:root{color-scheme:light;--page-bg: #eef4f3;--page-wash: rgba(255, 255, 255, .75);--text: #152b2c;--heading: #142f31;--muted: #486466;--label: #526b6d;--accent: #197b76;--accent-strong: #116c68;--accent-soft: #e7f2ef;--accent-text: #276560;--panel: rgba(255, 255, 255, .96);--panel-solid: #ffffff;--panel-subtle: #f3faf8;--panel-muted: #edf5f4;--border: #cfdddb;--border-strong: #bfd0cf;--shadow: rgba(30, 63, 65, .08);--button-secondary: #243d4a;--warning-bg: #fff8e7;--warning-border: #d8c595;--warning-strong: #bd8425;--warning-text: #543d12;--success-bg: #edf9f2;--success-border: #a9d4c3;--success-text: #173c2c;--error-bg: #fff0ed;--error-border: #e5b8b2;--error-text: #562119;--info-bg: #f4f8fa;--info-border: #cbd8e1;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:var(--page-bg);color:var(--text);font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased}[data-theme=dark]{color-scheme:dark;--page-bg: #071112;--page-wash: rgba(16, 38, 40, .72);--text: #e8f3f1;--heading: #f4fbfa;--muted: #adc4c4;--label: #b0c6c6;--accent: #55c8bd;--accent-strong: #2fb2a6;--accent-soft: #123937;--accent-text: #96e7df;--panel: rgba(13, 29, 31, .96);--panel-solid: #102426;--panel-subtle: #122d2f;--panel-muted: #102b2d;--border: #244548;--border-strong: #355f62;--shadow: rgba(0, 0, 0, .28);--button-secondary: #365469;--warning-bg: #2c2414;--warning-border: #7b642f;--warning-strong: #d4a23b;--warning-text: #f4dfae;--success-bg: #123125;--success-border: #347a61;--success-text: #c5f1df;--error-bg: #351b1b;--error-border: #8b4a44;--error-text: #ffd1cb;--info-bg: #152a35;--info-border: #385463}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh;background:linear-gradient(180deg,var(--page-wash),rgba(238,244,243,0)),var(--page-bg)}button,input,select{font:inherit}main{width:min(1180px,calc(100% - 32px));margin:0 auto;padding:32px 0 48px}.app-header{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;padding:24px 0 18px}.eyebrow{margin:0 0 8px;color:var(--accent-text);font-size:.9rem;font-weight:800;text-transform:uppercase}h1,h2,p{margin-top:0}h1{margin-bottom:10px;color:var(--heading);font-size:clamp(2rem,5vw,4.1rem);line-height:1}.app-header p:last-child{margin-bottom:0;max-width:680px;color:var(--muted);font-size:1.15rem}.header-actions{display:flex;flex:0 0 auto;flex-wrap:wrap;justify-content:flex-end;gap:10px}.header-badge,.disclaimer,.formula-line,.feedback-status{display:flex;align-items:center;gap:10px}.header-badge{flex:0 0 auto;min-height:44px;padding:10px 14px;border:1px solid var(--border);border-radius:8px;background:var(--panel-solid);color:var(--muted);font-weight:700}.disclaimer{align-items:flex-start;margin:12px 0 18px;padding:16px 18px;border:1px solid var(--warning-border);border-left:5px solid var(--warning-strong);border-radius:8px;background:var(--warning-bg);color:var(--warning-text)}.disclaimer p{margin:0;line-height:1.5}.selectors{display:grid;grid-template-columns:minmax(170px,230px) minmax(220px,340px) minmax(170px,230px);gap:14px;margin:22px 0}label{display:grid;gap:8px;color:var(--label);font-size:.88rem;font-weight:800}select,input{width:100%;min-height:52px;border:1px solid var(--border-strong);border-radius:8px;background:var(--panel-solid);color:var(--text);padding:0 14px;font-size:1.05rem;outline:none}select{appearance:none;padding-right:38px;background-image:linear-gradient(45deg,transparent 50%,var(--muted) 50%),linear-gradient(135deg,var(--muted) 50%,transparent 50%);background-position:calc(100% - 18px) 50%,calc(100% - 12px) 50%;background-repeat:no-repeat;background-size:6px 6px,6px 6px}select:focus,input:focus{border-color:var(--accent);box-shadow:0 0 0 4px #197b7621}select.field-error,input.field-error{border-color:var(--error-border);box-shadow:0 0 0 4px color-mix(in srgb,var(--error-border) 28%,transparent)}.layout{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:18px;align-items:start}.question-card,.score-panel,.reference-panel{border:1px solid var(--border);border-radius:8px;background:var(--panel);box-shadow:0 16px 45px var(--shadow)}.question-card{padding:clamp(20px,4vw,34px)}.question-meta{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:22px}.question-meta span{padding:7px 10px;border-radius:8px;background:var(--accent-soft);color:var(--accent-text);font-size:.88rem;font-weight:800}.question-card h2{margin-bottom:28px;color:var(--heading);font-size:clamp(1.45rem,3vw,2.25rem);line-height:1.25}.answer-input{display:grid;grid-template-columns:minmax(180px,1.2fr) minmax(120px,.7fr) minmax(120px,.7fr);gap:12px;align-items:end}.given-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px;margin:-8px 0 22px}.given-grid div{min-height:72px;padding:12px;border:1px solid var(--border);border-radius:8px;background:var(--panel-subtle)}.given-grid span,.answer-part h3{display:block;margin:0 0 6px;color:var(--label);font-size:.82rem;font-weight:850;text-transform:uppercase}.given-grid strong{color:var(--text);font-size:1rem}.multi-answer-stack{display:grid;gap:14px}.answer-part{padding-top:2px}.choice-list{display:grid;gap:10px}.choice-option{display:flex;align-items:center;gap:12px;min-height:56px;padding:12px 14px;border:1px solid var(--border-strong);border-radius:8px;background:var(--panel-solid);color:var(--text);cursor:pointer}.choice-option.selected{border-color:var(--accent);background:var(--accent-soft);box-shadow:0 0 0 4px #197b761f}.choice-option input{width:18px;min-height:18px}.soft-disabled{opacity:.48}.button-row{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}button{min-height:48px;border:0;border-radius:8px;padding:0 16px;display:inline-flex;align-items:center;justify-content:center;gap:9px;cursor:pointer;font-weight:850}button:disabled{cursor:not-allowed;opacity:.55}.primary-button{background:var(--accent-strong);color:#fff}.secondary-button{background:var(--button-secondary);color:#fff}.theme-toggle,.ghost-button{border:1px solid var(--border-strong);background:var(--panel-solid);color:var(--text)}.feedback{margin-top:24px;padding:18px;border-radius:8px;line-height:1.5}.feedback.correct{border:1px solid var(--success-border);background:var(--success-bg);color:var(--success-text)}.feedback.incorrect{border:1px solid var(--error-border);background:var(--error-bg);color:var(--error-text)}.feedback.formula-only{border:1px solid var(--info-border);background:var(--info-bg)}.feedback p{margin-bottom:12px}.feedback p:last-child{margin-bottom:0}.unit-warning,.safety-note{font-weight:750}.formula-line{align-items:flex-start;margin:10px 0;font-weight:800}.source-metadata{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:8px;margin-top:14px}.source-metadata span{display:grid;gap:3px;padding:9px 10px;border:1px solid var(--border);border-radius:8px;background:var(--panel-solid);color:var(--text);font-size:.9rem}.source-metadata strong{color:var(--label);font-size:.72rem;text-transform:uppercase}.side-column{display:grid;gap:14px}.score-panel{padding:18px}.score-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:14px}.score-grid div{min-height:82px;padding:14px;border-radius:8px;background:var(--panel-muted)}.score-grid span,.missed-list span{color:var(--label);font-size:.82rem;font-weight:850;text-transform:uppercase}.score-grid strong{display:block;margin-top:8px;font-size:1.75rem}.score-panel .ghost-button{width:100%}.missed-list{margin-top:18px}.missed-list h2{margin-bottom:10px;font-size:1rem}.missed-list article{padding:12px 0;border-top:1px solid var(--border)}.missed-list p{margin:6px 0;color:var(--muted);font-size:.92rem}.reference-panel{padding:16px 18px}.reference-panel summary{min-height:36px;cursor:pointer;color:var(--heading);font-weight:900}.reference-grid{display:grid;gap:8px;padding-top:12px}.reference-grid span{padding:9px 10px;border-radius:8px;background:var(--panel-muted);color:var(--text);font-weight:700}@media(max-width:900px){main{width:min(100% - 22px,720px);padding-top:18px}.app-header{display:grid}.header-badge{width:fit-content}.header-actions{justify-content:flex-start}.selectors,.layout,.answer-input{grid-template-columns:1fr}.question-card{padding:20px}.button-row button{flex:1 1 190px}}@media(max-width:520px){main{width:calc(100% - 16px)}h1{font-size:2.35rem}.disclaimer{padding:14px}.question-card h2{font-size:1.35rem}.button-row{display:grid}button,select,input{min-height:54px}}