/* ═══════════════════════════════════
   ГодыльХимЛаб — Железо и его соединения
   Светлая сиреневая тема
═══════════════════════════════════ */
*{margin:0;padding:0;box-sizing:border-box}
body{background:#f3eef8;color:#2d1b4e;font-family:'Segoe UI',system-ui,sans-serif;height:100vh;overflow:hidden}

/* ── NAV ── */
.nav{display:flex;align-items:center;height:52px;padding:0 16px;background:#fff;border-bottom:2px solid #e0d4f0;box-shadow:0 2px 12px rgba(140,100,180,.12);position:relative;z-index:10;gap:12px}
.nav-logo{font-size:18px;font-weight:700;color:#7c3aed;white-space:nowrap;user-select:none;flex-shrink:0}
.nav-logo span{color:#a855f7}
.nav-tabs{display:flex;gap:2px;overflow-x:auto;scrollbar-width:none}
.nav-tabs::-webkit-scrollbar{display:none}
.nav-tab{padding:6px 13px;border:none;background:transparent;color:#8b7faa;cursor:pointer;border-radius:7px;font-size:12.5px;font-weight:500;transition:.2s;white-space:nowrap}
.nav-tab:hover{background:#ede4f5;color:#5b21b6}
.nav-tab.active{background:#7c3aed;color:#fff}

/* ── SECTIONS ── */
.section{display:none;height:calc(100vh - 52px)}
.section.active{display:flex;flex-direction:column}
.scroll-wrap{flex:1;overflow-y:auto;padding:28px 20px}
.content-box{max-width:900px;margin:0 auto;width:100%}

/* ════════════════════════════════
   TOPICS CAROUSEL (главная)
════════════════════════════════ */
.topics-carousel{position:relative;flex:1;width:100%;height:100%;overflow:hidden;background:#0f0a1f}
.carousel-viewport{width:100%;height:100%;overflow:hidden}
.carousel-track{display:flex;width:100%;height:100%;transition:transform .65s cubic-bezier(.4,0,.2,1);will-change:transform}
.topic-slide{flex:0 0 100%;width:100%;height:100%;position:relative;display:flex;align-items:center;justify-content:center;overflow:hidden}

/* Slide-specific gradient backgrounds */
.topic-slide.iron{background:radial-gradient(ellipse at 20% 20%,#5b21b6 0%,transparent 55%),radial-gradient(ellipse at 80% 80%,#a855f7 0%,transparent 55%),linear-gradient(135deg,#1a0b3d 0%,#2d1b4e 40%,#4c1d95 100%)}
.topic-slide.protein{background:radial-gradient(ellipse at 25% 25%,#0e7490 0%,transparent 55%),radial-gradient(ellipse at 75% 75%,#10b981 0%,transparent 55%),linear-gradient(135deg,#042f3a 0%,#0c4a6e 40%,#065f46 100%)}

/* Decorative SVG art layer (full bleed) */
.topic-art{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;z-index:1}
.topic-art svg{width:100%;height:100%;display:block}

/* Animated glow blobs */
.topic-slide::before,.topic-slide::after{content:'';position:absolute;width:520px;height:520px;border-radius:50%;filter:blur(120px);opacity:.45;pointer-events:none;z-index:0;animation:blobFloat 14s ease-in-out infinite}
.topic-slide.iron::before{background:#a855f7;top:-180px;left:-140px}
.topic-slide.iron::after{background:#ec4899;bottom:-200px;right:-160px;animation-delay:-7s}
.topic-slide.protein::before{background:#14b8a6;top:-180px;right:-140px}
.topic-slide.protein::after{background:#3b82f6;bottom:-200px;left:-160px;animation-delay:-7s}
@keyframes blobFloat{0%,100%{transform:translate(0,0) scale(1)}50%{transform:translate(30px,-30px) scale(1.1)}}

/* Slide content */
.topic-content{position:relative;z-index:3;text-align:center;padding:40px 24px;max-width:820px;width:100%}
.topic-badge{display:inline-block;padding:7px 18px;background:rgba(255,255,255,.12);backdrop-filter:blur(8px);border:1px solid rgba(255,255,255,.22);border-radius:24px;font-size:12px;color:#fff;font-weight:600;margin-bottom:22px;letter-spacing:.3px}
.topic-content h1{font-size:54px;color:#fff;margin-bottom:14px;line-height:1.1;font-weight:800;text-shadow:0 6px 30px rgba(0,0,0,.35);letter-spacing:-1px}
.topic-content .topic-sub{color:rgba(255,255,255,.88);font-size:15px;line-height:1.6;margin-bottom:32px;max-width:620px;margin-left:auto;margin-right:auto}
.topic-cards{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-bottom:32px}
.topic-card{background:rgba(255,255,255,.12);backdrop-filter:blur(10px);border:1px solid rgba(255,255,255,.22);border-radius:12px;padding:12px 18px;display:flex;align-items:center;gap:8px;color:#fff;font-size:13px;font-weight:600;transition:.2s}
.topic-card:hover{background:rgba(255,255,255,.18);transform:translateY(-2px)}
.tc-icon{font-size:20px}
.topic-btn{padding:14px 36px;background:#fff;color:#2d1b4e;border:none;border-radius:12px;font-size:15px;font-weight:700;cursor:pointer;transition:.2s;box-shadow:0 8px 24px rgba(0,0,0,.25);letter-spacing:.2px}
.topic-btn:hover{transform:translateY(-2px);box-shadow:0 12px 32px rgba(0,0,0,.35)}
.topic-btn.disabled{background:rgba(255,255,255,.18);color:rgba(255,255,255,.85);cursor:not-allowed;backdrop-filter:blur(8px);border:1px solid rgba(255,255,255,.25);box-shadow:none}
.topic-btn.disabled:hover{transform:none;box-shadow:none}
.topic-soon{display:inline-block;margin-left:10px;padding:3px 10px;background:#fbbf24;color:#78350f;border-radius:12px;font-size:11px;font-weight:700;letter-spacing:.5px;vertical-align:middle}

/* Carousel controls */
.carousel-nav{position:absolute;top:50%;transform:translateY(-50%);width:52px;height:52px;border-radius:50%;background:rgba(255,255,255,.14);backdrop-filter:blur(10px);border:1.5px solid rgba(255,255,255,.28);color:#fff;font-size:30px;line-height:1;cursor:pointer;z-index:10;transition:.2s;display:flex;align-items:center;justify-content:center;font-weight:300}
.carousel-nav:hover{background:rgba(255,255,255,.26);transform:translateY(-50%) scale(1.08)}
.carousel-nav.prev{left:24px}
.carousel-nav.next{right:24px}
.carousel-dots{position:absolute;bottom:28px;left:50%;transform:translateX(-50%);display:flex;gap:10px;z-index:10}
.carousel-dot{width:10px;height:10px;border-radius:50%;background:rgba(255,255,255,.35);cursor:pointer;transition:.25s;border:none;padding:0}
.carousel-dot.active{background:#fff;width:32px;border-radius:5px}
.carousel-dot:hover{background:rgba(255,255,255,.6)}
.carousel-counter{position:absolute;top:24px;right:28px;color:rgba(255,255,255,.78);font-size:12px;font-weight:600;letter-spacing:1px;z-index:10;background:rgba(255,255,255,.08);backdrop-filter:blur(6px);padding:6px 12px;border-radius:20px;border:1px solid rgba(255,255,255,.15)}

@media(max-width:700px){
  .topic-content h1{font-size:34px}
  .topic-content .topic-sub{font-size:13px}
  .carousel-nav{width:42px;height:42px;font-size:24px}
  .carousel-nav.prev{left:10px}
  .carousel-nav.next{right:10px}
  .topic-card{padding:10px 14px;font-size:12px}
}

/* ── HERO (legacy, не используется главной — оставлен для совместимости) ── */
.hero{flex:1;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#f3eef8 0%,#e8daf6 50%,#dcc8f0 100%);overflow-y:auto}
.hero-inner{text-align:center;padding:30px 20px;max-width:700px}
.hero-badge{display:inline-block;padding:5px 16px;background:#fff;border:1.5px solid #e0d4f0;border-radius:20px;font-size:12px;color:#7c3aed;font-weight:600;margin-bottom:18px}
.hero-inner h1{font-size:32px;color:#2d1b4e;margin-bottom:10px;line-height:1.2}
.hero-sub{color:#7c6f9b;font-size:14px;margin-bottom:28px;line-height:1.5}
.hero-cards{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;margin-bottom:28px}
.hero-card{background:#fff;border:1.5px solid #e0d4f0;border-radius:12px;padding:14px 20px;display:flex;align-items:center;gap:10px;transition:.2s}
.hero-card:hover{border-color:#a78bfa;transform:translateY(-2px)}
.hc-icon{font-size:22px}
.hc-text{font-size:13px;font-weight:600;color:#4a3670}
.hero-btn{padding:12px 32px;background:#7c3aed;color:#fff;border:none;border-radius:10px;font-size:15px;font-weight:600;cursor:pointer;transition:.2s}
.hero-btn:hover{background:#6d28d9;transform:translateY(-1px)}

/* ── CARDS ── */
.card{background:#fff;border:1.5px solid #e0d4f0;border-radius:12px;padding:20px;margin-bottom:16px}
.card-title{font-size:16px;font-weight:700;color:#2d1b4e;margin-bottom:10px}
.card-subtitle{font-size:11px;color:#8b7faa;text-transform:uppercase;letter-spacing:.5px;margin-bottom:6px}
.card h3{font-size:15px;font-weight:600;color:#7c3aed;margin:14px 0 8px}
.card p,.card li{font-size:13px;color:#4a3670;line-height:1.7}
.card ul,.card ol{padding-left:20px}
.card li{margin-bottom:4px}

/* colored borders */
.card-danger{border-left:4px solid #ef4444}
.card-success{border-left:4px solid #22c55e}
.card-warn{border-left:4px solid #f59e0b}
.card-info{border-left:4px solid #3b82f6}
.card-purple{border-left:4px solid #7c3aed}

/* ── EQUATION BOX ── */
.eq{font-family:'Courier New',monospace;font-size:13px;color:#059669;background:#f0fdf4;padding:10px 14px;border-radius:8px;border:1px solid #bbf7d0;margin:8px 0;word-break:break-all}
.eq.purple{color:#7c3aed;background:#faf5ff;border-color:#e0d4f0}

/* ── EXPERIMENT ── */
.exp-header{text-align:center;padding:20px 0 10px}
.exp-header h2{font-size:22px;color:#7c3aed}
.exp-header p{font-size:13px;color:#7c6f9b;margin-top:4px}
.equipment-grid{display:flex;gap:10px;flex-wrap:wrap;margin:10px 0}
.eq-item{background:#faf5ff;border:1px solid #e0d4f0;border-radius:8px;padding:8px 14px;font-size:12px;color:#4a3670;display:flex;align-items:center;gap:6px}
.eq-dot{width:10px;height:10px;border-radius:50%;flex-shrink:0}
.step-list{counter-reset:steps}
.step-list li{counter-increment:steps;list-style:none;position:relative;padding:10px 10px 10px 44px;background:#faf5ff;border-radius:8px;margin-bottom:8px;font-size:13px;color:#4a3670;line-height:1.6}
.step-list li::before{content:counter(steps);position:absolute;left:10px;top:10px;width:24px;height:24px;border-radius:50%;background:#7c3aed;color:#fff;font-size:12px;font-weight:700;display:flex;align-items:center;justify-content:center}

/* reaction result card */
.result-card{background:#f0fdf4;border:1.5px solid #bbf7d0;border-radius:12px;padding:16px;margin-top:16px;display:none}
.result-card.show{display:block}
.result-card h4{color:#16a34a;margin-bottom:8px;font-size:14px}

/* ── INTERACTIVE ZONE ── */
.chem-zone{display:flex;gap:12px;flex-wrap:wrap;justify-content:center;margin:16px 0}
.chem-beaker{width:100px;height:130px;border:2px solid #e0d4f0;border-radius:0 0 12px 12px;border-top:none;position:relative;cursor:pointer;transition:.2s;display:flex;flex-direction:column;align-items:center;justify-content:flex-end;padding-bottom:6px;background:#fff}
.chem-beaker::before{content:'';position:absolute;top:0;left:-2px;right:-2px;height:8px;border:2px solid #e0d4f0;border-bottom:none;border-radius:4px 4px 0 0;background:#fff}
.chem-beaker:hover{border-color:#a78bfa}
.chem-beaker.selected{border-color:#7c3aed;box-shadow:0 0 0 3px rgba(124,58,237,.15)}
.chem-beaker.dropped{border-color:#22c55e}
.beaker-liquid{position:absolute;bottom:0;left:0;right:0;border-radius:0 0 10px 10px;transition:height .6s,background .6s}
.beaker-label{position:relative;z-index:1;font-size:10px;color:#4a3670;text-align:center;font-weight:600}
.beaker-formula{font-size:9px;color:#8b7faa;font-weight:400}

.mix-btn{padding:10px 28px;background:#7c3aed;color:#fff;border:none;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer;transition:.2s;margin:10px auto;display:block}
.mix-btn:hover{background:#6d28d9}
.mix-btn:disabled{background:#e0d4f0;color:#a89cc0;cursor:not-allowed}
.observation{background:#fef3c7;border:1px solid #fde68a;border-radius:8px;padding:12px;font-size:13px;color:#92400e;margin:12px 0;display:none}
.observation.show{display:block}

/* ── TASKS ── */
.task-block{background:#fff;border:1.5px solid #e0d4f0;border-radius:12px;padding:20px;margin-bottom:20px}
.task-block h3{font-size:15px;color:#7c3aed;margin-bottom:12px}
.task-option{display:block;padding:10px 14px;margin:5px 0;border-radius:8px;border:1.5px solid #e0d4f0;cursor:pointer;transition:.15s;background:#faf5ff;font-size:13px;color:#2d1b4e}
.task-option:hover{border-color:#a78bfa;background:#ede4f5}
.task-option.correct{border-color:#22c55e;background:#dcfce7;color:#166534}
.task-option.wrong{border-color:#ef4444;background:#fef2f2;color:#991b1b}
.task-option.disabled{pointer-events:none;opacity:.7}
.task-feedback{margin-top:10px;padding:12px;border-radius:8px;font-size:13px;line-height:1.6;display:none}
.task-feedback.show{display:block}
.task-feedback.ok{background:#dcfce7;color:#166534;border:1px solid #bbf7d0}
.task-feedback.err{background:#fef2f2;color:#991b1b;border:1px solid #fecaca}

.coeff-input{width:36px;height:28px;text-align:center;border:1.5px solid #e0d4f0;border-radius:6px;font-size:14px;font-family:monospace;margin:0 2px;color:#7c3aed;font-weight:700;outline:none}
.coeff-input:focus{border-color:#7c3aed}
.coeff-input.ok{border-color:#22c55e;background:#dcfce7}
.coeff-input.err{border-color:#ef4444;background:#fef2f2}

textarea.fb-area{width:100%;height:80px;border:1.5px solid #e0d4f0;border-radius:8px;padding:10px;font-size:13px;font-family:inherit;resize:vertical;outline:none;color:#2d1b4e}
textarea.fb-area:focus{border-color:#7c3aed}
.conclusion-area{width:100%;min-height:100px;border:1.5px solid #e0d4f0;border-radius:8px;padding:10px;font-size:13px;font-family:inherit;resize:vertical;outline:none;color:#2d1b4e}
.conclusion-area:focus{border-color:#7c3aed}

/* ── RATING ── */
.stars{display:flex;gap:6px;margin:10px 0}
.star{font-size:28px;cursor:pointer;color:#e0d4f0;transition:.15s}
.star:hover,.star.active{color:#f59e0b}
.fb-submit{padding:10px 28px;background:#7c3aed;color:#fff;border:none;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer;transition:.2s;margin-top:10px}
.fb-submit:hover{background:#6d28d9}
.fb-thanks{display:none;padding:20px;text-align:center;color:#16a34a;font-size:15px;font-weight:600}

/* ── SCROLLBAR ── */
::-webkit-scrollbar{width:5px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:#d8c4e8;border-radius:3px}

/* ── SAFETY ICONS ── */
.safety-icons{display:flex;gap:20px;justify-content:center;flex-wrap:wrap;margin:16px 0}
.safety-icon{text-align:center}
.safety-icon .emoji{font-size:30px}
.safety-icon .label{font-size:10px;color:#7c6f9b;margin-top:4px}

/* ── PAGE TITLE ── */
.page-title{font-size:22px;color:#7c3aed;margin-bottom:6px}
.page-desc{color:#8b7faa;font-size:13px;margin-bottom:20px}

/* ════════════════════════════════
   3D LAB LAYOUT
════════════════════════════════ */
.lab-layout{display:flex;height:100%;overflow:hidden;position:relative}
.lab-panel{width:260px;flex-shrink:0;background:#fff;border-right:2px solid #e0d4f0;overflow-y:auto;padding:14px;display:flex;flex-direction:column;gap:4px;position:relative;z-index:2}
.lab-panel-header{font-size:13px;font-weight:700;color:#7c3aed;margin-bottom:4px}
.lab-panel-goal{font-size:11px;color:#7c6f9b;margin-bottom:8px;line-height:1.4}
.lab-panel-group{margin-bottom:12px}
.lab-panel-group-title{font-size:10px;font-weight:700;color:#8b7faa;text-transform:uppercase;letter-spacing:.7px;margin-bottom:8px;padding-bottom:4px;border-bottom:1px solid #e0d4f0}
.lab-panel-grid{display:grid;grid-template-columns:1fr;gap:8px}
.lab-panel-card{display:flex;flex-direction:column;align-items:center;padding:10px 6px 8px;border-radius:10px;border:1.5px solid #e0d4f0;background:#faf5ff;cursor:pointer;transition:.2s;text-align:center;user-select:none}
.lab-panel-card:hover{border-color:#a78bfa;background:#ede4f5;transform:translateY(-1px);box-shadow:0 2px 8px rgba(124,58,237,.1)}
.lab-panel-card.selected{border-color:#7c3aed;background:#e9ddf7;box-shadow:0 0 0 3px rgba(124,58,237,.2)}
.lab-panel-card.placed{opacity:.35;cursor:default;pointer-events:none;transform:none;box-shadow:none}
.lpc-icon{font-size:32px;margin-bottom:4px;line-height:1}
.lpc-dot{width:28px;height:28px;border-radius:50%;margin-bottom:4px;border:2px solid rgba(0,0,0,.08)}
.lpc-name{font-size:10.5px;font-weight:600;color:#4a3670;line-height:1.3}
.lpc-formula{font-size:9.5px;color:#8b7faa;margin-top:1px}
.lpc-type{font-size:9px;color:#a89cc0;font-style:italic;margin-top:2px}
.lab-panel-card.info-only{cursor:default;pointer-events:none;opacity:0.85}

.lab-scene-wrap{flex:1;position:relative;min-width:0;background:#2a2435;overflow:hidden}
.lab-canvas{width:100%;height:100%;display:block;touch-action:none;position:relative;z-index:0}
.lab-loading{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);font-size:14px;color:#7c6f9b;text-align:center;z-index:1;padding:20px}
.lab-hud{position:absolute;bottom:0;left:0;right:0;padding:12px 16px;display:flex;flex-direction:column;gap:8px;pointer-events:none;z-index:5}
.lab-hud>*{pointer-events:auto}
.hud-bar{background:rgba(255,255,255,.92);backdrop-filter:blur(8px);border:1px solid #e0d4f0;border-radius:10px;padding:12px 16px;font-size:13px;color:#4a3670}
.hud-bar h4{color:#7c3aed;margin-bottom:4px;font-size:13px}
.hud-title{position:absolute;top:12px;left:16px;right:16px;pointer-events:none;display:flex;justify-content:space-between;align-items:flex-start;z-index:5}
.hud-title-left h3{font-size:15px;color:#7c3aed;background:rgba(255,255,255,.88);backdrop-filter:blur(6px);display:inline-block;padding:6px 14px;border-radius:8px;border:1px solid #e0d4f0}
.hud-title-left p{font-size:11px;color:#7c6f9b;margin-top:4px;background:rgba(255,255,255,.75);display:inline-block;padding:3px 10px;border-radius:6px}
.undo-btn{pointer-events:auto;padding:8px 16px;background:rgba(255,255,255,.92);backdrop-filter:blur(6px);border:1.5px solid #e0d4f0;border-radius:8px;font-size:12px;font-weight:600;color:#7c3aed;cursor:pointer;transition:.2s;display:flex;align-items:center;gap:5px;flex-shrink:0}
.undo-btn:hover{background:#fff;border-color:#a78bfa;box-shadow:0 2px 8px rgba(124,58,237,.12)}
.undo-btn:disabled{opacity:.4;cursor:not-allowed}
.hud-mix-btn{padding:10px 28px;background:#7c3aed;color:#fff;border:none;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer;transition:.2s;align-self:center}
.hud-mix-btn:hover{background:#6d28d9}
.hud-mix-btn:disabled{background:#c4b5d8;cursor:not-allowed}
.hud-obs{background:rgba(254,243,199,.95);border:1px solid #fde68a;color:#92400e}
.hud-result .eq{margin:6px 0}

.drop-hint{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);font-size:13px;color:#a89cc0;pointer-events:none;text-align:center}

/* Vessel action menu */
.vessel-menu{position:absolute;z-index:20;background:#fff;border:1.5px solid #e0d4f0;border-radius:10px;padding:6px;min-width:200px;box-shadow:0 4px 20px rgba(124,58,237,.18);animation:vmPop .15s ease}
@keyframes vmPop{from{transform:scale(.9);opacity:0}to{transform:scale(1);opacity:1}}
.vm-title{font-size:12px;font-weight:700;color:#7c3aed;padding:6px 10px;border-bottom:1px solid #e0d4f0;margin-bottom:4px}
.vm-btn{padding:8px 12px;font-size:12px;color:#2d1b4e;border-radius:6px;cursor:pointer;transition:.15s}
.vm-btn:hover{background:#ede4f5;color:#7c3aed}
.vm-hint{padding:8px 12px;font-size:11px;color:#8b7faa;font-style:italic}
.vm-close{padding:6px 12px;font-size:11px;color:#8b7faa;text-align:center;cursor:pointer;border-top:1px solid #e0d4f0;margin-top:4px}
.vm-close:hover{color:#7c3aed}

/* Steps in experiment panel */
.lab-steps{list-style:none;counter-reset:labstep;padding:0;margin:0}
.lab-steps li{counter-increment:labstep;position:relative;padding:6px 6px 6px 28px;font-size:11px;color:#4a3670;line-height:1.5;border-bottom:1px solid #f0e8f8}
.lab-steps li:last-child{border-bottom:none}
.lab-steps li::before{content:counter(labstep);position:absolute;left:4px;top:6px;width:18px;height:18px;border-radius:50%;background:#7c3aed;color:#fff;font-size:10px;font-weight:700;display:flex;align-items:center;justify-content:center}

@media(max-width:700px){
  .nav-logo{font-size:15px}
  .nav-tab{font-size:11px;padding:5px 8px}
  .hero-inner h1{font-size:24px}
  .content-box{padding:0 4px}
}

/* ════════════════════════════════
   3D МОЛЕКУЛЯРНЫЙ ПРОСМОТРЩИК
════════════════════════════════ */
.mol-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px;margin-bottom:16px}
.mol-card{background:#fff;border:1.5px solid #e0d4f0;border-radius:14px;overflow:hidden;transition:.2s}
.mol-card:hover{border-color:#a78bfa;box-shadow:0 4px 16px rgba(124,58,237,.12)}
.mol-canvas{width:100%;height:280px;display:block;cursor:grab;background:#0f0a1f;touch-action:none}
.mol-canvas:active{cursor:grabbing}
.mol-info{padding:14px 16px 16px}
.mol-title{font-size:16px;font-weight:700;margin-bottom:2px}
.mol-formula{font-size:12px;color:#7c3aed;font-family:'Courier New',monospace;margin-bottom:4px}
.mol-desc{font-size:12px;color:#7c6f9b;line-height:1.5}
.mol-hint{font-size:11px;color:#a89cc0;margin-top:6px;font-style:italic}
.mol-legend-item{display:inline-flex;align-items:center;gap:5px;font-size:12px;color:#4a3670}
.mol-dot{width:13px;height:13px;border-radius:50%;display:inline-block;flex-shrink:0}
@media(max-width:640px){
  .mol-grid{grid-template-columns:1fr}
  .mol-canvas{height:220px}
}

/* ═══════════════════════════════════════════════
   RESPONSIVE — ADAPTIVE LAYOUT
═══════════════════════════════════════════════ */

/* ── Large desktop (≥ 1400px) ── */
@media(min-width:1400px){
  .content-box{max-width:1100px}
  .topic-content{max-width:1000px}
  .topic-content h1{font-size:64px}
  .lab-panel{width:300px}
  .mol-canvas{height:340px}
  .mol-grid{grid-template-columns:repeat(2,1fr)}
}

/* ── Tablet (≤ 1024px) ── */
@media(max-width:1024px){
  .lab-panel{width:210px}
  .topic-content h1{font-size:44px}
  .topic-content .topic-sub{font-size:14px}
}

/* ── Mobile (≤ 640px) ── */
@media(max-width:640px){
  /* Use dynamic viewport height to account for mobile browser chrome */
  body{height:100dvh}
  .section{height:calc(100dvh - 52px)}

  /* Nav */
  .nav{padding:0 8px;gap:6px}
  .nav-logo{font-size:13px}
  .nav-tab{font-size:10px;padding:5px 7px}

  /* Carousel */
  .topic-content{padding:20px 14px}
  .topic-content h1{font-size:26px;letter-spacing:-.5px}
  .topic-content .topic-sub{font-size:12px;margin-bottom:18px}
  .topic-badge{font-size:10px;padding:5px 12px;margin-bottom:12px}
  .topic-cards{gap:6px;margin-bottom:20px}
  .topic-card{padding:7px 10px;font-size:11px}
  .tc-icon{font-size:15px}
  .topic-btn{padding:11px 24px;font-size:13px}
  .carousel-nav{width:36px;height:36px;font-size:20px}
  .carousel-nav.prev{left:6px}
  .carousel-nav.next{right:6px}
  .carousel-dots{bottom:12px;gap:7px}
  .carousel-counter{top:10px;right:10px;font-size:10px;padding:3px 8px}
  /* Reduce blob size on mobile for performance */
  .topic-slide::before,.topic-slide::after{width:300px;height:300px;filter:blur(70px)}

  /* 3D Lab: panel as slide-in drawer overlay */
  .lab-panel{
    position:fixed;
    left:0;top:52px;bottom:0;
    width:min(85vw,300px);
    height:auto;
    transform:translateX(-100%);
    transition:transform .3s cubic-bezier(.4,0,.2,1);
    z-index:100;
    overflow-y:auto;overflow-x:hidden;
    border-right:2px solid #e0d4f0;
    padding:14px;gap:4px;
    flex-direction:column;
    box-shadow:4px 0 24px rgba(0,0,0,.18)
  }
  .lab-panel.open{transform:translateX(0)}
  .lab-scene-wrap{width:100%}

  /* Backdrop behind open drawer */
  .panel-backdrop{
    display:none;
    position:fixed;inset:0;top:52px;
    background:rgba(0,0,0,.4);
    z-index:99
  }
  .panel-backdrop.show{display:block}

  /* Toggle button */
  .panel-toggle{
    display:flex;
    align-items:center;gap:5px;
    position:absolute;top:10px;left:10px;z-index:10;
    padding:7px 13px;
    background:rgba(255,255,255,.92);backdrop-filter:blur(6px);
    border:1.5px solid #e0d4f0;border-radius:8px;
    font-size:12px;font-weight:600;color:#7c3aed;
    cursor:pointer;transition:.2s;white-space:nowrap
  }
  .panel-toggle:hover{background:#fff;border-color:#a78bfa}

  /* HUD adjustments */
  .hud-bar{font-size:12px;padding:8px 12px}
  .hud-bar h4{font-size:12px}
  .hud-title-left h3{font-size:12px;padding:4px 10px}
  .hud-title-left p{display:none}
  .undo-btn{padding:6px 10px;font-size:11px}
  .hud-mix-btn{padding:8px 18px;font-size:13px}
  .drop-hint{font-size:12px}

  /* Vessel context menu */
  .vessel-menu{min-width:180px}
  .vm-btn{padding:10px 12px;font-size:13px}

  /* Content sections */
  .scroll-wrap{padding:14px 10px}
  .content-box{padding:0 2px}
  .card{padding:14px 12px;margin-bottom:12px}
  .card-title{font-size:14px}
  .card p,.card li{font-size:12.5px}
  .page-title{font-size:18px}
  .page-desc{font-size:12px;margin-bottom:14px}

  /* Experiment */
  .exp-header h2{font-size:18px}
  .equipment-grid{gap:6px}
  .eq-item{font-size:11px;padding:5px 9px}
  .step-list li{font-size:12px;padding:8px 8px 8px 38px}

  /* Tasks */
  .task-block{padding:14px 12px}
  .task-option{padding:11px 12px;font-size:12.5px}
  .coeff-input{width:40px;height:32px;font-size:15px}

  /* Rating — larger touch targets */
  .star{font-size:36px}
  .fb-submit{width:100%;padding:12px}
}

/* ── Toggle hidden on desktop ── */
@media(min-width:641px){
  .panel-toggle{display:none}
  .panel-backdrop{display:none!important}
}

/* ── Small phones (≤ 380px) ── */
@media(max-width:380px){
  .nav-logo{font-size:11px}
  .nav-tab{font-size:9.5px;padding:4px 6px}
  .topic-content h1{font-size:22px}
  .lab-panel{width:92vw}
  .scroll-wrap{padding:10px 8px}
}