/* ============================================
   Химия ЕГЭ · Общие стили для всех страниц
   ============================================ */

/* ---------- ТЕМА: СВЕТЛАЯ ---------- */
:root{
  --lav:#E5D4F0;
  --lav2:#D9BCEC;
  --lav3:#C99FE8;
  --violet:#A855F7;
  --violet-dark:#7c3aed;
  --dark:#1a0b2e;
  --mid:#4a1d7a;
  --bg:#faf7fc;
  --card:#ffffff;
  --line:#e3d9ee;
  --nav-bg:rgba(255,255,255,.96);
  --rx-bg:#faf7fc;
  --cta-bg:#1a0b2e;
  --cta-tx:#ffffff;
  --red:#c0392b;
  --green:#059669;
  --amber:#d97706;
  --warn-bg:#fef2f2; --warn-tx:#7f1d1d;
  --rule-bg:#eff6ff; --rule-tx:#1e3a8a;
  --ex-bg:#f0fdf4;   --ex-tx:#14532d;
  --att-bg:#fffbeb;  --att-tx:#78350f;
  --shadow-sm:0 2px 12px rgba(26,11,46,.06);
  --shadow-md:0 16px 40px rgba(168,85,247,.15);
}

/* ---------- ТЕМА: ТЁМНАЯ ---------- */
[data-theme="dark"]{
  --lav:#2a1748;
  --lav2:#3a2360;
  --lav3:#4a2d80;
  --violet:#A855F7;
  --violet-dark:#c99fe8;
  --dark:#f0e8fa;
  --mid:#c4a8e8;
  --bg:#150826;
  --card:#1f0f38;
  --line:#2d1a4a;
  --nav-bg:rgba(31,15,56,.96);
  --rx-bg:#1a0d2e;
  --cta-bg:#251146;
  --cta-tx:#ffffff;
  --red:#f87171;
  --green:#34d399;
  --amber:#fbbf24;
  --warn-bg:#3b0f14; --warn-tx:#fecaca;
  --rule-bg:#0f1e3b; --rule-tx:#bfdbfe;
  --ex-bg:#0a2a1a;   --ex-tx:#bbf7d0;
  --att-bg:#3b260a;  --att-tx:#fde68a;
  --shadow-sm:0 2px 12px rgba(0,0,0,.3);
  --shadow-md:0 16px 40px rgba(168,85,247,.25);
}

/* ---------- БАЗА ---------- */
*{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;}
body{
  font-family:Georgia,"PT Serif",serif;
  background:var(--bg);
  color:var(--dark);
  font-size:16px;
  line-height:1.6;
  transition:background .3s, color .3s;
}
a{color:inherit;}

/* ---------- PROGRESS BAR ---------- */
.progress-bar{
  position:fixed;top:0;left:0;height:3px;width:0;
  background:linear-gradient(90deg,var(--violet),var(--violet-dark));
  z-index:200;
  transition:width .1s ease;
}

/* ---------- NAV ---------- */
.nav{
  position:sticky;top:0;z-index:100;
  background:var(--nav-bg);
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
  box-shadow:var(--shadow-sm);
  transition:background .3s, border-color .3s;
}
.nav-inner{
  width:100%;
  padding:12px 32px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
  flex-wrap:nowrap;
}
.nav-logo{
  display:flex;align-items:center;gap:10px;
  font-size:16px;font-weight:800;letter-spacing:-.3px;
  color:var(--dark);text-decoration:none;
  flex-shrink:0;
}
.nav-logo .mark{
  width:36px;height:36px;border-radius:10px;
  background:var(--violet);color:#fff;
  display:flex;align-items:center;justify-content:center;
  font-size:14px;font-weight:800;
  flex-shrink:0;
}
.nav-links{
  display:flex;
  gap:4px;
  align-items:center;
  justify-content:center;
  flex:1;
  min-width:0;
  flex-wrap:nowrap;
}
.nav-links a{
  color:var(--mid);text-decoration:none;
  font-size:13.5px;font-weight:700;
  padding:8px 12px;border-radius:8px;
  transition:background .15s, color .15s;
  white-space:nowrap;
}
.nav-links a:hover{background:var(--lav);color:var(--dark);}
.nav-links a.active{background:var(--lav);color:var(--violet-dark);}
.nav-links a.cta{background:var(--violet);color:#fff;}
.nav-links a.cta:hover{background:var(--violet-dark);}

.nav-actions{
  display:flex;align-items:center;gap:8px;
  flex-shrink:0;
}
.search-wrap{position:relative;}
.search-input{
  width:150px;height:36px;
  padding:0 12px 0 32px;
  border:1px solid var(--line);border-radius:9px;
  background:var(--bg);color:var(--dark);
  font-family:inherit;font-size:13.5px;
  transition:width .2s, border-color .2s, background .3s;
}
.search-input:focus{
  outline:none;border-color:var(--violet);
  width:200px;
}
.search-wrap::before{
  content:"🔍";position:absolute;left:10px;top:50%;
  transform:translateY(-50%);font-size:12px;opacity:.6;
  pointer-events:none;
}
.icon-btn{
  background:var(--lav);border:none;cursor:pointer;
  width:36px;height:36px;border-radius:9px;
  font-size:15px;
  display:grid;place-items:center;
  color:var(--violet-dark);
  transition:background .15s, transform .15s;
}
.icon-btn:hover{background:var(--lav2);transform:scale(1.05);}
/* ---------- HERO ---------- */
.hero{
  max-width:1200px;margin:0 auto;
  padding:72px 24px 48px;
  text-align:center;
}
.hero .badge{
  display:inline-block;
  background:var(--lav);
  color:var(--violet-dark);
  font-size:12.5px;font-weight:800;
  letter-spacing:.6px;text-transform:uppercase;
  padding:6px 14px;border-radius:999px;
  margin-bottom:20px;
}
.hero h1{
  font-size:52px;font-weight:800;
  letter-spacing:-1.4px;line-height:1.1;
  margin-bottom:20px;
  max-width:900px;margin-left:auto;margin-right:auto;
}
.hero h1 .accent{color:var(--violet-dark);}
.hero .lead{
  font-size:19px;color:var(--mid);
  max-width:680px;margin:0 auto 32px;
  line-height:1.6;
}
.hero .buttons{
  display:flex;gap:12px;justify-content:center;flex-wrap:wrap;
}
.btn{
  display:inline-block;
  padding:15px 32px;
  border-radius:12px;
  font-size:16px;font-weight:800;
  text-decoration:none;
  transition:all .15s;
  font-family:inherit;
  border:none;cursor:pointer;
}
.btn-primary{
  background:var(--violet);color:#fff;
  box-shadow:0 4px 14px rgba(168,85,247,.35);
}
.btn-primary:hover{
  background:var(--violet-dark);
  transform:translateY(-2px);
  box-shadow:0 8px 24px rgba(168,85,247,.45);
}
.btn-secondary{
  background:var(--card);color:var(--dark);
  border:2px solid var(--line);
}
.btn-secondary:hover{
  border-color:var(--violet);color:var(--violet-dark);
}

.hero-stats{
  display:flex;justify-content:center;gap:48px;
  flex-wrap:wrap;margin-top:56px;
}
.hero-stat{text-align:center;}
.hero-stat .num{
  font-size:38px;font-weight:800;
  color:var(--violet-dark);letter-spacing:-1px;
  display:block;
}
.hero-stat .lbl{
  font-size:13.5px;color:var(--mid);
  margin-top:6px;font-style:italic;
}

/* ---------- SECTIONS ---------- */
.section{
  max-width:1200px;margin:0 auto;
  padding:64px 24px;
}
.section-head{
  text-align:center;margin-bottom:48px;
}
.section-head h2{
  font-size:34px;font-weight:800;
  letter-spacing:-.8px;margin-bottom:12px;
}
.section-head p{
  font-size:17px;color:var(--mid);
  max-width:640px;margin:0 auto;
  font-style:italic;
}

/* ---------- PART CARDS ---------- */
.parts{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(300px,1fr));
  gap:24px;
}
.part-card{
  display:block;
  background:var(--card);
  border:2px solid var(--line);
  border-radius:18px;
  padding:32px 28px;
  text-decoration:none;color:inherit;
  transition:all .2s;
  position:relative;overflow:hidden;
}
.part-card::before{
  content:"";
  position:absolute;left:0;top:0;right:0;height:6px;
  background:var(--violet);
}
.part-card:hover{
  border-color:var(--violet);
  transform:translateY(-4px);
  box-shadow:var(--shadow-md);
}
.part-icon{
  font-size:42px;display:block;margin-bottom:16px;
}
.part-card h3{
  font-size:22px;font-weight:800;
  letter-spacing:-.4px;margin-bottom:12px;
}
.part-card .desc{
  font-size:14.5px;color:var(--mid);
  line-height:1.55;margin-bottom:16px;
}
.part-card .meta{
  font-size:13px;font-weight:800;
  color:var(--violet-dark);letter-spacing:.3px;
}
.part-card .meta::after{content:" →";margin-left:4px;}

/* ---------- FEATURES ---------- */
.features{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(260px,1fr));
  gap:20px;
}
.feature{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:14px;
  padding:26px 24px;
  transition:background .3s, border-color .3s;
}
.feature .icon{
  font-size:28px;display:block;margin-bottom:12px;
}
.feature h4{
  font-size:16px;font-weight:800;
  margin-bottom:8px;
}
.feature p{
  font-size:14.5px;color:var(--mid);line-height:1.55;
}

/* ---------- PRICING ---------- */
.pricing{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(300px,1fr));
  gap:24px;
  max-width:900px;margin:0 auto;
  align-items:stretch;
}
.price-card{
  background:var(--card);
  border:2px solid var(--line);
  border-radius:20px;
  padding:36px 30px;
  display:flex;flex-direction:column;
  position:relative;
  transition:all .2s, background .3s, border-color .3s;
}
.price-card.featured{
  border-color:var(--violet);
  box-shadow:var(--shadow-md);
  transform:scale(1.02);
}
.price-badge{
  position:absolute;top:-14px;left:50%;
  transform:translateX(-50%);
  background:var(--violet);color:#fff;
  padding:5px 16px;border-radius:999px;
  font-size:11.5px;font-weight:800;
  letter-spacing:.6px;text-transform:uppercase;
  white-space:nowrap;
}
.price-name{
  font-size:14px;font-weight:800;
  color:var(--mid);text-transform:uppercase;
  letter-spacing:.8px;margin-bottom:16px;
}
.price-value{
  font-size:44px;font-weight:800;
  color:var(--dark);letter-spacing:-1.2px;
  line-height:1;margin-bottom:24px;
}
.price-value .cur{font-size:24px;margin-right:2px;}
.price-list{
  list-style:none;padding:0;margin-bottom:28px;
  flex:1;
}
.price-list li{
  font-size:14.5px;padding:8px 0 8px 28px;
  position:relative;line-height:1.5;
}
.price-list li::before{
  content:"✓";position:absolute;left:0;top:8px;
  color:#10b981;font-weight:800;
}
.price-list li.no{
  color:#9ca3af;text-decoration:line-through;
}
.price-list li.no::before{
  content:"—";color:#9ca3af;
}
.price-btn{
  display:block;text-align:center;
  padding:14px 20px;border-radius:10px;
  font-size:15px;font-weight:800;
  text-decoration:none;
  transition:all .15s;
}
.price-btn.primary{background:var(--violet);color:#fff;}
.price-btn.primary:hover{background:var(--violet-dark);}
.price-btn.secondary{
  background:var(--lav);color:var(--dark);
  border:1px solid var(--line);
}
.price-btn.secondary:hover{background:var(--lav2);}

/* ---------- STEPS ---------- */
.steps{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:24px;
  counter-reset:step;
}
.step{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:14px;
  padding:28px 24px;
  position:relative;
  counter-increment:step;
  transition:background .3s, border-color .3s;
}
.step::before{
  content:counter(step);
  position:absolute;top:-18px;left:24px;
  width:40px;height:40px;border-radius:50%;
  background:var(--violet);color:#fff;
  font-size:18px;font-weight:800;
  display:flex;align-items:center;justify-content:center;
}
.step h4{
  font-size:16px;font-weight:800;
  margin:16px 0 8px;
}
.step p{
  font-size:14.5px;color:var(--mid);line-height:1.55;
}

/* ---------- CTA BLOCK ---------- */
.cta-block{
  background:var(--cta-bg);
  color:var(--cta-tx);
  padding:72px 24px;
  text-align:center;
  transition:background .3s;
}
.cta-block h2{
  font-size:36px;font-weight:800;
  letter-spacing:-.8px;margin-bottom:16px;
}
.cta-block p{
  font-size:17px;color:rgba(255,255,255,.75);
  max-width:600px;margin:0 auto 32px;
}

/* ---------- FOOTER ---------- */
.footer{
  background:var(--card);
  border-top:1px solid var(--line);
  padding:40px 24px 32px;
  text-align:center;
  transition:background .3s, border-color .3s;
}
.footer-inner{max-width:1200px;margin:0 auto;}
.footer-logo{
  font-size:18px;font-weight:800;
  color:var(--dark);margin-bottom:12px;
  display:flex;align-items:center;gap:10px;justify-content:center;
}
.footer-logo .mark{
  width:32px;height:32px;border-radius:9px;
  background:var(--violet);color:#fff;
  display:flex;align-items:center;justify-content:center;
  font-size:14px;font-weight:800;
}
.footer p{
  font-size:13.5px;color:var(--mid);
  margin-bottom:8px;
}
.footer .links{margin-top:16px;}
.footer .links a{
  color:var(--mid);text-decoration:none;
  font-size:13.5px;margin:0 10px;
}
.footer .links a:hover{color:var(--violet-dark);}

/* ---------- CONTENT PAGE ---------- */
.page-head{
  max-width:1100px;margin:0 auto;
  padding:48px 24px 24px;text-align:center;
}
.page-head h1{
  font-size:36px;font-weight:800;
  letter-spacing:-.8px;margin-bottom:10px;
}
.page-head p{
  color:var(--mid);font-style:italic;font-size:16px;
}
.container{
  max-width:1100px;margin:0 auto;
  padding:20px 24px 60px;
}
.tbc-box{
  background:var(--card);
  border:2px dashed var(--violet);
  border-radius:16px;
  padding:36px 32px;
  text-align:center;
  transition:background .3s;
}
.tbc-box h2{
  font-size:22px;font-weight:800;color:var(--violet-dark);
  margin-bottom:12px;
}
.tbc-box p{
  font-size:15px;color:var(--mid);line-height:1.6;
  max-width:560px;margin:0 auto 24px;
}
.tbc-list{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:12px;max-width:800px;margin:0 auto;
  text-align:left;
}
.tbc-list div{
  background:var(--bg);
  border:1px solid var(--line);
  border-radius:10px;
  padding:12px 16px;
  font-size:14.5px;
  color:var(--dark);
  transition:background .3s, border-color .3s;
}
.tbc-list div::before{
  content:"📌 ";margin-right:6px;
}

/* ---------- ТАБЫ (переключение разделов) ---------- */
.tabs-wrap{
  position:sticky;
  top:60px;
  z-index:50;
  background:var(--bg);
  padding:8px 0 12px;
  margin-bottom:8px;
  transition:background .3s;
  border-bottom:1px solid var(--line);
}
.tabs{
  display:flex;
  gap:6px;
  overflow-x:auto;
  padding:6px 4px;
  scrollbar-width:thin;
  -webkit-overflow-scrolling:touch;
}
.tabs::-webkit-scrollbar{height:4px;}
.tabs::-webkit-scrollbar-thumb{background:var(--lav2);border-radius:2px;}

.tab-btn{
  flex-shrink:0;
  background:var(--card);
  color:var(--mid);
  border:1.5px solid var(--line);
  border-radius:10px;
  padding:9px 16px;
  font-family:inherit;
  font-size:13.5px;
  font-weight:700;
  cursor:pointer;
  white-space:nowrap;
  transition:all .15s;
}
.tab-btn:hover{
  border-color:var(--violet);
  color:var(--violet-dark);
  background:var(--lav);
}
.tab-btn.active{
  background:var(--violet);
  color:#fff;
  border-color:var(--violet);
  box-shadow:0 4px 12px rgba(168,85,247,.3);
}

.tab-panel{display:none;animation:fadeIn .25s ease;}
.tab-panel.active{display:block;}
@keyframes fadeIn{
  from{opacity:0;transform:translateY(6px);}
  to{opacity:1;transform:translateY(0);}
}

/* ---------- CONTENT CARDS ---------- */
.card{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:12px;
  padding:20px 24px 22px;
  margin-bottom:16px;
  box-shadow:var(--shadow-sm);
  transition:background .3s, border-color .3s;
}
.card h3{
  font-size:17px;font-weight:800;
  margin-bottom:12px;color:var(--dark);
  display:flex;align-items:center;gap:8px;flex-wrap:wrap;
}
.card h3 .tag{
  font-size:11px;font-weight:700;letter-spacing:.4px;
  text-transform:uppercase;
  color:var(--violet-dark);
  background:var(--lav);
  padding:3px 9px;border-radius:5px;
}
.card h4{font-size:15.5px;font-weight:800;margin:16px 0 8px;color:var(--violet-dark);}
.card p{margin:8px 0;}
.card ul{margin:8px 0 8px 20px;padding:0;}
.card ul li{margin-bottom:4px;}
.card ol{margin:8px 0 8px 22px;padding:0;}
.card ol li{margin-bottom:4px;}

.def{
  background:var(--lav);
  border-radius:8px;
  padding:12px 16px;
  margin:10px 0;
  font-size:15.5px;
}
.def b{color:var(--violet-dark);}

.kv{margin:10px 0;}
.kv .row{
  display:grid;grid-template-columns:minmax(160px,auto) 1fr;
  gap:10px;padding:8px 12px;
  border-bottom:1px dashed var(--line);
  border-radius:6px;
}
.kv .row:nth-child(odd){background:rgba(229,212,240,.15);}
[data-theme="dark"] .kv .row:nth-child(odd){background:rgba(168,85,247,.08);}
.kv .k{color:var(--violet-dark);font-size:14px;font-weight:700;}
.kv .v{font-size:14.5px;color:var(--dark);}

.rx{
  font-family:"Consolas","SF Mono",Menlo,monospace;
  background:var(--rx-bg);
  border-left:4px solid var(--violet);
  padding:12px 16px;
  margin:12px 0 6px;
  border-radius:0 6px 6px 0;
  font-size:15px;
  white-space:nowrap;overflow-x:auto;
  color:var(--dark);
  transition:background .3s;
}
.rx-cap{
  font-size:13px;font-style:italic;
  color:var(--mid);
  padding:0 0 16px 18px;
  margin-top:-4px;line-height:1.5;
}
.rx-cap b{color:var(--violet-dark);font-style:normal;font-weight:700;}

.warn{
  background:var(--warn-bg);border-left:4px solid var(--red);
  padding:12px 16px;border-radius:0 6px 6px 0;
  margin:12px 0;font-size:14.5px;color:var(--warn-tx);
}
.warn b{color:var(--red);}
.rule{
  background:var(--rule-bg);border-left:4px solid #2563eb;
  padding:12px 16px;border-radius:0 6px 6px 0;
  margin:12px 0;font-size:14.5px;color:var(--rule-tx);
}
.rule b{color:#2563eb;}
[data-theme="dark"] .rule b{color:#93c5fd;}
.ex{
  background:var(--ex-bg);border-left:4px solid var(--green);
  padding:12px 16px;border-radius:0 6px 6px 0;
  margin:12px 0;font-size:14.5px;color:var(--ex-tx);
}
.ex b{color:var(--green);}
.attention{
  background:var(--att-bg);border-left:4px solid var(--amber);
  padding:12px 16px;border-radius:0 6px 6px 0;
  margin:12px 0;font-size:14.5px;color:var(--att-tx);
}
.attention b{color:var(--amber);}
/* ---------- СКРЫТЫЕ ОТВЕТЫ В "ПРОВЕРЬ СЕБЯ" ---------- */
details {
  margin: 8px 0 20px;
}
details summary {
  cursor: pointer;
  color: var(--violet-dark);
  font-size: 13.5px;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 6px;
  display: inline-block;
  background: var(--lav);
  transition: background .15s;
  user-select: none;
  list-style: none;
}
details summary::-webkit-details-marker { display: none; }
details summary::before {
  content: "▸ ";
  display: inline-block;
  margin-right: 2px;
}
details[open] summary::before {
  content: "▾ ";
}
details summary:hover {
  background: var(--lav2);
}
details .rule {
  margin-top: 8px;
}

/* ---------- BACK TO TOP ---------- */
.to-top{
  position:fixed;bottom:24px;right:24px;
  width:46px;height:46px;border-radius:50%;
  background:var(--violet);color:#fff;border:none;
  font-size:20px;cursor:pointer;
  box-shadow:0 6px 20px rgba(168,85,247,.5);
  opacity:0;pointer-events:none;
  transition:opacity .25s, transform .25s;
  z-index:150;
  display:grid;place-items:center;
}
.to-top.show{opacity:1;pointer-events:auto;}
.to-top:hover{transform:translateY(-3px);}

/* ---------- PRINT ---------- */
@media print{
  body{background:#fff;color:#000;}
  .nav, .to-top, .progress-bar, .tabs-wrap{display:none !important;}
  .tab-panel{display:block !important;}
  .card{break-inside:avoid;page-break-inside:avoid;box-shadow:none;}
}

/* ---------- MOBILE ---------- */
@media(max-width:700px){
  .hero h1{font-size:34px;letter-spacing:-.8px;}
  .hero .lead{font-size:17px;}
  .section-head h2{font-size:26px;}
  .cta-block h2{font-size:26px;}
  .hero-stats{gap:28px;}
  .hero-stat .num{font-size:30px;}
  .page-head h1{font-size:28px;}
  .container{padding:16px 16px 40px;}
  .card{padding:16px 16px 18px;}
  .tabs-wrap{top:52px;}
  .tab-btn{font-size:12.5px;padding:8px 12px;}

  /* НАВИГАЦИЯ НА МОБИЛКЕ */
  .nav-inner{
    padding:8px 12px;
    gap:8px;
    flex-wrap:nowrap;
  }
  .nav-logo{
    flex-shrink:0;
  }
  .nav-logo span:not(.mark){
    display:none;
  }
  .nav-links{
    display:none;      /* скрываем ссылки — вернём бургером позже */
  }
  .nav-actions{
    gap:4px;
    margin-left:auto;
  }
  .search-input{
    width:80px;
    height:32px;
    padding:0 8px 0 26px;
    font-size:12px;
  }
  .search-input:focus{
    width:120px;
  }
  .search-wrap::before{
    left:8px;
    font-size:11px;
  }
  .icon-btn{
    width:32px;
    height:32px;
    font-size:13px;
    border-radius:7px;
  }
}
}
/* ---------- КОНСТРУКТОР АТОМА ---------- */
.constructor{
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 28px 24px;
  margin-bottom: 20px;
  transition: background .3s, border-color .3s;
}

.constructor-badge{
  display: inline-block;
  background: var(--lav);
  color: var(--violet-dark);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .6px;
  text-transform: uppercase;
  padding: 5px 12px;
  border-radius: 999px;
  margin-bottom: 12px;
}

.constructor h2{
  font-size: 26px;
  font-weight: 800;
  letter-spacing: -.4px;
  margin-bottom: 6px;
}

.constructor .subtitle{
  font-size: 14.5px;
  color: var(--mid);
  font-style: italic;
  margin-bottom: 24px;
}

/* Слайдер Z */
.slider-row{
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.slider-row label{
  font-size: 14px;
  font-weight: 700;
  color: var(--violet-dark);
  white-space: nowrap;
}

.slider-row input[type="range"]{
  flex: 1;
  min-width: 200px;
  accent-color: var(--violet);
  cursor: pointer;
}

.slider-value{
  font-size: 15px;
  font-weight: 800;
  color: var(--dark);
  min-width: 100px;
  text-align: right;
}

.slider-value .z{
  color: var(--violet-dark);
}

/* Кнопки заряда */
.charge-row{
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.charge-row .label{
  font-size: 14px;
  font-weight: 700;
  color: var(--violet-dark);
  margin-right: 8px;
}

.charge-btn{
  background: var(--card);
  color: var(--mid);
  border: 1.5px solid var(--line);
  border-radius: 8px;
  padding: 7px 14px;
  font-family: inherit;
  font-size: 13.5px;
  font-weight: 700;
  cursor: pointer;
  transition: all .15s;
}

.charge-btn:hover{
  border-color: var(--violet);
  color: var(--violet-dark);
  background: var(--lav);
}

.charge-btn.active{
  background: var(--dark);
  color: var(--bg);
  border-color: var(--dark);
}

/* Периодическая таблица 18×4 */
.ptable{
  display: grid;
  grid-template-columns: repeat(18, minmax(0, 1fr));
  gap: 4px;
  margin-bottom: 24px;
}

.ptable-cell{
  aspect-ratio: 1 / 1;
  border-radius: 6px;
  border: 1.5px solid var(--line);
  background: var(--card);
  color: var(--mid);
  font-family: inherit;
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all .15s;
  padding: 0;
}

.ptable-cell:hover{
  transform: scale(1.15);
  z-index: 2;
  box-shadow: 0 4px 14px rgba(168,85,247,.3);
}

.ptable-cell.s-block{ border-color: #A855F7; color: #7c3aed; }
.ptable-cell.p-block{ border-color: #3b82f6; color: #2563eb; }
.ptable-cell.d-block{ border-color: #10b981; color: #059669; }

[data-theme="dark"] .ptable-cell.s-block{ color: #c99fe8; }
[data-theme="dark"] .ptable-cell.p-block{ color: #93c5fd; }
[data-theme="dark"] .ptable-cell.d-block{ color: #34d399; }

.ptable-cell.active{
  background: var(--dark);
  color: var(--bg) !important;
  border-color: var(--dark);
  transform: scale(1.15);
  z-index: 3;
  box-shadow: 0 4px 14px rgba(26,11,46,.4);
}

/* Область результата (пока заглушка) */
.constructor-result{
  background: var(--bg);
  border: 1px dashed var(--line);
  border-radius: 12px;
  padding: 24px;
  text-align: center;
  color: var(--mid);
  font-size: 14.5px;
  line-height: 1.6;
  transition: background .3s, border-color .3s;
}

.constructor-result b{
  color: var(--violet-dark);
}

@media(max-width:700px){
  .constructor{padding: 20px 16px;}
  .constructor h2{font-size: 20px;}
  .slider-row{gap: 10px;}
  .slider-value{min-width: auto;}
  .ptable{gap: 2px;}
  .ptable-cell{font-size: 9px; border-radius: 3px; border-width: 1px;}
  .charge-row{gap: 4px;}
  .charge-btn{padding: 6px 10px; font-size: 12px;}
}

/* ---------- ПЕЧАТЬ (обновлённые правила) ---------- */
@media print{
  body{background:#fff !important; color:#000 !important;}
  .nav, .to-top, .progress-bar, .tabs-wrap, .icon-btn, .search-wrap, .footer .links{display:none !important;}
  .tab-panel{display:block !important;}

  /* Принудительно светлый фон — даже если была тёмная тема */
  .card, .feature, .part-card, .price-card, .step, .constructor{
    background:#fff !important;
    border-color:#ddd !important;
    color:#000 !important;
    box-shadow:none !important;
    break-inside:avoid;
    page-break-inside:avoid;
  }
  .def{background:#f3f0f7 !important; color:#000 !important;}
  .warn{background:#fef2f2 !important; color:#7f1d1d !important;}
  .rule{background:#eff6ff !important; color:#1e3a8a !important;}
  .ex{background:#f0fdf4 !important; color:#14532d !important;}
  .attention{background:#fffbeb !important; color:#78350f !important;}
  .rx{background:#faf7fc !important; color:#000 !important;}

  h1, h2, h3, h4, p, li, td, th{color:#000 !important;}
  .tag, .badge{background:#eee !important; color:#333 !important;}

  /* Чуть меньше полей для экономии бумаги */
  @page{ margin: 1.5cm; }
}
/* ---------- МОЛЕКУЛЫ (SmilesDrawer) ---------- */
.molecule{
  display:flex;
  flex-direction:column;
  align-items:center;
  background:var(--bg);
  border:1px solid var(--line);
  border-radius:10px;
  padding:16px 12px 12px;
  margin:8px 0;
  transition:background .3s, border-color .3s;
}
.molecule svg{
  max-width:100%;
  height:auto;
}
.molecule .molecule-label{
  margin-top:8px;
  font-size:13.5px;
  font-weight:700;
  color:var(--violet-dark);
  text-align:center;
}
.molecule .molecule-sub{
  margin-top:2px;
  font-family:"Consolas","SF Mono",Menlo,monospace;
  font-size:12px;
  color:var(--mid);
}
/* Две молекулы рядом (для цис/транс) */
.molecule-pair{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:12px;
  margin:12px 0;
}
@media(max-width:600px){
  .molecule-pair{grid-template-columns:1fr;}
}

/* Светлая тема — тёмные линии в SVG */
.molecule svg path,
.molecule svg line,
.molecule svg polyline{stroke:var(--dark);}
.molecule svg text{fill:var(--dark);}

/* ============================================================ */
/* СТРУКТУРНЫЕ ФОРМУЛЫ                                          */
/* ============================================================ */
/* ============================================================ */
/* СТРУКТУРНЫЕ ФОРМУЛЫ (SVG)                                     */
/* ============================================================ */
.formula {
  display: block;
  margin: 12px 0;
  padding: 6px 14px;
  background: var(--rx-bg);
  border-left: 4px solid var(--violet);
  border-radius: 0 6px 6px 0;
  overflow-x: auto;
}

/* Fallback, если строка не распарсилась */
.formula.is-text {
  padding: 12px 16px;
  font-family: "Consolas","SF Mono",Menlo,monospace;
  font-size: 13.5px;
  white-space: pre-wrap;
  line-height: 1.7;
}

/* Одна строка формулы */
.formula .f-row {
  display: block;
  padding: 0;
  margin: 0;
}
.formula .f-row + .f-row {
  border-top: 1px dashed var(--line);
  margin-top: 4px;
  padding-top: 8px;
}

.formula .f-row svg {
  display: block;
  color: var(--dark);
}

.formula .f-plain {
  display: block;
  font-family: "Consolas","SF Mono",Menlo,monospace;
  font-size: 13.5px;
  color: var(--mid);
  white-space: pre;
  line-height: 1.7;
}
/* ============================================================ */
/* 3D-МОДЕЛИ                                                     */
/* ============================================================ */
.mol3d {
  width: 100%;
  height: 260px;
  border-radius: 10px;
  overflow: hidden;
  background: #1a2233;
  margin: 12px 0;
  position: relative;
  cursor: grab;
}
.mol3d:active { cursor: grabbing; }
.mol3d canvas { display: block; width: 100% !important; height: 100% !important; }

.mol3d-hint {
  position: absolute;
  bottom: 8px;
  right: 10px;
  font-size: 11px;
  color: rgba(255,255,255,0.55);
  pointer-events: none;
  font-family: inherit;
}
.next-topic {
  display: block;
  margin: 24px 0 8px;
  padding: 16px 24px;
  background: var(--violet);
  color: #fff;
  text-decoration: none;
  border-radius: 12px;
  font-weight: 800;
  font-size: 16px;
  text-align: right;
  transition: background .15s;
}
.next-topic:hover {
  background: var(--violet-dark);
}
/* ---------- ВОПРОСЫ В "ПРОВЕРЬ СЕБЯ" ---------- */
.card .q {
  font-weight: 700;
  color: var(--dark);
  margin: 22px 0 6px;
  font-size: 15.5px;
  line-height: 1.5;
}
.card .q + ol {
  margin-top: 4px;
}
.card .q + details {
  margin-top: 4px;
}