/* BulkCalculator - Chemistry Tools shared stylesheet */
:root{--bg:#f7f9fc;--card:#fff;--ink:#1a2332;--ink-soft:#4a5568;--muted:#718096;--border:#e2e8f0;--primary:#2563eb;--primary-dark:#1d4ed8;--accent:#0d9488;--success:#059669;--warn:#d97706;--danger:#dc2626;--violet:#7c3aed;--radius:12px;--shadow:0 1px 3px rgba(0,0,0,.05),0 1px 2px rgba(0,0,0,.03);--shadow-md:0 4px 12px rgba(0,0,0,.06);--grad-hero:linear-gradient(135deg,#eff6ff 0%,#ecfeff 50%,#f5f3ff 100%)}
*{box-sizing:border-box}html,body{margin:0;padding:0;overflow-x:hidden}body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--ink);line-height:1.6;font-size:16px}a{color:var(--primary);text-decoration:none}a:hover{text-decoration:underline}
.site-header{background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:100}.nav-wrap{max-width:1200px;margin:0 auto;padding:14px 20px;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}.brand{font-weight:700;font-size:20px;color:var(--ink);display:flex;align-items:center;gap:8px}.brand .diamond{color:var(--primary)}.nav-toggle{display:none;background:none;border:1px solid var(--border);padding:6px 10px;border-radius:6px;cursor:pointer;font-size:18px}.nav-menu{display:flex;list-style:none;margin:0;padding:0;gap:6px}.nav-menu>li{position:relative}.nav-menu>li>a,.nav-menu>li>span{padding:8px 14px;display:block;color:var(--ink);font-weight:500;cursor:pointer;border-radius:6px}.nav-menu>li>a:hover,.nav-menu>li>span:hover{background:#f1f5f9;text-decoration:none}.dropdown{display:none;position:absolute;top:100%;left:0;background:#fff;border:1px solid var(--border);border-radius:8px;box-shadow:var(--shadow-md);min-width:240px;padding:8px;z-index:101}.nav-menu>li:hover .dropdown{display:block}.dropdown li{list-style:none}.dropdown a{display:block;padding:8px 12px;color:var(--ink-soft);border-radius:6px;font-size:14px}.dropdown a:hover{background:#f1f5f9;color:var(--primary);text-decoration:none}header .dropdown{min-width:220px;max-width:calc(100vw - 40px)}header .nav-menu>li:first-child .dropdown{min-width:400px;grid-template-columns:1fr 1fr;padding:8px}header .nav-menu>li:first-child:hover .dropdown{display:grid;column-gap:6px}header .nav-menu>li:last-child .dropdown{left:auto;right:0}header .dropdown a{font-size:13px;padding:7px 10px;line-height:1.25;white-space:normal}
.container{max-width:1200px;margin:0 auto;padding:24px 20px 60px}.container-narrow{max-width:980px;margin:0 auto;padding:24px 20px 60px}.breadcrumb,.crumbs{max-width:1200px;font-size:13px;color:var(--muted);margin:0 auto 18px;padding:10px 20px}.breadcrumb{padding:0;margin-bottom:18px}.breadcrumb a,.crumbs a{color:var(--muted)}h1{font-size:32px;margin:0 0 10px;letter-spacing:-.02em;color:var(--ink)}h2{font-size:22px;margin:32px 0 12px;padding-left:12px;border-left:3px solid var(--primary);color:var(--ink)}h3{font-size:18px;margin:20px 0 10px;color:var(--ink)}p{margin:10px 0}ul,ol{padding-left:22px}li{margin:6px 0}
.chem-hero{background:var(--grad-hero);border-bottom:1px solid var(--border)}.chem-hero-inner{max-width:1200px;margin:0 auto;padding:50px 20px 40px;text-align:center}.chem-hero h1{font-size:2.4rem;margin:0 0 12px;background:linear-gradient(90deg,#2563eb,#0d9488,#7c3aed);-webkit-background-clip:text;background-clip:text;color:transparent}.chem-hero p{font-size:1.1rem;color:var(--ink-soft);max-width:780px;margin:0 auto 20px}.badges{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}.badge{background:#fff;border:1px solid var(--border);color:var(--primary);padding:5px 12px;border-radius:999px;font-size:12px;font-weight:600;box-shadow:var(--shadow)}.chem-search{max-width:720px;margin:24px auto 0;position:relative}.chem-search input{width:100%;padding:14px 18px 14px 44px;border:1px solid var(--border);border-radius:999px;font-size:15px;background:#fff;box-shadow:var(--shadow)}.chem-search input:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.15)}.chem-search:before{content:"Search";position:absolute;left:15px;top:50%;transform:translateY(-50%);font-size:11px;color:var(--muted)}
.cat-block{max-width:1200px;margin:40px auto 0;padding:0 20px}.cat-head{display:flex;align-items:center;gap:14px;margin-bottom:14px}.cat-icon{width:44px;height:44px;border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:15px;font-weight:800;flex-shrink:0;background:linear-gradient(135deg,#dbeafe,#ccfbf1);color:#1e40af}.cat-head h2{margin:0;padding:0;border:none;font-size:1.4rem}.cat-head .cat-sub{color:var(--muted);font-size:.95rem;margin:2px 0 0}.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:14px;margin-top:6px}.tool{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow);transition:transform .15s ease,box-shadow .15s ease,border-color .15s;display:block;color:inherit;text-decoration:none}.tool:hover{transform:translateY(-2px);box-shadow:var(--shadow-md);border-color:#c7d2fe;text-decoration:none}.tool .ico{width:32px;height:32px;border-radius:10px;display:flex;align-items:center;justify-content:center;background:#f0fdfa;color:#0f766e;font-weight:800;margin-bottom:8px}.tool h3{font-size:1rem;margin:0 0 4px;color:var(--primary)}.tool p{font-size:.88rem;color:var(--muted);margin:0}.content-block{max-width:1200px;margin:40px auto 0;padding:24px 20px;background:#fff;border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow)}
.tool-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow);margin:18px 0}.tool-tagline{color:var(--muted);margin:-4px 0 18px}.field{margin-bottom:14px}.field label{display:block;font-weight:600;font-size:14px;margin-bottom:6px;color:var(--ink)}.field .hint{font-size:12px;color:var(--muted);margin-top:4px}.field-row{display:grid;grid-template-columns:1fr 140px;gap:10px}.field-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px}input[type=text],input[type=number],input[type=search],select,textarea{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:8px;font-size:15px;font-family:inherit;background:#fff;color:var(--ink);transition:border-color .15s,box-shadow .15s}input:focus,select:focus,textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.15)}textarea{resize:vertical;min-height:110px;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:13px}
.btn-row{display:flex;gap:10px;flex-wrap:wrap;margin-top:16px}.btn{padding:10px 18px;border-radius:8px;font-size:15px;font-weight:600;cursor:pointer;border:1px solid transparent;transition:all .15s;font-family:inherit;display:inline-flex;align-items:center;gap:6px}.btn-primary{background:var(--primary);color:#fff}.btn-primary:hover{background:var(--primary-dark)}.btn-secondary{background:#fff;color:var(--ink-soft);border-color:var(--border)}.btn-secondary:hover{background:#f1f5f9;color:var(--ink)}.btn-accent{background:var(--accent);color:#fff}.btn:disabled{opacity:.5;cursor:not-allowed}
.result-card{background:#f0f9ff;border:1px solid #bae6fd;border-radius:var(--radius);padding:20px;margin-top:18px}.result-card h3{margin-top:0;display:flex;align-items:center;justify-content:space-between;gap:10px}.copy-btn{background:#fff;border:1px solid var(--border);border-radius:6px;padding:6px 10px;cursor:pointer;font-size:13px}.result-row{display:flex;justify-content:space-between;align-items:flex-start;padding:10px 0;border-bottom:1px dashed #cbd5e1;gap:12px;flex-wrap:wrap}.result-row:last-child{border-bottom:none}.result-row .lbl{font-weight:600;color:var(--ink-soft);font-size:14px}.result-row .val{font-weight:500;color:var(--ink);text-align:right;word-break:break-word;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:14px}.result-big{font-size:28px;font-weight:700;color:var(--primary);margin:8px 0}.result-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}.formula-box{background:#fff;border:1px solid var(--border);border-left:4px solid var(--accent);border-radius:8px;padding:14px 16px;margin:14px 0;font-family:Georgia,serif;font-size:16px;overflow-x:auto;line-height:1.8}.steps-box{background:#fefce8;border:1px solid #fde68a;border-radius:8px;padding:14px 16px;margin:14px 0}.steps-box h4{margin:0 0 10px;color:#a16207}.example-box{background:#ecfdf5;border:1px solid #a7f3d0;border-radius:8px;padding:14px 16px;margin:14px 0}.warn-box{background:#fef2f2;border:1px solid #fecaca;border-radius:8px;padding:12px 14px;margin:12px 0;color:#991b1b;font-size:14px}.info-box{background:#eff6ff;border:1px solid #bfdbfe;border-radius:8px;padding:12px 14px;margin:12px 0;color:#1e40af;font-size:14px}
.data-table{width:100%;border-collapse:collapse;margin:10px 0;font-size:13px}.data-table th,.data-table td{border:1px solid var(--border);padding:7px 10px;text-align:right;font-family:ui-monospace,monospace}.data-table th{background:#f1f5f9;font-weight:600;color:var(--ink-soft);text-align:center}.data-table tbody tr:nth-child(even){background:#f8fafc}.table-wrap{max-height:320px;overflow:auto;border:1px solid var(--border);border-radius:8px;margin:10px 0}.svg-wrap{background:#fff;border:1px solid var(--border);border-radius:8px;padding:10px;margin:14px 0;overflow:hidden;text-align:center}.svg-wrap svg{max-width:100%;height:auto;display:block;margin:0 auto}.ph-scale{height:24px;border-radius:999px;background:linear-gradient(90deg,#ef4444,#f59e0b,#22c55e,#06b6d4,#3b82f6,#7c3aed);position:relative;margin:16px 0}.ph-marker{position:absolute;top:-7px;width:4px;height:38px;border-radius:2px;background:#111827}.periodic-grid{display:grid;grid-template-columns:repeat(18,minmax(34px,1fr));gap:4px}.element-tile{min-height:48px;border:1px solid var(--border);border-radius:6px;background:#fff;padding:4px;text-align:center;cursor:pointer}.element-tile:hover,.element-tile.active{outline:2px solid var(--primary)}.element-tile .z{font-size:10px;color:var(--muted);display:block}.element-tile .sym{font-weight:800;color:var(--ink);display:block}.element-tile .nm{font-size:9px;color:var(--muted);display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.flashcard{min-height:180px;border:1px solid var(--border);border-radius:var(--radius);display:flex;align-items:center;justify-content:center;text-align:center;padding:20px;background:#f8fafc;font-size:26px;font-weight:800;cursor:pointer}.sig-highlight span{display:inline-block;padding:2px 4px;margin:1px;border-radius:4px}.sig-highlight .yes{background:#dcfce7;color:#166534}.sig-highlight .no{background:#f1f5f9;color:#64748b}
details{background:#fff;border:1px solid var(--border);border-radius:8px;padding:14px 16px;margin:8px 0}details[open]{box-shadow:var(--shadow)}summary{font-weight:600;cursor:pointer;color:var(--ink);outline:none;list-style:none;position:relative;padding-right:20px}summary::-webkit-details-marker{display:none}summary:after{content:"+";position:absolute;right:0;top:0;color:var(--primary);font-weight:700;font-size:20px;line-height:1}details[open] summary:after{content:"-"}.pills{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0}.pills a{display:inline-block;background:#f1f5f9;color:var(--ink);padding:6px 14px;border-radius:999px;font-size:13px;border:1px solid var(--border)}.pills a:hover{background:var(--primary);color:#fff;text-decoration:none;border-color:var(--primary)}
.site-footer{background:#0f172a;color:#cbd5e1;margin-top:60px;padding:40px 20px 20px}.footer-grid{max-width:1200px;margin:0 auto;display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:30px}.footer-col h4{color:#fff;font-size:15px;margin:0 0 12px;font-weight:600}.footer-col ul{list-style:none;padding:0;margin:0}.footer-col li{margin:6px 0}.footer-col a{color:#cbd5e1;font-size:14px}.footer-col a:hover{color:#fff}.footer-bottom{max-width:1200px;margin:30px auto 0;padding-top:20px;border-top:1px solid #1e293b;text-align:center;font-size:13px;color:#94a3b8}.footer-grid .footer-col:nth-child(2) ul{display:grid;grid-template-columns:1fr 1fr;column-gap:14px}.footer-grid .footer-col:nth-child(2) li{margin:4px 0;line-height:1.3}
.hidden{display:none!important}.text-muted{color:var(--muted)}.note{font-size:13px;color:var(--muted);margin-top:6px}
@media(max-width:820px){.nav-toggle{display:block}.nav-menu{display:none;flex-direction:column;width:100%;background:#fff;border-top:1px solid var(--border);padding:10px 0;margin-top:14px}.nav-menu.open{display:flex}.nav-menu>li>a,.nav-menu>li>span{padding:10px 16px}.dropdown{position:static;display:none;box-shadow:none;border:none;padding:0 0 0 16px;background:transparent}.nav-menu>li.open .dropdown{display:block}header .nav-menu>li:first-child .dropdown,header .dropdown{min-width:0;grid-template-columns:1fr;padding:0 0 0 16px;left:0;right:auto}.footer-grid .footer-col:nth-child(2) ul{grid-template-columns:1fr}.periodic-grid{grid-template-columns:repeat(4,1fr)}}@media(max-width:640px){.chem-hero h1{font-size:1.7rem}.chem-hero p{font-size:1rem}h1{font-size:24px}h2{font-size:19px}.field-row{grid-template-columns:1fr}.tool-grid{grid-template-columns:1fr}.result-big{font-size:22px}.tool-card{padding:16px}}@media print{.site-header,.site-footer,.btn-row,.result-actions,.chem-search,.nav-toggle,.pills{display:none!important}body{background:#fff;color:#000}.tool-card,.result-card,.formula-box{box-shadow:none;border:1px solid #999}a{color:#000;text-decoration:underline}}

/* Interactive periodic table */
.periodic-shell{display:grid;gap:16px}
.periodic-scroll{overflow-x:auto;padding:4px 2px 12px}
.periodic-grid{min-width:1060px;display:grid;grid-template-columns:repeat(18,56px);grid-template-rows:repeat(9,64px);gap:6px;align-items:stretch}
.periodic-grid.compact{min-width:0;grid-template-columns:repeat(auto-fill,minmax(76px,1fr));grid-template-rows:auto}
.element-tile{position:relative;min-height:64px;border:1px solid rgba(15,23,42,.12);border-radius:8px;background:#fff;padding:5px 4px;text-align:center;cursor:pointer;box-shadow:0 1px 2px rgba(15,23,42,.05);transition:transform .12s ease,box-shadow .12s ease,outline-color .12s ease}
.element-tile:hover,.element-tile.active{transform:translateY(-2px);box-shadow:0 8px 18px rgba(15,23,42,.12);outline:2px solid var(--primary);z-index:2}
.element-tile .z{font-size:10px;color:#475569;display:block;line-height:1;text-align:left}
.element-tile .sym{font-size:18px;font-weight:800;color:#0f172a;display:block;line-height:1.1;margin-top:3px}
.element-tile .nm{font-size:9px;color:#334155;display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-top:2px}
.element-tile .mass{font-size:8px;color:#64748b;display:block;line-height:1.1}
.series-label{align-self:center;justify-self:end;color:#64748b;font-size:12px;font-weight:700;padding-right:8px}
.lan-label{grid-column:1 / 4;grid-row:8}.act-label{grid-column:1 / 4;grid-row:9}
.periodic-legend{display:flex;flex-wrap:wrap;gap:8px 12px;padding:10px 12px;background:#f8fafc;border:1px solid var(--border);border-radius:10px}
.periodic-legend span{display:inline-flex;align-items:center;gap:6px;font-size:12px;color:#475569}
.periodic-legend i{width:13px;height:13px;border-radius:4px;display:inline-block;border:1px solid rgba(15,23,42,.12)}
.cat-alkali-metal{background:#fee2e2}.cat-alkaline-earth-metal{background:#ffedd5}.cat-transition-metal{background:#dbeafe}.cat-post-transition-metal{background:#e0f2fe}.cat-metalloid{background:#dcfce7}.cat-nonmetal{background:#fef9c3}.cat-halogen{background:#ede9fe}.cat-noble-gas{background:#fce7f3}.cat-lanthanide{background:#ccfbf1}.cat-actinide{background:#fae8ff}
.element-detail-head{display:flex;align-items:center;gap:14px;padding:14px;border-radius:10px;border:1px solid rgba(15,23,42,.10);margin-bottom:12px}
.element-detail-head strong{font-size:34px;line-height:1;color:#0f172a}.element-detail-head h3{margin:0}.element-detail-head p{margin:0;color:#475569;text-transform:capitalize}
.detail-z{display:block;font-size:12px;color:#475569;font-weight:700}
@media(max-width:820px){.periodic-scroll{margin-left:-16px;margin-right:-16px;padding-left:16px}.periodic-grid{min-width:980px;grid-template-columns:repeat(18,52px);grid-template-rows:repeat(9,62px);gap:5px}.periodic-grid.compact{min-width:0;grid-template-columns:repeat(auto-fill,minmax(70px,1fr))}.element-tile .sym{font-size:16px}}