/* ===== 分析化学实验数据计算平台 · 浅色主题 ===== */
:root{
  --bg:#f4f6fb;
  --panel:#ffffff;
  --ink:#1f2937;
  --ink-soft:#4b5563;
  --muted:#6b7280;
  --line:#e5e7eb;
  --line-strong:#d1d5db;
  --brand:#2563eb;
  --brand-soft:#eff4ff;
  --brand-ink:#1d4ed8;
  --accent:#0d9488;
  --warn:#b45309;
  --warn-bg:#fffbeb;
  --good:#15803d;
  --good-bg:#f0fdf4;
  --bad:#b91c1c;
  --bad-bg:#fef2f2;
  --chip:#eef2f7;
  --shadow:0 1px 2px rgba(16,24,40,.06),0 1px 3px rgba(16,24,40,.08);
  --radius:12px;
  --mono:"SFMono-Regular",ui-monospace,Menlo,Consolas,"Liberation Mono",monospace;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;height:100%}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--ink);font-size:14px;line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
.app{display:flex;min-height:100vh}

/* ---------- Sidebar ---------- */
.sidebar{
  width:280px;flex-shrink:0;background:var(--panel);border-right:1px solid var(--line);
  display:flex;flex-direction:column;position:sticky;top:0;height:100vh;overflow:hidden;
}
.brand{display:flex;align-items:center;gap:12px;padding:18px 18px 14px}
.brand-logo{
  width:40px;height:40px;border-radius:10px;background:linear-gradient(135deg,#2563eb,#0d9488);
  display:flex;align-items:center;justify-content:center;font-size:22px;color:#fff;flex-shrink:0;
}
.brand-title{font-weight:700;font-size:15px;color:var(--ink)}
.brand-sub{font-size:12px;color:var(--muted)}
.search-wrap{padding:0 14px 10px}
.search{
  width:100%;padding:9px 12px;border:1px solid var(--line-strong);border-radius:8px;
  font-size:13px;background:var(--bg);color:var(--ink);outline:none;transition:.15s;
}
.search:focus{border-color:var(--brand);background:#fff;box-shadow:0 0 0 3px var(--brand-soft)}
.nav{flex:1;overflow-y:auto;padding:4px 8px 12px}
.nav-group{margin-top:8px}
.nav-group-title{font-size:11px;font-weight:600;color:var(--muted);padding:8px 10px 4px;letter-spacing:.04em}
.nav-item{
  display:flex;align-items:center;gap:10px;padding:9px 10px;border-radius:8px;cursor:pointer;
  color:var(--ink-soft);font-size:13px;transition:.12s;border:1px solid transparent;
}
.nav-item:hover{background:var(--chip)}
.nav-item.active{background:var(--brand-soft);color:var(--brand-ink);font-weight:600;border-color:#dbe6ff}
.nav-idx{
  width:22px;height:22px;border-radius:6px;background:var(--chip);color:var(--muted);
  display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:700;flex-shrink:0;
}
.nav-item.active .nav-idx{background:var(--brand);color:#fff}
.nav-title{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.sidebar-foot{padding:10px 16px;border-top:1px solid var(--line);font-size:11px;color:var(--muted)}

/* ---------- Main ---------- */
.main{flex:1;min-width:0;display:flex;flex-direction:column}
.topbar{
  height:54px;display:flex;align-items:center;gap:12px;padding:0 22px;
  background:var(--panel);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20;
}
.menu-toggle{display:none;background:none;border:none;font-size:20px;cursor:pointer;color:var(--ink)}
.crumb{font-weight:600;font-size:14px;color:var(--ink);flex:1}
.topbar-actions{display:flex;gap:8px}
.btn{
  padding:7px 14px;border-radius:8px;font-size:13px;cursor:pointer;border:1px solid var(--line-strong);
  background:var(--panel);color:var(--ink-soft);transition:.15s;font-weight:500;
}
.btn:hover{background:var(--chip)}
.btn.primary{background:var(--brand);color:#fff;border-color:var(--brand)}
.btn.primary:hover{background:var(--brand-ink)}
.btn.ghost{background:transparent}
.content{padding:24px 28px 60px;max-width:1080px;width:100%}

/* ---------- Experiment header ---------- */
.exp-head{margin-bottom:18px}
.exp-cat{
  display:inline-block;font-size:11px;font-weight:600;color:var(--brand-ink);background:var(--brand-soft);
  padding:3px 10px;border-radius:20px;margin-bottom:10px;
}
.exp-title{font-size:22px;font-weight:700;color:var(--ink);margin:0 0 6px;line-height:1.35}
.exp-no{font-size:12px;color:var(--muted);font-weight:500}

/* ---------- Cards ---------- */
.card{
  background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);
  padding:18px 20px;margin-bottom:16px;box-shadow:var(--shadow);
}
.card h3{margin:0 0 10px;font-size:15px;font-weight:700;color:var(--ink);display:flex;align-items:center;gap:8px}
.card h3 .tag{font-size:11px;font-weight:600;color:var(--accent);background:#e6f7f5;padding:2px 8px;border-radius:6px}
.principle{color:var(--ink-soft);font-size:13.5px;line-height:1.75}
.reactions{margin-top:10px;display:flex;flex-direction:column;gap:6px}
.reaction{
  font-family:var(--mono);font-size:12.5px;background:var(--bg);border:1px solid var(--line);
  border-radius:8px;padding:8px 12px;color:var(--ink);overflow-x:auto;
}
.formula-box{
  margin-top:12px;background:var(--brand-soft);border:1px solid #dbe6ff;border-radius:8px;padding:10px 14px;
}
.formula-box .flabel{font-size:11px;font-weight:600;color:var(--brand-ink);margin-bottom:4px}
.formula-box code{font-family:var(--mono);font-size:13px;color:var(--brand-ink);word-break:break-word}

/* ---------- Section ---------- */
.section{margin-bottom:18px}
.section-head{display:flex;align-items:center;gap:10px;margin-bottom:12px}
.section-badge{
  width:26px;height:26px;border-radius:7px;background:var(--brand);color:#fff;font-size:12px;font-weight:700;
  display:flex;align-items:center;justify-content:center;flex-shrink:0;
}
.section-title{font-size:15px;font-weight:700;color:var(--ink)}
.section-desc{font-size:12.5px;color:var(--muted);margin:-4px 0 12px 36px}

/* ---------- Inputs ---------- */
.field{margin-bottom:12px}
.field-label{display:block;font-size:12.5px;font-weight:600;color:var(--ink-soft);margin-bottom:5px}
.field-label .unit{font-weight:400;color:var(--muted);margin-left:4px}
.input{
  width:100%;padding:9px 12px;border:1px solid var(--line-strong);border-radius:8px;font-size:13.5px;
  font-family:var(--mono);color:var(--ink);background:#fff;outline:none;transition:.15s;
}
.input:focus{border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-soft)}
.input::placeholder{color:#aab2bd}
.grid{display:grid;gap:12px}
.grid-2{grid-template-columns:1fr 1fr}
.grid-3{grid-template-columns:1fr 1fr 1fr}
.grid-4{grid-template-columns:repeat(4,1fr)}
@media(max-width:760px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}}

/* trial table */
.trial-table{width:100%;border-collapse:collapse;font-size:12.5px;margin-bottom:4px}
.trial-table th,.trial-table td{border:1px solid var(--line);padding:6px 8px;text-align:center}
.trial-table th{background:var(--chip);color:var(--ink-soft);font-weight:600;font-size:12px}
.trial-table .trial-input{width:100%;border:none;text-align:center;font-family:var(--mono);font-size:13px;padding:4px;outline:none;background:transparent}
.trial-table .trial-input:focus{background:var(--brand-soft)}
.trial-table .row-label{text-align:left;font-weight:600;color:var(--ink-soft);white-space:nowrap;background:#fafbfc}

.calc-row{display:flex;gap:10px;align-items:center;margin-top:14px;flex-wrap:wrap}
.hint{font-size:11.5px;color:var(--muted)}

/* ---------- Results ---------- */
.results{margin-top:14px;animation:fade .25s ease}
@keyframes fade{from{opacity:0;transform:translateY(4px)}to{opacity:1;transform:none}}
.result-table{width:100%;border-collapse:collapse;font-size:13px;margin-bottom:10px}
.result-table th,.result-table td{border:1px solid var(--line);padding:8px 10px;text-align:center}
.result-table th{background:var(--chip);color:var(--ink-soft);font-weight:600}
.result-table td.val{font-family:var(--mono);font-weight:600;color:var(--ink)}
.result-table tr.summary td{background:var(--good-bg);font-weight:700;color:var(--good)}
.result-table tr.summary td.val{color:var(--good)}

.kpis{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:12px}
.kpi{
  flex:1;min-width:140px;background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:12px 14px;
}
.kpi .k-label{font-size:11.5px;color:var(--muted);margin-bottom:4px}
.kpi .k-val{font-size:18px;font-weight:700;color:var(--ink);font-family:var(--mono)}
.kpi .k-val.good{color:var(--good)}
.kpi .k-val.warn{color:var(--warn)}
.kpi .k-val.bad{color:var(--bad)}
.kpi .k-unit{font-size:12px;color:var(--muted);font-weight:400;margin-left:3px}

.conclusion{
  border-radius:10px;padding:12px 16px;font-size:13px;margin-top:6px;border:1px solid;
  display:flex;gap:10px;align-items:flex-start;
}
.conclusion.good{background:var(--good-bg);border-color:#bbf7d0;color:var(--good)}
.conclusion.warn{background:var(--warn-bg);border-color:#fde68a;color:var(--warn)}
.conclusion.bad{background:var(--bad-bg);border-color:#fecaca;color:var(--bad)}
.conclusion .ico{font-size:16px;flex-shrink:0;margin-top:1px}

.notes{margin-top:10px;padding-left:2px}
.notes li{font-size:12px;color:var(--muted);margin-bottom:3px}

/* ---------- Reference ---------- */
.ref-table{width:100%;border-collapse:collapse;font-size:12.5px}
.ref-table th,.ref-table td{border:1px solid var(--line);padding:7px 10px;text-align:left}
.ref-table th{background:var(--chip);color:var(--ink-soft);font-weight:600}
.ref-table td.v{font-family:var(--mono);color:var(--ink)}
.ref-note{font-size:12px;color:var(--muted);margin-top:8px;line-height:1.6}
.ref-sources{margin-top:8px;font-size:11.5px;color:var(--muted)}
.ref-sources a{color:var(--brand);text-decoration:none;word-break:break-all}
.ref-sources a:hover{text-decoration:underline}

/* ---------- Welcome ---------- */
.welcome{max-width:720px}
.welcome h1{font-size:24px;margin:0 0 6px}
.welcome p{color:var(--ink-soft);line-height:1.8}
.welcome .feats{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:18px}
@media(max-width:760px){.welcome .feats{grid-template-columns:1fr}}
.feat{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:14px 16px}
.feat .ft{font-weight:700;color:var(--ink);margin-bottom:3px;font-size:13.5px}
.feat .fd{font-size:12.5px;color:var(--muted);line-height:1.6}

/* ---------- Toast ---------- */
.toast{
  position:fixed;bottom:24px;left:50%;transform:translateX(-50%) translateY(20px);
  background:var(--ink);color:#fff;padding:10px 18px;border-radius:8px;font-size:13px;
  opacity:0;pointer-events:none;transition:.25s;z-index:100;box-shadow:0 8px 24px rgba(0,0,0,.2);
}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* ---------- Mobile ---------- */
@media(max-width:900px){
  .sidebar{position:fixed;left:0;top:0;z-index:50;transform:translateX(-100%);transition:.25s;box-shadow:0 0 40px rgba(0,0,0,.15)}
  .sidebar.open{transform:none}
  .menu-toggle{display:block}
  .content{padding:18px 16px 50px}
}
.overlay{display:none;position:fixed;inset:0;background:rgba(0,0,0,.3);z-index:40}
.overlay.show{display:block}
@media(max-width:900px){.overlay.show{display:block}}