/* ============================================================
   THE QUANTIFIER — 3lite Education
   Design System v2.0 | "Lab Terminal" Aesthetic
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Mono:ital,wght@0,400;0,700;1,400&family=DM+Sans:opsz,wght@9..40,300;9..40,400;9..40,500;9..40,600;9..40,700;9..40,800&display=swap');

/* 1. ROOT VARIABLES */
:root {
  --bg:             #080a0f;
  --bg-raised:      #0d1017;
  --bg-surface:     #121620;
  --bg-elevated:    #171d2a;
  --bg-hover:       #1e2535;
  --border:         rgba(255,255,255,0.07);
  --border-mid:     rgba(255,255,255,0.12);
  --border-strong:  rgba(255,255,255,0.22);
  --text-primary:   #e8edf5;
  --text-secondary: #6b7a99;
  --text-muted:     #3d4a63;
  --cyan:    #00e5cc;
  --blue:    #3b82f6;
  --green:   #22d3a1;
  --orange:  #f59e0b;
  --red:     #ef4444;
  --purple:  #a855f7;
  --glow-cyan:   0 0 20px rgba(0,229,204,0.3), 0 0 60px rgba(0,229,204,0.1);
  --glass:         rgba(13,16,23,0.88);
  --grad-brand:    linear-gradient(135deg, #00e5cc, #3b82f6);
  --font-ui:   'DM Sans', sans-serif;
  --font-mono: 'Space Mono', monospace;
  --r-sm:  8px; --r-md: 14px; --r-lg: 20px; --r-xl: 28px; --r-2xl: 36px;
  --ease-spring: cubic-bezier(0.175, 0.885, 0.32, 1.275);
  --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
}
body.light-mode {
  --bg:#f0f2f7; --bg-raised:#f7f8fc; --bg-surface:#ffffff; --bg-elevated:#ffffff; --bg-hover:#eef0f7;
  --border:rgba(0,0,0,0.07); --border-mid:rgba(0,0,0,0.11); --border-strong:rgba(0,0,0,0.2);
  --text-primary:#111827; --text-secondary:#6b7280; --text-muted:#9ca3af;
  --cyan:#009e8e; --blue:#2563eb; --green:#059669; --orange:#d97706; --red:#dc2626; --purple:#7c3aed;
  --glow-cyan:none; --glass:rgba(255,255,255,0.92); --grad-brand:linear-gradient(135deg,#009e8e,#2563eb);
}

/* 2. RESET */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
html{-webkit-text-size-adjust:100%;}
body{
  font-family:var(--font-ui);font-size:15px;line-height:1.5;
  color:var(--text-primary);background:var(--bg);overflow-x:hidden;min-height:100vh;
  -webkit-font-smoothing:antialiased;
  transition:background .4s var(--ease-smooth),color .4s var(--ease-smooth);
}
input,textarea,select{-webkit-user-select:text;user-select:text;}
img,svg{display:block;}
button{font-family:var(--font-ui);cursor:pointer;border:none;background:none;}

/* 3. PROTECTION */
body{
  -webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;
  -webkit-touch-callout:none;
}
input,textarea,select{-webkit-user-select:text;user-select:text;}

/* 4. BACKGROUND */
.fluid-bg{position:fixed;inset:0;z-index:0;pointer-events:none;overflow:hidden;}
.fluid-bg::before{
  content:'';position:absolute;inset:0;
  background-image:linear-gradient(rgba(0,229,204,.028) 1px,transparent 1px),linear-gradient(90deg,rgba(0,229,204,.028) 1px,transparent 1px);
  background-size:48px 48px;
  mask-image:radial-gradient(ellipse 90% 80% at 50% 0%,black 20%,transparent 100%);
  animation:grid-drift 40s linear infinite;
}
.fluid-bg::after{
  content:'';position:absolute;inset:0;
  background:radial-gradient(ellipse 70% 50% at 10% 5%,rgba(0,229,204,.055) 0%,transparent 60%),
             radial-gradient(ellipse 60% 50% at 90% 90%,rgba(59,130,246,.05) 0%,transparent 60%);
}
body.light-mode .fluid-bg::before{
  background-image:linear-gradient(rgba(0,0,0,.025) 1px,transparent 1px),linear-gradient(90deg,rgba(0,0,0,.025) 1px,transparent 1px);
  opacity:.5;
}
@keyframes grid-drift{0%{transform:translateY(0)}100%{transform:translateY(48px)}}

/* 5. LAYOUT */
.app-container{position:relative;z-index:1;width:100%;max-width:700px;margin:0 auto;padding:0 16px 56px;}

/* 6. HEADER */
.app-header{display:flex;justify-content:space-between;align-items:center;padding:20px 0 0;margin-bottom:24px;}
.brand-block{display:flex;flex-direction:column;gap:2px;}
.brand-name{font-family:var(--font-mono);font-size:13px;font-weight:700;letter-spacing:.15em;text-transform:uppercase;color:var(--cyan);text-shadow:var(--glow-cyan);}
.brand-sub{font-size:11px;font-weight:500;letter-spacing:.06em;color:var(--text-muted);text-transform:uppercase;}
.header-controls{display:flex;align-items:center;gap:12px;flex-wrap:wrap;justify-content:flex-end;}

/* Toggle pill (shared by theme + am system) */
.toggle-group{display:flex;align-items:center;gap:7px;}
.toggle-label{font-family:var(--font-mono);font-size:10px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--text-muted);}
.toggle-pill{position:relative;width:44px;height:24px;flex-shrink:0;}
.toggle-pill input{opacity:0;width:0;height:0;position:absolute;}
.toggle-track{position:absolute;inset:0;background:var(--bg-elevated);border:1px solid var(--border-mid);border-radius:100px;cursor:pointer;transition:all .3s var(--ease-smooth);}
.toggle-track::before{content:'';position:absolute;top:3px;left:3px;width:16px;height:16px;border-radius:50%;background:var(--text-muted);transition:all .3s var(--ease-spring);}
.toggle-pill input:checked+.toggle-track{background:rgba(0,229,204,.15);border-color:rgba(0,229,204,.4);}
.toggle-pill input:checked+.toggle-track::before{transform:translateX(20px);background:var(--cyan);box-shadow:0 0 8px rgba(0,229,204,.6);}
.toggle-icon{font-size:15px;line-height:1;}

/* 7. TAB BAR */
.tab-bar{display:flex;background:var(--bg-raised);border:1px solid var(--border);border-radius:var(--r-xl);padding:5px;gap:3px;margin-bottom:20px;}
.tab-btn{flex:1;text-align:center;padding:10px 6px;font-size:13px;font-weight:600;color:var(--text-secondary);border-radius:var(--r-lg);cursor:pointer;transition:all .2s var(--ease-smooth);white-space:nowrap;line-height:1.2;}
.tab-btn:hover:not(.active){color:var(--text-primary);background:var(--bg-hover);}
.tab-btn.active{background:var(--bg-elevated);color:var(--cyan);box-shadow:0 1px 8px rgba(0,0,0,.3),0 0 0 1px var(--border-mid);}
.tab-panel{display:none;animation:fade-up .35s var(--ease-smooth) both;}
.tab-panel.active{display:block;}

/* 8. PANELS */
.panel{background:var(--bg-surface);border:1px solid var(--border);border-radius:var(--r-xl);padding:24px;margin-top:16px;position:relative;overflow:hidden;transition:border-color .3s var(--ease-smooth),background .4s var(--ease-smooth);}
.panel::before{content:'';position:absolute;top:0;left:20%;right:20%;height:1px;background:linear-gradient(90deg,transparent,rgba(255,255,255,.07),transparent);}
.panel:hover{border-color:var(--border-mid);}
.panel-first{margin-top:0;}

/* 9. TYPOGRAPHY */
.section-eyebrow{font-family:var(--font-mono);font-size:10px;font-weight:700;letter-spacing:.18em;text-transform:uppercase;color:var(--cyan);margin-bottom:6px;text-shadow:var(--glow-cyan);}
.section-title{font-size:22px;font-weight:800;letter-spacing:-.5px;color:var(--text-primary);line-height:1.2;}
.section-desc{font-size:13px;color:var(--text-secondary);line-height:1.6;margin-top:4px;}

/* App icon */
.app-icon{width:68px;height:68px;border-radius:18px;background:linear-gradient(145deg,#141c2e,#0d1117);border:1px solid rgba(0,229,204,.18);box-shadow:0 0 0 1px rgba(0,229,204,.07),0 16px 40px rgba(0,0,0,.5),inset 0 1px 0 rgba(255,255,255,.05);display:flex;align-items:center;justify-content:center;margin:0 auto 16px;position:relative;overflow:hidden;}
.app-icon::after{content:'';position:absolute;top:-30%;left:-10%;width:120%;height:60%;background:linear-gradient(to bottom,rgba(0,229,204,.07),transparent);transform:rotate(-8deg);}
.app-icon svg{z-index:1;filter:drop-shadow(0 0 8px rgba(0,229,204,.5));}
body.light-mode .app-icon{background:linear-gradient(145deg,#dde3f0,#edf0f8);border-color:rgba(0,158,142,.2);box-shadow:0 8px 24px rgba(0,0,0,.08),inset 0 1px 0 rgba(255,255,255,.9);}

/* 10. INPUTS */
.input-field{width:100%;height:48px;padding:0 14px;background:var(--bg-raised);border:1px solid var(--border-mid);border-radius:var(--r-md);font-family:var(--font-mono);font-size:14px;color:var(--text-primary);outline:none;transition:all .2s var(--ease-smooth);-webkit-appearance:none;appearance:none;}
.input-field::placeholder{color:var(--text-muted);font-family:var(--font-ui);font-size:13px;}
.input-field:focus{border-color:var(--cyan);background:var(--bg-surface);box-shadow:0 0 0 3px rgba(0,229,204,.1),var(--glow-cyan);}
.input-field.error{border-color:var(--red);animation:shake .4s;}
select.input-field{cursor:pointer;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' fill='none'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%236b7a99' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 14px center;padding-right:36px;}
.input-label{font-family:var(--font-mono);font-size:10px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--text-muted);margin-bottom:6px;display:block;}
.input-row{display:flex;gap:10px;align-items:flex-end;margin-bottom:12px;}
.input-row>.input-wrap{flex:1;}
.input-wrap{display:flex;flex-direction:column;}

/* 11. BUTTONS */
.btn{display:flex;align-items:center;justify-content:center;gap:8px;width:100%;height:48px;padding:0 20px;border-radius:var(--r-md);font-family:var(--font-ui);font-size:15px;font-weight:700;cursor:pointer;border:none;outline:none;transition:all .2s var(--ease-spring);position:relative;overflow:hidden;}
.btn::after{content:'';position:absolute;inset:0;background:rgba(255,255,255,0);transition:background .15s;}
.btn:hover::after{background:rgba(255,255,255,.06);}
.btn:active{transform:scale(.97);}
.btn-cyan{background:var(--grad-brand);color:#030608;box-shadow:0 4px 20px rgba(0,229,204,.22);}
.btn-cyan:hover{box-shadow:0 6px 28px rgba(0,229,204,.38);}
.btn-ghost{background:transparent;border:1px solid var(--border-mid);color:var(--text-secondary);}
.btn-ghost:hover{border-color:var(--border-strong);color:var(--text-primary);}
.btn-sm{height:38px;font-size:13px;padding:0 14px;}
body.light-mode .btn-cyan{color:#fff;}

/* 12. SEGMENTED CONTROL */
.seg-control{display:flex;background:var(--bg-raised);border:1px solid var(--border);border-radius:var(--r-md);padding:4px;gap:2px;margin-bottom:14px;}
.seg-btn{flex:1;text-align:center;padding:8px 6px;font-size:12px;font-weight:600;color:var(--text-secondary);border-radius:var(--r-sm);cursor:pointer;transition:all .2s var(--ease-smooth);white-space:nowrap;line-height:1.2;}
.seg-btn:hover:not(.active){color:var(--text-primary);background:var(--bg-hover);}
.seg-btn.active{background:var(--bg-elevated);color:var(--cyan);box-shadow:0 1px 6px rgba(0,0,0,.25),0 0 0 1px var(--border-mid);}

/* 13. CHEM KEYBOARD */
.chem-keyboard{display:flex;gap:6px;overflow-x:auto;padding-bottom:14px;margin-bottom:14px;border-bottom:1px solid var(--border);scrollbar-width:none;}
.chem-keyboard::-webkit-scrollbar{display:none;}
.chem-key{flex:0 0 auto;padding:7px 12px;background:var(--bg-elevated);border:1px solid var(--border-mid);border-radius:var(--r-sm);font-family:var(--font-mono);font-size:12px;font-weight:700;color:var(--cyan);cursor:pointer;transition:all .12s var(--ease-smooth);white-space:nowrap;}
.chem-key:hover{background:var(--bg-hover);border-color:var(--cyan);}
.chem-key:active{background:rgba(0,229,204,.1);transform:scale(.93);box-shadow:var(--glow-cyan);}
body.light-mode .chem-key:active{box-shadow:none;}

/* 14. EQUATION PREVIEW */
.eq-preview{font-family:var(--font-mono);font-size:15px;color:var(--cyan);text-align:center;padding:13px 16px;background:var(--bg-raised);border:1px solid var(--border-mid);border-radius:var(--r-md);margin-bottom:14px;min-height:48px;display:flex;align-items:center;justify-content:center;gap:6px;flex-wrap:wrap;letter-spacing:.03em;transition:border-color .2s;}
.eq-preview.empty{color:var(--text-muted);font-family:var(--font-ui);font-size:13px;}
.eq-preview.valid{border-color:rgba(0,229,204,.3);}
.eq-preview.invalid{border-color:rgba(239,68,68,.3);color:var(--red);}

/* 15. MOLAR MASS TABLE */
.mw-table{width:100%;border-collapse:collapse;font-family:var(--font-mono);font-size:12px;}
.mw-table th{padding:6px 8px;border-bottom:1px solid var(--border-mid);color:var(--text-muted);font-weight:700;text-align:left;font-size:10px;letter-spacing:.1em;text-transform:uppercase;}
.mw-table td{padding:7px 8px;border-bottom:1px solid var(--border);color:var(--text-secondary);}
.mw-table td:first-child{color:var(--text-primary);font-weight:700;}
.mw-table td:last-child{text-align:right;color:var(--cyan);}
.mw-table tr:last-child td{border-bottom:none;}

/* 16. SPECIES CARDS */
.species-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:14px;}
.species-card{background:var(--bg-raised);border:1px solid var(--border);border-radius:var(--r-lg);padding:14px 15px;position:relative;transition:border-color .2s;animation:fade-up .35s var(--ease-smooth) both;}
.species-card:hover{border-color:var(--border-mid);}
.species-card.reactant{border-left:3px solid var(--blue);}
.species-card.product{border-left:3px solid var(--green);}
.species-card.limiting{border-color:var(--orange);border-left:3px solid var(--orange);box-shadow:0 0 0 1px rgba(245,158,11,.15),0 0 18px rgba(245,158,11,.08);}
.species-name{font-family:var(--font-mono);font-size:14px;font-weight:700;color:var(--text-primary);margin-bottom:2px;}
.species-meta{font-size:11px;color:var(--text-muted);margin-bottom:10px;}
.species-badge{display:inline-flex;align-items:center;gap:3px;font-family:var(--font-mono);font-size:9px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;padding:3px 7px;border-radius:100px;position:absolute;top:11px;right:11px;}
.badge-reactant{background:rgba(59,130,246,.1);color:var(--blue);border:1px solid rgba(59,130,246,.2);}
.badge-product{background:rgba(34,211,161,.1);color:var(--green);border:1px solid rgba(34,211,161,.2);}
.badge-limiting{background:rgba(245,158,11,.15);color:var(--orange);border:1px solid rgba(245,158,11,.3);}
.value-row{display:flex;align-items:baseline;gap:5px;margin-bottom:3px;}
.value-num{font-family:var(--font-mono);font-size:14px;font-weight:700;color:var(--text-primary);}
.value-unit{font-size:11px;color:var(--text-muted);}
.value-label{font-size:11px;color:var(--text-secondary);margin-bottom:5px;}
.excess-tag{margin-top:8px;padding:5px 8px;background:rgba(59,130,246,.07);border:1px solid rgba(59,130,246,.15);border-radius:var(--r-sm);font-size:11px;color:var(--blue);font-family:var(--font-mono);}

/* 17. RESULT CHIPS */
.results-bar{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap;}
.result-chip{flex:1;min-width:70px;background:var(--bg-raised);border:1px solid var(--border);border-radius:var(--r-lg);padding:12px 14px;text-align:center;}
.result-chip.highlight{border-color:rgba(0,229,204,.3);background:rgba(0,229,204,.04);}
.result-chip-val{font-family:var(--font-mono);font-size:17px;font-weight:700;color:var(--cyan);line-height:1;}
.result-chip-label{font-size:10px;color:var(--text-muted);margin-top:4px;}

/* 18. LIMITING BANNER */
.limiting-banner{display:flex;align-items:center;gap:10px;padding:11px 15px;background:rgba(245,158,11,.07);border:1px solid rgba(245,158,11,.2);border-radius:var(--r-md);margin-top:14px;font-size:13px;font-weight:600;color:var(--orange);animation:fade-up .3s var(--ease-spring);}

/* 19. % BY MASS BAR CHART */
.mass-breakdown{margin-top:14px;}
.mass-bar-row{display:flex;align-items:center;gap:10px;margin-bottom:10px;}
.mass-bar-label{font-family:var(--font-mono);font-size:12px;font-weight:700;color:var(--text-primary);width:28px;flex-shrink:0;}
.mass-bar-track{flex:1;height:20px;background:var(--bg-raised);border-radius:100px;overflow:hidden;border:1px solid var(--border);}
.mass-bar-fill{height:100%;border-radius:100px;transition:width .6s var(--ease-spring);}
.mass-bar-pct{font-family:var(--font-mono);font-size:12px;color:var(--text-secondary);width:52px;text-align:right;flex-shrink:0;}

/* 20. YIELD */
.yield-bar-bg{height:8px;background:var(--bg-raised);border-radius:100px;margin-top:10px;overflow:hidden;border:1px solid var(--border);}
.yield-bar-fill{height:100%;background:var(--grad-brand);border-radius:100px;transition:width .6s var(--ease-spring);width:0%;}
.info-row{display:flex;justify-content:space-between;align-items:center;font-size:12px;color:var(--text-muted);margin-top:4px;}
.info-row b{color:var(--text-secondary);}

/* 21. SPECIES INPUT BUILDER */
.species-input-card{background:var(--bg-raised);border:1px solid var(--border);border-radius:var(--r-lg);padding:16px;margin-bottom:10px;transition:border-color .2s;}
.species-input-card:hover{border-color:var(--border-mid);}
.species-input-card.reactant-inp{border-left:3px solid var(--blue);}
.species-input-card.product-inp{border-left:3px solid var(--green);}
.sic-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:10px;}
.sic-name{font-family:var(--font-mono);font-size:13px;font-weight:700;color:var(--text-primary);}
.sic-meta{font-size:11px;color:var(--text-muted);}

/* 22. GAS CONDITIONS */
.gas-conditions-bar{display:flex;gap:10px;align-items:flex-end;flex-wrap:wrap;margin-bottom:14px;}
.gas-conditions-bar .input-wrap{flex:1;min-width:100px;}

/* 23. TOAST */
#toast-container{position:fixed;top:-80px;left:50%;transform:translateX(-50%);z-index:9999;display:flex;align-items:center;gap:8px;padding:11px 20px;background:var(--bg-elevated);border:1px solid var(--border-mid);border-radius:100px;font-size:14px;font-weight:600;color:var(--text-primary);white-space:nowrap;box-shadow:0 8px 32px rgba(0,0,0,.4);transition:top .45s var(--ease-spring);}
#toast-container.show{top:20px;}
#toast-container.toast-error{border-color:rgba(239,68,68,.4);color:var(--red);}
#toast-container.toast-success{border-color:rgba(34,211,161,.4);color:var(--green);}
#toast-container.toast-info{border-color:rgba(0,229,204,.3);color:var(--cyan);}

/* 24. LOADING */
.loading-spin{width:16px;height:16px;border:2px solid rgba(0,229,204,.25);border-top-color:var(--cyan);border-radius:50%;animation:spin .6s linear infinite;flex-shrink:0;}

/* 25. ANIMATIONS */
@keyframes fade-up{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:translateY(0)}}
@keyframes shake{0%,100%{transform:translateX(0)}20%{transform:translateX(-6px)}40%{transform:translateX(6px)}60%{transform:translateX(-4px)}80%{transform:translateX(4px)}}
@keyframes spin{to{transform:rotate(360deg)}}

/* 26. UTILITIES */
sub{font-size:.65em;vertical-align:sub;}
.mt-2{margin-top:8px}.mt-3{margin-top:12px}.mt-4{margin-top:16px}.mt-5{margin-top:20px}
.text-cyan{color:var(--cyan)}.text-green{color:var(--green)}.text-orange{color:var(--orange)}.text-red{color:var(--red)}.text-muted{color:var(--text-muted)}

/* 27. LIGHT MODE */
body.light-mode .section-eyebrow,body.light-mode .brand-name{text-shadow:none;}
body.light-mode .result-chip.highlight{background:rgba(0,158,142,.05);}
html.light-mode-pending body{--bg:#f0f2f7;--bg-raised:#f7f8fc;--bg-surface:#fff;--bg-elevated:#fff;--border:rgba(0,0,0,.07);--border-mid:rgba(0,0,0,.11);--text-primary:#111827;--text-secondary:#6b7280;--text-muted:#9ca3af;--cyan:#009e8e;--blue:#2563eb;--green:#059669;--orange:#d97706;--red:#dc2626;--glow-cyan:none;--grad-brand:linear-gradient(135deg,#009e8e,#2563eb);background:#f0f2f7;color:#111827;}

/* 28. RESPONSIVE */
@media(max-width:480px){
  .app-container{padding:0 12px 36px;}
  .panel{padding:16px;border-radius:var(--r-lg);}
  .section-title{font-size:19px;}
  .species-grid{grid-template-columns:1fr;}
  .results-bar{flex-direction:column;}
  .tab-btn{font-size:11px;padding:8px 4px;}
  .header-controls{gap:8px;}
}
@media(min-width:900px){
  .app-container{max-width:860px;padding:0 32px 56px;}
  body{font-size:16px;}
  .app-header{padding-top:32px;margin-bottom:32px;}
  .panel{padding:32px 36px;border-radius:var(--r-2xl);}
  .section-title{font-size:28px;letter-spacing:-.8px;}
  .section-desc{font-size:14px;}
  .input-field{height:52px;font-size:15px;}
  .btn{height:52px;font-size:16px;}
}