22px;border-radius:50%;background:var(--yellow);color:var(--ink);font-weight:900;display:grid;place-items:center;font-size:12px}
.ex-summary{background:rgba(247,201,72,.08);border:1.2px solid rgba(247,201,72,.35);border-radius:8px;padding:10px 14px;font-size:13.5px;line-height:1.6;color:#fff2b2}

/* ---------- 实验探究与误差分析深度专栏 ---------- */
.exp-panel{background:#fff;border:2px solid var(--ink);border-radius:10px;padding:18px 22px;box-shadow:var(--hard)}
.exp-head{display:flex;align-items:center;gap:12px;margin-bottom:12px;border-bottom:2px dashed rgba(15,55,46,.2);padding-bottom:10px}
.exp-badge{background:var(--red);color:#fff;font-size:12px;font-weight:800;padding:3px 10px;border-radius:999px;letter-spacing:1px}
.exp-title{font-size:18px;margin:0;color:var(--ink)}
.exp-principle{font-size:14px;line-height:1.7;color:var(--ink);background:rgba(15,55,46,.05);padding:10px 14px;border-radius:8px;margin:0 0 14px;border-left:4px solid var(--ink)}
.exp-row{display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin-bottom:14px;font-size:13px}
.exp-tag-label{font-weight:700;color:var(--ink2)}
.exp-block{margin-top:14px;background:var(--paper2);padding:14px 16px;border-radius:8px;border:1.5px solid rgba(15,55,46,.15)}
.exp-sub-title{font-size:14.5px;font-weight:800;color:var(--ink);margin-bottom:10px;display:flex;align-items:center;gap:6px}
.exp-list{margin:0;padding-left:22px;font-size:13.5px;line-height:1.8;color:var(--ink)}
.exp-list li{margin-bottom:6px}
.exp-list.error-list{list-style-type:square;color:#7f1d1d}
.exp-list.error-list li{margin-bottom:6px}

/* ---------- 交互实验面板 ---------- */
.demo-sec{padding-top:0}
.demo{background:var(--paper2);border:2px solid var(--ink);border-radius:10px;box-shadow:var(--hard);padding:16px;position:relative}
.demo .demo-title{display:flex;justify-content:space-between;align-items:center;border-bottom:2px dashed rgba(15,55,46,.3);padding-bottom:8px;margin-bottom:10px;font-size:14.5px;font-weight:800;gap:10px;flex-wrap:wrap}
.demo .demo-title .btns{display:flex;gap:8px}
.demo .demo-desc{font-size:13px;color:var(--ink2);margin:-2px 0 10px}
.wstage{width:100%;display:block;touch-action:none}
.wstage text{user-select:none;-webkit-user-select:none;pointer-events:none}
.wstage .grabbable{cursor:grab;pointer-events:auto}
.wstage.dragging .grabbable{cursor:grabbing}
.wctl{display:flex;flex-wrap:wrap;gap:12px 22px;align-items:center;margin-top:12px;padding-top:12px;border-top:2px dashed rgba(15,55,46,.2)}
.wctl .wc{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:700;min-width:180px;flex:1}
.wctl .wc label{white-space:nowrap}
.wctl .wc output{font-family:'IBM Plex Mono';font-size:13px;background:var(--ink);color:#fff;border-radius:6px;padding:1px 8px;min-width:64px;text-align:center}
.wread{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-top:10px;font-size:13.5px}
.wread b{color:var(--red)}
.wcap{font-family:'Ma Shan Zheng';font-size:18px;color:var(--red);margin-top:10px;min-height:26px}
input[type=range]{width:100%;appearance:none;-webkit-appearance:none;height:12px;border-radius:6px;background:linear-gradient(90deg,var(--red),var(--yellow),var(--green));border:2px solid var(--ink);cursor:pointer;touch-action:pan-y}
input[type=range]::-webkit-slider-thumb{appearance:none;-webkit-appearance:none;width:26px;height:26px;border-radius:50%;background:#fff;border:3px solid var(--ink);box-shadow:2px 2px 0 rgba(15,55,46,.4);transition:.15s}
input[type=range]::-webkit-slider-thumb:hover{transform:scale(1.12)}
input[type=range]::-moz-range-thumb{width:24px;height:24px;border-radius:50%;background:#fff;border:3px solid var(--ink)}
.sgrid2{display:grid;grid-template-columns:1.15fr 1fr;gap:16px;align-items:stretch}
.sgrid2 .side{display:flex;flex-direction:column;gap:10px;font-size:13.5px}
.opt-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.opt-row .btn{padding:5px 14px;font-size:13px;box-shadow:2px 2px 0 var(--ink)}
.opt-row .btn.on{background:var(--yellow)}
.pdump{position:absolute;left:50%;transform:translateX(-50%);font-family:'IBM Plex Mono';font-size:12px;font-weight:600;background:var(--paper2);border:1.5px solid var(--ink);border-radius:5px;padding:0 6px;white-space:nowrap}
.hint-arrow{font-family:'Ma Shan Zheng';color:var(--red);font-size:18px;position:absolute;animation:bob 1.4s ease-in-out infinite;pointer-events:none}
@keyframes bob{50%{transform:translateY(6px)}}

/* ---------- 测验 ---------- */
.quiz-head{display:flex;align-items:center;gap:18px;flex-wrap:wrap;margin-bottom:22px}
.score-chip{font-family:'IBM Plex Mono';font-size:15px;font-weight:600;border:2px solid var(--ink);background:#fff;border-radius:999px;padding:6px 18px}
.score-chip b{color:var(--red)}
.q-card{margin-bottom:16px;padding:16px 18px}
.q-top{display:flex;gap:10px;align-items:center;margin-bottom:6px}
.q-no{font-family:'IBM Plex Mono';font-weight:600;background:var(--ink);color:#fff;border-radius:6px;padding:1px 9px;font-size:13px}
.q-tag{font-size:12px;color:var(--red);border:1.5px solid var(--red);border-radius:999px;padding:1px 10px}
.q-stem{font-weight:700;font-size:15px;margin-bottom:12px}
.opts{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.opt{text-align:left;border:2px solid rgba(15,55,46,.4);background:#fff;border-radius:8px;padding:9px 14px;font-family:inherit;font-size:14px;cursor:pointer;transition:.15s}
.opt:hover:not(:disabled){border-color:var(--ink);transform:translateX(3px)}
.opt.correct{background:#e3f4e9;border-color:var(--green);font-weight:700}
.opt.wrong{background:#fdeaea;border-color:var(--red)}
.opt:disabled{cursor:default}
.q-exp{display:none;margin-top:12px;border-left:4px solid var(--yellow);background:rgba(247,201,72,.15);padding:10px 14px;font-size:13.5px;border-radius:0 8px 8px 0}
.q-exp.show{display:block;animation:rowIn .5s}
@keyframes rowIn{from{background:var(--yellow)}}
.quiz-final{text-align:center;margin-top:20px}

/* ---------- 计算器（通用） ---------- */
.calc-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:10px 0}
.calc-grid label{font-size:12px;font-weight:700;display:block;margin-bottom:4px}
.calc-grid input{width:100%;border:2px solid var(--ink);border-radius:8px;padding:8px 6px;font-family:'IBM Plex Mono';font-size:14px;background:#fff;text-align:center;transition:.2s}
.calc-grid input:focus{outline:none;box-shadow:0 0 0 3px rgba(247,201,72,.6)}
.calc-grid input.solved{background:#fdf3d0;border-color:var(--red);animation:pop .4s}
@keyframes pop{50%{transform:scale(1.06)}}
.calc-msg{min-height:20px;font-size:13px;color:var(--red);font-weight:700}

/* ---------- 页脚 & 前后翻页 ---------- */
footer{background:var(--ink);color:#cfd6f2;padding:30px 0;font-size:13px;margin-top:40px}
footer .wrap{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap;align-items:center}
footer b{color:var(--yellow);font-family:'ZCOOL QingKe HuangYou';font-size:18px;letter-spacing:2px}
footer a{color:#cfd6f2}
.pnav-sec{padding:30px 0 0}
.pn-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.pn-card{display:block;text-decoration:none;color:var(--ink);border:2px solid var(--ink);background:var(--paper2);border-radius:10px;padding:12px 16px;box-shadow:4px 4px 0 rgba(15,55,46,.12);transition:.2s}
.pn-card.next{text-align:right}
.pn-card:hover{transform:translateY(-3px)}
.pn-card small{font-size:12px;color:var(--ink2)}
.pn-card b{font-size:16px}

/* ---------- 首页 ---------- */
.index-hero{padding:64px 0 40px;position:relative;overflow:hidden}
.index-hero h1{font-size:clamp(52px,9vw,110px);line-height:.95}
.index-hero h1 span{display:inline-block;transition:transform .3s}
.index-hero h1 span:hover{transform:translateY(-8px) rotate(-3deg)}
.index-hero .lede{font-size:16px;color:var(--ink2);max-width:58ch;margin-top:10px}
.search-row{display:flex;gap:12px;flex-wrap:wrap;align-items:center;margin:26px 0 8px}
.search-box{flex:1;min-width:240px;max-width:520px;position:relative}
.search-box input{width:100%;border:2px solid var(--ink);border-radius:10px;padding:11px 14px 11px 40px;font-size:15px;font-family:inherit;background:#fff;box-shadow:3px 3px 0 rgba(15,55,46,.14)}
.search-box input:focus{outline:none;box-shadow:0 0 0 3px rgba(247,201,72,.6)}
.search-box::before{content:'🔍';position:absolute;left:12px;top:50%;transform:translateY(-50%);font-size:16px}
.filters{display:flex;gap:8px;flex-wrap:wrap}
.fbtn{border:2px solid var(--ink);background:#fff;border-radius:999px;padding:7px 16px;font-size:13.5px;font-weight:800;cursor:pointer;transition:.15s;color:var(--ink)}
.fbtn:hover{transform:translateY(-2px)}
.fbtn.on{background:var(--ink);color:var(--yellow)}

/* ---------- 五大学科领域分类标签 ---------- */
.domain-filters{display:flex;gap:8px;flex-wrap:wrap;margin:12px 0 6px}
.dbtn{border:2px solid var(--ink);background:#fff;border-radius:8px;padding:6px 14px;font-size:13px;font-weight:700;cursor:pointer;transition:.15s;color:var(--ink);box-shadow:2px 2px 0 rgba(15,55,46,.1)}
.dbtn:hover{transform:translateY(-2px);box-shadow:3px 3px 0 var(--ink)}
.dbtn.on{background:var(--red);color:#fff;border-color:var(--ink);box-shadow:3px 3px 0 var(--ink)}

/* ---------- 物理常量与单位速查抽屉 ---------- */
.phys-drawer-mask{position:fixed;top:0;left:0;right:0;bottom:0;background:rgba(10,14,30,.72);backdrop-filter:blur(4px);z-index:999;display:flex;justify-content:flex-end;opacity:0;pointer-events:none;transition:.25s ease}
.phys-drawer-mask.open{opacity:1;pointer-events:auto}
.phys-drawer{width:min(580px,100vw);height:100%;height:100dvh;background:var(--paper);box-shadow:-6px 0 24px rgba(0,0,0,.35);border-left:2.5px solid var(--ink);display:flex;flex-direction:column;transform:translateX(100%);transition:.28s cubic-bezier(.16,1,.3,1);padding-bottom:env(safe-area-inset-bottom,0px)}
.phys-drawer-mask.open .phys-drawer{transform:translateX(0)}
.drawer-header{display:flex;align-items:center;justify-content:space-between;padding:12px 16px;padding-top:max(12px,calc(12px + env(safe-area-inset-top,0px)));border-bottom:2px solid var(--ink);background:var(--paper2)}
.drawer-tabs{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;-webkit-overflow-scrolling:touch}
.drawer-tabs::-webkit-scrollbar{display:none}
.dtab{border:1.8px solid var(--ink);background:#fff;border-radius:6px;padding:6px 12px;font-size:12.5px;font-weight:700;cursor:pointer;transition:.15s;color:var(--ink);white-space:nowrap;flex-shrink:0}
.dtab.on{background:var(--ink);color:var(--yellow)}
.drawer-close{width:32px;height:32px;border:2px solid var(--ink);border-radius:6px;background:#fff;font-size:16px;font-weight:900;cursor:pointer;display:grid;place-items:center;box-shadow:2px 2px 0 var(--ink);flex-shrink:0}
.drawer-close:hover{background:var(--red);color:#fff}
.drawer-body{flex:1;overflow-y:auto;-webkit-overflow-scrolling:touch;padding:16px}
.const-table{width:100%;border-collapse:collapse;font-size:13px}
.const-table th{background:var(--ink);color:var(--yellow);padding:8px 10px;text-align:left;font-family:'IBM Plex Mono','Noto Sans SC'}
.const-table td{padding:8px 10px;border-bottom:1px solid rgba(15,55,46,.15)}
.const-table tr:hover{background:rgba(247,201,72,.15)}
.const-copy{cursor:pointer;border:1px solid var(--ink);background:#fff;border-radius:4px;padding:2px 8px;font-size:11.5px;margin-left:6px;font-family:inherit}
.const-copy:active{background:var(--yellow)}
.conv-card{background:#fff;border:2px solid var(--ink);border-radius:10px;box-shadow:3px 3px 0 rgba(15,55,46,.12);padding:14px 16px;margin-bottom:16px}
.conv-title{font-size:14.5px;font-weight:800;color:var(--ink);margin-bottom:10px;display:flex;align-items:center;gap:6px}
.conv-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.conv-box{flex:1;min-width:120px}
.conv-box label{font-size:12px;color:var(--ink2);display:block;margin-bottom:3px;font-weight:700}
.conv-box input{width:100%;border:1.8px solid var(--ink);border-radius:6px;padding:6px 10px;font-family:'IBM Plex Mono';font-size:14px;font-weight:600;box-sizing:border-box}
.conv-box input:focus{outline:none;border-color:var(--red);background:#fffef5}
.conv-eq{font-size:18px;font-weight:900;color:var(--red);padding-top:14px}
.conv-presets{display:flex;gap:6px;flex-wrap:wrap;margin-top:8px}
.cpreset{border:1px dashed var(--ink);background:rgba(15,55,46,.05);border-radius:4px;padding:2px 8px;font-size:11.5px;cursor:pointer}
.cpreset:hover{background:var(--yellow)}

/* ---------- 秒杀二级结论速查 ---------- */
.sec-search-box{margin-bottom:12px;position:relative}
.sec-search-box input{width:100%;border:2px solid var(--ink);border-radius:8px;padding:9px 12px 9px 34px;font-size:14px;background:#fff;box-sizing:border-box}
.sec-search-box::before{content:'🔍';position:absolute;left:10px;top:50%;transform:translateY(-50%);font-size:14px}
.sec-cat-row{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;-webkit-overflow-scrolling:touch;margin-bottom:14px;padding-bottom:2px}
.sec-cat-row::-webkit-scrollbar{display:none}
.scat-btn{border:1.6px solid var(--ink);background:#fff;border-radius:999px;padding:4px 12px;font-size:12px;font-weight:700;cursor:pointer;white-space:nowrap;transition:.15s;flex-shrink:0}
.scat-btn.on{background:var(--red);color:#fff;border-color:var(--red)}
.sec-card{background:#fff;border:2px solid var(--ink);border-radius:10px;padding:14px 16px;margin-bottom:14px;box-shadow:3px 3px 0 rgba(15,55,46,.12);transition:.15s}
.sec-card:hover{transform:translateY(-2px);box-shadow:4px 4px 0 var(--ink)}
.sec-card-top{display:flex;align-items:center;justify-content:space-between;gap:8px;margin-bottom:8px;flex-wrap:wrap}
.sec-card-title{font-size:15px;font-weight:800;color:var(--ink);display:flex;align-items:center;gap:6px}
.sec-card-badge{font-size:11px;background:var(--paper2);color:var(--ink);border:1.2px solid var(--ink);border-radius:4px;padding:1px 6px;font-weight:700}
.sec-formula-box{background:rgba(15,55,46,.05);border-left:4px solid var(--red);border-radius:0 6px 6px 0;padding:8px 12px;margin:8px 0;font-family:'IBM Plex Mono','Noto Sans SC';font-size:13.5px;font-weight:700;color:var(--ink);overflow-x:auto;-webkit-overflow-scrolling:touch}
.sec-cond{font-size:12.5px;color:var(--ink2);line-height:1.6;margin:6px 0}
.sec-cond b{color:var(--ink)}
.sec-memo{font-size:12.5px;background:#fef9e7;border:1px dashed #e6b800;border-radius:6px;padding:6px 10px;color:#7a5a00;line-height:1.6;margin-top:6px}
.sec-copy-btn{border:1px solid var(--ink);background:#fff;border-radius:4px;padding:2px 8px;font-size:11.5px;cursor:pointer;font-weight:600}
.sec-copy-btn:active{background:var(--yellow)}

.float-tool-btn{position:fixed;right:calc(18px + env(safe-area-inset-right,0px));bottom:calc(22px + env(safe-area-inset-bottom,0px));width:48px;height:48px;border-radius:50%;background:var(--yellow);color:var(--ink);border:2.5px solid var(--ink);box-shadow:4px 4px 0 var(--ink);font-size:22px;cursor:pointer;z-index:88;display:grid;place-items:center;transition:.2s}
.float-tool-btn:hover{transform:translate(-2px,-2px) scale(1.05);box-shadow:6px 6px 0 var(--ink)}
.float-tool-btn:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink)}
.nav-tool-btn{background:var(--yellow);color:var(--ink);border:2px solid var(--ink);box-shadow:2px 2px 0 rgba(15,55,46,.25);border-radius:6px;font-size:12.5px;font-weight:800;cursor:pointer;padding:4px 10px;display:inline-flex;align-items:center;gap:4px}
.nav-tool-btn:hover{background:#ffe082}

.mod-zone{margin:34px 0}
.mod-card{position:relative;border:2px solid var(--ink);border-radius:12px;background:var(--paper2);box-shadow:var(--hard);padding:18px 20px;margin-bottom:26px;overflow:hidden}
.mod-card::after{content:attr(data-no);position:absolute;right:6px;top:-26px;font-family:'ZCOOL QingKe HuangYou';font-size:110px;color:rgba(15,55,46,.06);pointer-events:none}
.mod-head{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:12px}
.mod-emoji{width:46px;height:46px;border:2px solid var(--ink);border-radius:10px;display:grid;place-items:center;font-size:24px;background:#fff}
.mod-head h3{font-size:26px}
.mod-head .des{font-size:13px;color:var(--ink2)}
.mod-head .cnt{margin-left:auto;font-family:'IBM Plex Mono';font-size:12.5px;color:var(--ink2)}
.topic-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:12px}
.topic{display:flex;gap:10px;align-items:center;border:2px solid var(--ink);background:#fff;border-radius:9px;padding:9px 12px;text-decoration:none;color:var(--ink);box-shadow:3px 3px 0 rgba(15,55,46,.14);transition:.18s;font-size:14px;font-weight:700}
.topic:hover{transform:translateY(-3px);background:var(--yellow)}
.topic .te{font-size:19px}
.topic .tk{margin-left:auto;font-family:'IBM Plex Mono';font-size:10.5px;color:var(--ink2);font-weight:600;background:rgba(15,55,46,.08);border-radius:5px;padding:1px 7px;white-space:nowrap}
.school-tab{display:flex;gap:10px;margin:0 0 18px;flex-wrap:wrap}
.school-tab .stab{border:2px solid var(--ink);background:#fff;border-radius:10px;padding:10px 18px;cursor:pointer;display:flex;gap:10px;align-items:center;box-shadow:3px 3px 0 rgba(15,55,46,.14);transition:.18s;font-family:inherit}
.school-tab .stab:hover{transform:translateY(-2px)}
.school-tab .stab.on{background:var(--ink);color:var(--yellow)}
.school-tab .stab b{font-size:16px}
.school-tab .stab small{font-size:11.5px;opacity:.75}
.count-note{font-size:13px;color:var(--ink2);text-align:center;padding:20px 0}
.ios-hint{display:none;margin:0 0 22px;border:2px dashed var(--green);background:#eaf6ef;border-radius:10px;padding:12px 16px;font-size:13.5px;color:#245e46}
.ios-hint.show{display:block}

/* ---------- 随堂测验学习进度与徽章 ---------- */
.q-badge{font-size:11px;padding:1px 6px;border-radius:4px;font-family:'IBM Plex Mono','Noto Sans SC';font-weight:700;white-space:nowrap;margin-left:4px}
.q-badge.perfect{background:#e8f5e9;color:#2e7d32;border:1px solid #a5d6a7}
.q-badge.done{background:#fff8e1;color:#f57f17;border:1px solid #ffe082}
.chip.prog-chip{background:#e8f5e9;color:#1b5e20;border-color:#2e7d32;display:none}

/* ---------- PWA 更新提示栏 ---------- */
.pwa-update-bar{position:fixed;bottom:calc(20px + env(safe-area-inset-bottom,0px));left:50%;transform:translateX(-50%);background:var(--ink);color:#fff;border:2px solid var(--yellow);border-radius:999px;padding:8px 18px;display:flex;align-items:center;gap:12px;box-shadow:0 8px 24px rgba(0,0,0,.35);z-index:9999;font-size:13.5px;animation:pop .3s ease}
.pwa-update-bar button#pwaReloadBtn{background:var(--yellow);color:var(--ink);border:none;border-radius:999px;padding:4px 14px;font-size:12.5px;font-weight:800;cursor:pointer;transition:.15s}
.pwa-update-bar button#pwaReloadBtn:hover{background:#fff}
.pwa-update-close{background:transparent;border:none;color:#aaa;font-size:14px;cursor:pointer;padding:0 4px}
.pwa-update-close:hover{color:#fff}

/* ---------- 响应式与移动端专属优化 ---------- */
@media (max-width:920px){
  .grid2,.grid3,.pn-grid{grid-template-columns:1fr}
  .sec-note{margin-left:0}
  .calc-grid{grid-template-columns:repeat(2,1fr)}
  .sgrid2{grid-template-columns:1fr}
}
@media (max-width:680px){
  .nav-links{display:none}
  .opts{grid-template-columns:1fr}
}
@media (max-width:640px){
  input[type="text"],input[type="number"],input[type="search"]{font-size:16px!important}
}