:root{color-scheme:light;--bg: #d3dee2ff;--surface: #f7fbfcff;--surface-muted: #e8eff1ff;--text: #14252aff;--muted: #4e6268ff;--border: #a9c2c9ff;--accent: #007e8aff;--accent-strong: #00626cff;--accent-hover: #004750ff;--highlight: #ffcc00ff;--header: #007e8aff;--header-text: #ffffffff;--header-muted: #f4fafaff;--success: #1f6b5f;--success-bg: #e2f1ea;--success-border: #a7cbc1;--danger: #b3261e;--danger-bg: #f5e3e0;--danger-border: #e2b3ac;--radius: 12px;--shadow: 0 1px 2px rgba(20, 37, 42, .05), 0 10px 28px rgba(20, 37, 42, .07);--font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif}*{box-sizing:border-box}[hidden]{display:none!important}html{scroll-behavior:smooth}body{display:flex;flex-direction:column;min-height:100vh;margin:0;background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.5}::selection{background:var(--highlight);color:var(--text)}a{color:var(--accent-strong);text-decoration-thickness:1px;text-underline-offset:3px}a:hover{color:var(--accent-hover)}.skip-link{position:absolute;left:12px;top:-56px;z-index:100;padding:8px 12px;border-radius:0 0 8px 8px;background:var(--accent);color:#fff;font-weight:700;text-decoration:none;transition:top .15s ease}.skip-link:focus{top:0;color:#fff}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.wrap{width:min(1180px,calc(100% - 32px));margin-inline:auto}.site-header{position:sticky;top:0;z-index:20;padding:10px 0 9px;border-bottom:2px solid var(--highlight);background:var(--header);color:var(--header-text)}.header-inner{display:flex;align-items:center;justify-content:space-between;gap:24px;min-height:64px}.brand{display:flex;align-items:center;gap:12px;color:var(--header-text);text-decoration:none;white-space:nowrap}.brand .brand-mark{height:64px;width:auto;display:block}.brand-text{display:flex;flex-direction:column;align-items:center;line-height:1.05}.brand-text strong{font-size:2rem;font-weight:700;letter-spacing:-.03em}.brand-text>span{margin-top:.25rem;font-size:1rem;font-weight:600;letter-spacing:.04em}.brand:hover{color:var(--header-text)}.brand:focus-visible{border-radius:2px;outline:2px solid var(--header-text);outline-offset:4px}nav{display:flex;gap:6px}nav a{padding:7px 10px;border-radius:999px;color:var(--header-muted);font-size:14px;font-weight:600;text-decoration:none}nav a:hover{background:#ffffff14;color:var(--header-text)}nav a:focus-visible{outline:2px solid var(--header-text);outline-offset:1px}nav a[aria-current=page]{background:var(--highlight);color:var(--text)}nav a[aria-current=page]:focus-visible{outline-color:var(--text)}main{flex:1;padding-bottom:24px}.section{scroll-margin-top:84px;padding:48px 0}.section+.section{border-top:1px solid var(--border)}.section-intro{max-width:760px}.eyebrow{margin:0 0 6px;color:var(--accent-strong);font-size:12px;font-weight:700;letter-spacing:.12em;text-transform:uppercase}h1,h2{margin:0;line-height:1.15;letter-spacing:-.02em}h1{font-size:clamp(28px,4vw,40px)}h2{font-size:clamp(24px,3vw,32px)}.section-intro>p:last-child{max-width:70ch;margin:10px 0 0;color:var(--muted)}.pse-search{width:100%;max-width:540px;margin:22px auto 0}.search-field{position:relative}.pse-search .search-field input{width:100%;padding:12px 44px 12px 16px;font-size:15px}.search-icon{position:absolute;top:50%;right:15px;width:18px;height:18px;color:var(--muted);opacity:.7;pointer-events:none;transform:translateY(-50%)}.search-meta{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:6px 12px;margin-top:8px}.search-status{min-height:20px;margin:0;color:var(--muted);font-size:12px;line-height:1.4;text-align:center}.search-reset{padding:0;border:0;background:none;color:var(--accent-strong);cursor:pointer;font:inherit;font-size:12px;font-weight:600}.search-reset:hover{color:var(--accent-hover);text-decoration:underline}.search-reset:focus-visible{border-radius:2px;outline:2px solid var(--accent);outline-offset:3px}.legend{display:flex;flex-wrap:wrap;gap:8px 16px;margin:24px 0 12px;padding:0;list-style:none}.legend-item{display:flex;align-items:center;gap:7px;color:var(--muted);font-size:12px}.legend-swatch{width:12px;height:12px;border:1px solid var(--category-color);border-radius:3px;background:var(--category-bg)}.scroll-hint{display:none;margin:0 0 8px;color:var(--muted);font-size:12px}.pse-scroll{overflow-x:auto;padding:4px 0 12px}.pse-grid{display:grid;grid-template-columns:repeat(18,minmax(50px,1fr));grid-template-rows:repeat(7,minmax(58px,auto)) 10px repeat(2,minmax(58px,auto));grid-auto-rows:minmax(58px,auto);gap:4px;min-width:1000px;padding:12px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.element-cell{--category-color: #64748b;--category-bg: #f7f9fb;position:relative;display:flex;min-width:0;flex-direction:column;align-items:center;justify-content:center;padding:4px 2px 3px;border:1px solid var(--border);border-top:3px solid var(--category-color);border-radius:7px;appearance:none;background:var(--category-bg);color:var(--text);font:inherit;cursor:pointer;transition:transform .12s ease,box-shadow .12s ease,border-color .12s ease}.element-cell:hover{transform:translateY(-1px);border-color:var(--category-color);box-shadow:0 4px 10px #0f172a1a}.element-cell:focus-visible{z-index:2;outline:3px solid var(--accent);outline-offset:2px}.element-cell[aria-pressed=true]{border-color:var(--accent);box-shadow:inset 0 0 0 2px var(--accent),0 4px 10px #0f172a1a}.element-cell.is-dimmed{opacity:.22;pointer-events:none;filter:grayscale(.6)}.element-z{align-self:flex-start;margin-left:3px;color:var(--muted);font-size:10px;line-height:1}.element-symbol{font-size:clamp(15px,1.3vw,18px);font-weight:700;letter-spacing:-.02em;line-height:1.1}.element-name{max-width:100%;overflow:hidden;color:var(--muted);font-size:9px;line-height:1.1;text-overflow:ellipsis;white-space:nowrap}.pse-spacer{height:10px}.series-label{display:flex;align-items:center;justify-content:flex-end;overflow:hidden;padding-right:8px;color:var(--muted);font-size:10px;font-weight:700;letter-spacing:.04em;text-overflow:ellipsis;text-transform:uppercase;white-space:nowrap}.element-details{margin-top:8px;padding:20px 22px;border:1px solid var(--border);border-left:4px solid var(--category-color, var(--accent));border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.detail-header{display:flex;align-items:center;gap:16px}.detail-symbol{display:grid;flex:none;place-items:center;width:72px;height:72px;border:1px solid var(--category-color, var(--border));border-radius:12px;background:var(--category-bg, var(--surface-muted));color:var(--text);font-size:30px;font-weight:700;letter-spacing:-.03em}.detail-z{margin:0;color:var(--muted);font-size:12px;letter-spacing:.08em;text-transform:uppercase}.detail-name{margin:2px 0 6px;font-size:28px;line-height:1.1}.category-badge{display:inline-block;padding:2px 8px;border:1px solid var(--category-color);border-radius:999px;background:var(--category-bg);color:var(--category-color);font-size:12px;font-weight:700}.detail-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px 24px;margin:20px 0 0}.detail-item{padding-top:8px;border-top:1px solid var(--border)}.detail-item dt{color:var(--muted);font-size:11px;letter-spacing:.07em;text-transform:uppercase}.detail-item dd{margin:3px 0 0;font-weight:600}.detail-notes{margin-top:16px;color:var(--muted);font-size:13px}.detail-notes p{margin:4px 0 0}.detail-notes:empty{display:none}.pse-details{display:grid;grid-template-columns:112px minmax(0,1fr);grid-template-rows:auto auto;gap:10px 20px;align-items:stretch;padding:18px 20px}.pse-details .detail-symbol{grid-row:1 / span 2;width:auto;height:auto;min-height:116px;border-radius:14px;font-size:48px}.pse-details .detail-header{display:block}.pse-details .detail-z{font-size:11px}.pse-details .detail-top{display:grid;grid-column:2;grid-template-columns:minmax(160px,.75fr) minmax(0,2fr);align-items:center;gap:24px}.pse-details .detail-heading{display:flex;flex-wrap:wrap;align-items:center;gap:10px;margin-top:2px}.pse-details .detail-name{margin:0;font-size:30px}.pse-details .detail-facts{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px 16px;margin:0}.pse-details .detail-item{padding-top:6px;border-top:1px solid var(--border)}.pse-details .detail-item dt{font-size:10px;letter-spacing:.06em}.pse-details .detail-item dd{margin-top:2px;font-size:14px;line-height:1.3}.pse-details .detail-config{display:block;grid-column:2;margin:0;padding-top:8px;border-top:1px solid var(--border)}.pse-details .detail-config .detail-item{display:flex;align-items:baseline;gap:12px;padding-top:0;border-top:0}.pse-details .detail-config dt{flex:0 0 auto}.pse-details .detail-config dd{margin:0}.pse-details .detail-notes{grid-column:1 / -1;margin-top:0}.pse-bottom{display:grid;gap:12px;margin-top:8px}.pse-bottom .element-details{margin-top:0}.pse-calculator{display:flex;min-width:0;flex-direction:column;padding:14px 16px;border:1px solid var(--border);border-top:3px solid var(--highlight);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.pse-calculator h2{color:var(--muted);font-size:11px;font-weight:400;line-height:1.5;letter-spacing:.08em;text-transform:uppercase}.quick-calculator-form{margin-top:10px}.pse-calculator .input-row{gap:8px}.pse-calculator input[type=text]{flex-basis:0;padding:9px 10px;font-size:14px}.pse-calculator button[type=submit]{padding:9px 14px;font-size:14px;white-space:nowrap}.pse-calculator .mass-result{margin-top:6px}.pse-calculator .mass-result:empty{display:none}.pse-calculator .result-card{padding:6px 10px;border:0;background:var(--surface-muted);box-shadow:none}.pse-calculator .result-label{font-size:10px;line-height:1.2}.pse-calculator .result-total{margin:1px 0 0;font-size:24px;line-height:1.05;letter-spacing:-.02em}.pse-calculator .result-total span{font-size:12px}.pse-calculator .form-error{padding:9px 11px;font-size:13px}.calculator-card{margin-top:24px;padding:20px 22px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.calculator-card label{display:block;margin-bottom:8px;font-weight:700}.input-row{display:flex;flex-wrap:wrap;gap:10px}input[type=text],input[type=search]{flex:1 1 260px;min-width:0;padding:11px 13px;border:1px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text);font:inherit}input[type=search]::-webkit-search-cancel-button{appearance:none}input[type=text]:focus,input[type=search]:focus{border-color:var(--accent);outline:3px solid var(--accent);outline-offset:1px}input[aria-invalid=true]{border-color:var(--danger)}.button,button[type=submit]{padding:11px 20px;border:1px solid var(--accent);border-radius:8px;background:var(--accent);color:#fff;cursor:pointer;font:inherit;font-weight:700}.button:hover,button[type=submit]:hover{border-color:var(--accent-strong);background:var(--accent-strong)}.button:focus-visible,button[type=submit]:focus-visible{outline:3px solid var(--accent);outline-offset:2px}.button-secondary{border-color:var(--border);background:var(--surface);color:var(--text)}.button-secondary:hover{border-color:var(--accent);background:var(--surface-muted);color:var(--text)}.hint{margin:10px 0 0;color:var(--muted);font-size:13px}.mass-result{margin-top:18px}.result-placeholder{margin:0;color:var(--muted)}.result-card{padding:20px 22px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.result-label{margin:0;color:var(--muted);font-size:14px}.result-label strong{color:var(--text)}.result-total{margin:4px 0 18px;font-size:clamp(30px,5vw,44px);letter-spacing:-.03em;line-height:1.1}.result-total span{color:var(--muted);font-size:16px;font-weight:600;letter-spacing:0}.table-scroll{overflow-x:auto}.composition-table{width:100%;border-collapse:collapse;font-size:14px}.composition-table th,.composition-table td{padding:9px 10px;border-bottom:1px solid var(--border);text-align:left;white-space:nowrap}.composition-table thead th{background:var(--surface-muted);color:var(--muted);font-size:11px;letter-spacing:.06em;text-transform:uppercase}.composition-table tbody th{font-weight:600}.composition-table th:nth-child(2),.composition-table td:nth-child(2),.composition-table th:nth-child(3),.composition-table td:nth-child(3),.composition-table th:nth-child(4),.composition-table td:nth-child(4){text-align:right}.form-error{margin:0;padding:12px 14px;border:1px solid var(--danger-border);border-radius:8px;background:var(--danger-bg);color:var(--danger);font-weight:600}.notice{margin:0 0 20px;padding:12px 14px;border:1px solid var(--danger-border);border-radius:8px;background:var(--danger-bg);color:var(--danger)}.site-footer{padding:24px 0 28px;background:var(--header);color:var(--header-muted);font-size:12px}.site-footer a{color:var(--header-muted)}.site-footer a:hover{color:var(--header-text)}.site-footer p{margin:0}.footer-inner{display:grid;grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);align-items:center;gap:14px 24px}.footer-left{justify-self:start;text-align:left}.footer-copy{margin:0;text-align:center}.footer-legal{display:flex;flex-wrap:wrap;justify-content:flex-end;gap:10px 18px}.footer-legal a{font-weight:700}.legal-copy{max-width:820px}.legal-copy p{margin-top:12px}.legal-copy p:first-child{margin-top:20px}.legal-copy h2{margin-top:28px;font-size:20px}.legal-copy ul{margin:12px 0 0;padding-left:22px}.legal-copy li+li{margin-top:6px}.legal-update{color:var(--muted);font-size:13px}[data-category=alkali]{--category-color: #b23a48;--category-bg: #fbeaec}[data-category=alkaline]{--category-color: #a34a08;--category-bg: #fdf0e3}[data-category=transition]{--category-color: #2563a8;--category-bg: #eaf2fb}[data-category=post-transition]{--category-color: #0f766e;--category-bg: #e6f6f2}[data-category=metalloid]{--category-color: #6d4fc4;--category-bg: #f1edfc}[data-category=nonmetal]{--category-color: #2f7d32;--category-bg: #eaf6e8}[data-category=halogen]{--category-color: #a16207;--category-bg: #fdf6dc}[data-category=noble]{--category-color: #7e3a9e;--category-bg: #f6ecfb}[data-category=lanthanide]{--category-color: #b03a6b;--category-bg: #fcecf2}[data-category=actinide]{--category-color: #8e2f4f;--category-bg: #f9e8ee}.isotope-picker{display:flex;flex-wrap:wrap;align-items:flex-end;gap:16px 24px;margin-top:24px;padding:16px 18px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.isotope-picker>div{flex:1 1 320px;max-width:440px}.isotope-picker label{display:block;margin-bottom:7px;font-weight:700}.isotope-picker select{width:100%;padding:11px 13px;border:1px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text);font:inherit}.isotope-picker select:focus-visible{border-color:var(--accent);outline:3px solid var(--accent);outline-offset:1px}.isotope-picker .hint{flex:1 1 320px;max-width:58ch;margin:0 0 2px}.isotope-summary{margin-top:18px}.isotope-card{margin-top:18px;padding:20px 22px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.isotope-card-header{display:flex;flex-wrap:wrap;align-items:flex-end;justify-content:space-between;gap:8px 20px;margin-bottom:12px}.isotope-card-header h2{font-size:clamp(20px,2.5vw,26px)}.isotope-table-meta{margin:4px 0 0;color:var(--muted);font-size:13px}.isotope-table-count{margin:0;color:var(--muted);font-size:13px;font-weight:700}.isotope-table-scroll{border:1px solid var(--border);border-radius:8px}.isotope-table-scroll:focus-visible{outline:3px solid var(--accent);outline-offset:2px}.isotope-table{width:100%;min-width:760px;border-collapse:collapse;font-size:14px}.isotope-table th,.isotope-table td{padding:9px 10px;border-bottom:1px solid var(--border);text-align:left;white-space:nowrap}.isotope-table thead th{background:var(--surface-muted);color:var(--muted);font-size:11px;letter-spacing:.06em;text-transform:uppercase}.isotope-table tbody th{font-weight:700;font-variant-numeric:tabular-nums}.isotope-table tbody td{font-variant-numeric:tabular-nums}.isotope-table tbody tr:hover{background:var(--surface-muted)}.isotope-table tbody tr:last-child th,.isotope-table tbody tr:last-child td{border-bottom:0}.isotope-table tbody tr.is-natural th{color:var(--accent-strong)}.status-badge{display:inline-block;padding:1px 7px;border:1px solid var(--border);border-radius:999px;font-size:12px;font-weight:700}.status-badge.is-stable{border-color:var(--success-border);background:var(--success-bg);color:var(--success)}.status-badge.is-unknown{background:var(--surface-muted);color:var(--muted)}.isotope-note{margin:12px 0 0;color:var(--muted);font-size:12px}.quiz-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:24px;align-items:start;margin-top:28px}.quiz-card,.quiz-sidebar{padding:26px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow)}.quiz-sidebar{position:sticky;top:84px}.quiz-meta{display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px 16px;color:var(--muted);font-size:12px;font-weight:700;letter-spacing:.06em;text-transform:uppercase}.quiz-meter{height:8px;margin-top:10px;overflow:hidden;border-radius:999px;background:var(--surface-muted)}.quiz-meter span{display:block;width:0;height:100%;border-radius:inherit;background:var(--accent);transition:width .2s ease}.quiz-prompt{margin:28px 0 4px;font-size:clamp(42px,7vw,64px);font-weight:800;letter-spacing:-.04em;line-height:1}.quiz-question{margin:0 0 20px;font-size:18px;line-height:1.4}.quiz-options{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.quiz-option{padding:14px 16px;border:1px solid var(--border);border-radius:10px;background:var(--surface);color:var(--text);cursor:pointer;font:inherit;font-weight:600;text-align:left}.quiz-option:hover:not(:disabled){border-color:var(--accent);background:var(--surface-muted)}.quiz-option:focus-visible{outline:3px solid var(--accent);outline-offset:2px}.quiz-option:disabled{cursor:default;opacity:.65}.quiz-option.is-correct{border-color:var(--success);background:var(--success-bg)}.quiz-option.is-wrong{border-color:var(--danger);background:var(--danger-bg)}.quiz-option.is-correct:disabled,.quiz-option.is-wrong:disabled{opacity:1}.quiz-feedback{min-height:24px;margin:16px 0 0;font-weight:600}.quiz-feedback.is-correct{color:var(--success)}.quiz-feedback.is-wrong{color:var(--danger)}#quiz-next{margin-top:16px}.quiz-result{margin-top:20px;padding:18px;border-radius:10px;background:var(--surface-muted)}.quiz-result p{margin:0;font-weight:600}.quiz-result .button{margin-top:14px}.quiz-sidebar h2{font-size:18px}.quiz-stats{display:grid;gap:10px;margin:18px 0 20px}.quiz-stats div{display:flex;align-items:baseline;justify-content:space-between;gap:12px;padding-bottom:8px;border-bottom:1px solid var(--border)}.quiz-stats dt{color:var(--muted);font-size:13px}.quiz-stats dd{margin:0;font-weight:700}.quiz-sidebar .button{width:100%}@media(min-width:1040px){.pse-section{padding-top:24px}.pse-stage{position:relative}.pse-bottom{grid-template-columns:minmax(0,2fr) minmax(300px,1fr);gap:16px;align-items:stretch}.pse-tools{position:absolute;top:13px;right:13px;left:13px;z-index:3;display:grid;grid-template-columns:repeat(18,minmax(0,1fr));grid-template-rows:58px 58px 58px;gap:4px;pointer-events:none}.pse-tools>*{pointer-events:auto}.pse-intro{grid-row:1;grid-column:3 / span 14;display:flex;align-items:center;gap:20px;max-width:none}.pse-intro>div{flex:0 0 auto}.pse-intro .eyebrow{margin-bottom:2px;font-size:10px}.pse-intro h1{font-size:clamp(22px,2vw,28px);line-height:1.1;white-space:nowrap}.pse-intro>p:last-child{max-width:56ch;margin:0;padding-left:20px;border-left:1px solid var(--border);font-size:12.5px;line-height:1.35}.pse-search{grid-row:2 / span 2;grid-column:3 / span 9;align-self:center;justify-self:center;width:100%;max-width:540px;margin:0}.pse-search .search-field input{padding-block:10px}.pse-section .pse-scroll{padding-top:0}}@media(max-width:900px){.quiz-layout{grid-template-columns:1fr}.quiz-sidebar{position:static}.footer-inner{grid-template-columns:1fr;gap:8px}.footer-left,.footer-copy{justify-self:center;text-align:center}.footer-legal{justify-content:center}}@media(max-width:760px){.wrap{width:min(100% - 20px,1180px)}.header-inner{min-height:58px}nav{gap:14px}.section{padding:32px 0}.quiz-layout{gap:16px;margin-top:20px}.isotope-picker,.isotope-card{padding:16px}.isotope-scroll-hint{display:block}.quiz-card,.quiz-sidebar{padding:18px}.quiz-options{grid-template-columns:1fr}.quiz-prompt{font-size:clamp(36px,12vw,48px)}.pse-grid{grid-template-columns:repeat(18,46px);grid-template-rows:repeat(7,minmax(52px,auto)) 10px repeat(2,minmax(52px,auto));grid-auto-rows:minmax(52px,auto);min-width:920px}.scroll-hint{display:block}.detail-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.element-cell{padding:3px 1px}.element-name{display:none}.element-symbol{font-size:14px}.detail-header{align-items:flex-start}.detail-symbol{width:60px;height:60px;font-size:24px}.detail-name{font-size:24px}.pse-details{grid-template-columns:78px minmax(0,1fr);gap:10px 14px;padding:16px}.pse-details .detail-symbol{width:auto;height:auto;min-height:100%;font-size:36px}.pse-details .detail-top{grid-template-columns:1fr;gap:10px}.pse-details .detail-name{font-size:24px}.pse-details .detail-facts{grid-template-columns:repeat(2,minmax(0,1fr))}.pse-details .detail-config .detail-item{display:block}.pse-details .detail-config dd{margin-top:2px}.composition-table,.isotope-table{font-size:13px}}@media(max-width:600px){.header-inner{flex-wrap:wrap;gap:6px 16px;padding:10px 0}.brand{gap:10px}.brand .brand-mark{height:48px}.brand-text strong{font-size:1.65rem}.brand-text>span{margin-top:.15rem;font-size:.8rem}nav{width:100%;gap:2px}nav a{padding:7px 8px}}@media(max-width:480px){.isotope-picker,.isotope-card{padding:14px}.quiz-card,.quiz-sidebar{padding:16px}.isotope-table{font-size:12px}.isotope-table th,.isotope-table td{padding:8px 7px}.quiz-option{padding:12px 14px}.composition-table{table-layout:fixed;font-size:12px}.composition-table th,.composition-table td{padding:8px 5px;white-space:normal}.composition-table thead th{font-size:10px;letter-spacing:.02em}.composition-table th:first-child,.composition-table td:first-child{width:40%}.composition-table th:nth-child(2),.composition-table td:nth-child(2){width:15%}.composition-table th:nth-child(3),.composition-table td:nth-child(3){width:25%}.composition-table th:nth-child(4),.composition-table td:nth-child(4){width:20%}.detail-grid{grid-template-columns:1fr}.isotope-summary .detail-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;transition:none!important}}@media print{@page{size:A4 portrait;margin:12mm}body{display:block;min-height:auto;background:#fff;color:#000;font-size:11pt}.wrap{width:auto;margin:0}main{padding:0}.site-header,.site-footer,.skip-link,.search-panel,.isotope-picker,.pse-calculator,.scroll-hint,.quiz-sidebar,.result-placeholder,#quiz-next{display:none!important}.pse-bottom{display:block}.pse-tools{position:static;display:block}.pse-intro{display:block;max-width:760px}.pse-intro h1{font-size:28px}.pse-intro>p:last-child{max-width:70ch;margin:10px 0 0;padding:0;border:0;font-size:11pt;line-height:1.5}.section{padding:0;border:0;scroll-margin-top:0}.section+.section{margin-top:10mm;padding-top:6mm;border-top:1px solid #999999}.section-intro>p:last-child,.hint,.isotope-table-meta,.isotope-table-count,.isotope-note,.detail-notes{color:#333}.pse-scroll,.table-scroll,.isotope-table-scroll{overflow:visible;padding:0;border-color:#999}.pse-grid{grid-template-columns:repeat(18,minmax(0,1fr));grid-template-rows:repeat(7,30px) 8px repeat(2,30px);gap:2px;min-width:0;padding:4px;border-color:#999;box-shadow:none}.series-label{padding-right:4px;font-size:9px;letter-spacing:0}.element-cell{min-height:0;padding:1px;border-color:#aaa;border-top-width:2px;border-radius:3px;background:#fff;box-shadow:none;transform:none}.element-cell.is-dimmed{opacity:1;filter:none;pointer-events:auto}.element-cell[aria-pressed=true]{outline:2px solid #000000;outline-offset:1px;box-shadow:none}.element-name{display:none}.element-symbol{font-size:10px}.element-z{font-size:7px}.element-details,.isotope-card,.calculator-card,.result-card,.quiz-card,.quiz-result{border-color:#999;box-shadow:none}.element-details{border-left-width:3px;break-inside:avoid}.detail-symbol{width:48px;height:48px;font-size:20px}.detail-name{font-size:20px}.detail-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:8px 16px;margin-top:12px}.pse-details{grid-template-columns:82px minmax(0,1fr);gap:6px 12px;padding:12px}.pse-details .detail-symbol{width:auto;height:auto;min-height:88px;font-size:30px}.pse-details .detail-top{grid-template-columns:minmax(140px,.7fr) minmax(0,2fr);gap:14px}.pse-details .detail-name{font-size:18px}.pse-details .detail-facts{gap:6px 10px}.pse-details .detail-config{padding-top:6px}.category-badge,.status-badge{border-color:#555;background:#fff;color:#000}.isotope-card{padding:12px}.isotope-table{min-width:0;font-size:9pt}.isotope-table thead{display:table-header-group}.isotope-table th,.isotope-table td{padding:5px 6px;border-color:#999;white-space:normal}.isotope-table thead th{background:#fff;color:#000}.isotope-table tbody tr{break-inside:avoid}.isotope-table tbody tr:hover{background:transparent}.status-badge.is-stable,.status-badge.is-unknown{border-color:#555;background:#fff;color:#000}.quiz-card{padding:0;border:0}.quiz-option{border-color:#999;break-inside:avoid}.quiz-option.is-correct{border:2px solid #000000;background:#fff}.quiz-option.is-wrong{border:2px dashed #000000;background:#fff;text-decoration:line-through}.quiz-meter{border:1px solid #555555;background:#fff}.quiz-meter span{background:#000}.quiz-result{background:#fff}a{color:#000;text-decoration:none}h1,h2{break-after:avoid}}