/* Інтерактивна геометрія: локальні стилі панелі § 6. */
.vec-lesson{--vec-purple:#6450c8;--vec-teal:#087f8c;margin-top:22px}
.vec-symbol{display:inline-block;position:relative;padding-top:.2em;line-height:1.35;white-space:nowrap;font-style:italic}
.vec-symbol::before{content:'⟶';position:absolute;top:-.65em;left:0;width:100%;text-align:center;font-style:normal;font-size:.9em}
.vec-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:18px}
.vec-tabs button{display:flex;align-items:center;gap:8px;border:1px solid var(--line);background:#fff;color:var(--ink);padding:10px 15px;border-radius:12px;font:inherit;font-weight:600}
.vec-tabs button span{display:grid;place-items:center;width:24px;height:24px;border-radius:50%;background:var(--primary-l);font-size:12px;color:var(--vec-purple)}
.vec-tabs button[aria-pressed=true]{background:var(--vec-purple);color:#fff;border-color:var(--vec-purple)}
.vec-tabs button[aria-pressed=true] span{background:#ffffff26;color:#fff}
.vec-layout{display:grid;grid-template-columns:minmax(0,1.55fr) minmax(290px,1fr);gap:20px;align-items:start}
.vec-workspace,.vec-explanation,.vec-experiments{background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden}
.vec-board-head{display:flex;align-items:center;gap:22px;padding:16px 20px;font-weight:700}
.vec-dot{display:inline-block;width:9px;height:9px;border-radius:50%;background:var(--vec-purple);margin-right:8px}
.vec-dot.teal{background:var(--vec-teal)}
.vec-scale{font-size:12px;color:var(--muted);font-weight:500;margin-left:auto}
.vec-board{display:block;width:100%;height:auto;overflow:hidden;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.vec-point{cursor:grab;outline:none;touch-action:none;fill:var(--vec-purple)}
.vec-point.teal{fill:var(--vec-teal)}
.vec-point:active{cursor:grabbing}
.vec-hit{fill:transparent;stroke:transparent;stroke-width:2}
.vec-handle{stroke:white;stroke-width:2}
.vec-point.selected .vec-hit{stroke:currentColor;color:var(--vec-purple);stroke-dasharray:3 4}
.vec-point.teal.selected .vec-hit{color:var(--vec-teal)}
.vec-point:focus-visible .vec-hit{stroke:var(--ink);stroke-width:3;stroke-dasharray:none}
.vec-point text{font-family:inherit;font-size:19px;font-weight:700;paint-order:stroke;stroke:#fafaff;stroke-width:5px;stroke-linejoin:round;pointer-events:none}
.vec-measures{display:flex;flex-wrap:wrap;gap:12px 26px;padding:16px 20px;color:var(--vec-purple);font-size:18px}
.vec-measures>span+span{color:var(--vec-teal)}
.vec-controls{display:flex;flex-wrap:wrap;align-items:center;gap:14px;padding:0 20px}
.vec-controls label{display:flex;align-items:center;gap:8px;font-size:13px}
.vec-controls select{width:64px;padding:7px}
.vec-check input{width:17px;height:17px;accent-color:var(--vec-purple)}
.vec-nudge{display:flex;gap:4px}
.vec-nudge button{width:40px;height:40px;border-radius:8px;background:var(--primary-l);color:var(--vec-purple);font-size:22px}
.vec-help{font-size:12px;color:var(--muted);padding:12px 20px 16px;margin:0}
.vec-explanation{padding:20px}
.vec-explain-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}
.vec-step{color:var(--muted);font-size:13px}
.vec-rule{font-size:17px;line-height:1.65;margin:0 0 12px}
.vec-note{font-size:14px;color:var(--muted);line-height:1.65;margin:0 0 16px}
.vec-task-box{background:#f1effb;border-radius:12px;padding:14px;font-size:14px;line-height:1.6;margin-bottom:16px}
.vec-task-box>b{font-size:12px;color:var(--vec-purple)}
.vec-task{margin:4px 0 0}
.vec-results{display:grid;gap:0}
.vec-results>div{display:flex;justify-content:space-between;align-items:center;gap:15px;padding:9px 0;border-bottom:1px solid var(--line);font-size:13px}
.vec-results strong{text-align:right;font-weight:600;max-width:70%}
.vec-results>div>span{color:var(--muted)}
.vec-verdict strong{color:var(--vec-purple);font-size:18px}
.vec-zero-note{color:var(--vec-teal);font-size:13px;line-height:1.6;margin:12px 0 0}
.vec-zero-note:empty{display:none}
.vec-pager{display:flex;justify-content:space-between;gap:12px;margin-top:18px}
.vec-lesson button:disabled{opacity:.4;cursor:default}
.vec-lesson button{transition:none}
.vec-lesson button:focus-visible,.vec-lesson select:focus-visible{outline:3px solid #a89ce6;outline-offset:3px}
.vec-experiments{margin-top:18px;padding:16px 20px;display:flex;align-items:end;gap:18px;flex-wrap:wrap}
.vec-experiments>label{flex:1;min-width:220px;font-size:12px;color:var(--muted)}
.vec-experiments select{display:block;margin-top:6px;font-size:14px}
.vec-actions{display:flex;gap:8px;flex-wrap:wrap}
@media(max-width:900px){.vec-layout{grid-template-columns:minmax(0,1fr)}.vec-explanation{padding:18px}.vec-tabs{gap:6px}.vec-tabs button{padding:8px 10px;font-size:13px}}
@media(max-width:480px){.vec-tabs button{flex:1 1 30%;justify-content:center}.vec-board-head{padding:14px;gap:14px}.vec-scale{font-size:10px}.vec-controls{padding:0 14px;gap:10px}.vec-measures{padding:14px;font-size:16px}.vec-help{padding:12px 14px}.vec-experiments{padding:14px}.vec-experiments>label{min-width:0;width:100%;flex:auto}.vec-actions .btn{flex:1;justify-content:center}.vec-point text{font-size:25px}}

/* Задачі з власним рисунком і перевіркою відповіді. */
.vec-practice{margin-top:30px;background:#fff;border:1px solid var(--line);border-radius:16px;padding:22px;scroll-margin-top:88px}
.vec-practice-head{display:flex;justify-content:space-between;align-items:start;gap:18px;margin-bottom:16px}
.vec-practice h2{font-size:22px;margin:0 0 6px}
.vec-practice-head p{font-size:14px;color:var(--muted);max-width:620px;margin:0;line-height:1.6}
.vec-practice-head>.pill{white-space:nowrap}
.vec-problem-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:18px}
.vec-problem-tabs button{min-width:42px;min-height:42px;padding:8px 12px;border-radius:10px;background:var(--primary-l);color:var(--vec-purple);font-weight:700}
.vec-problem-tabs button[aria-pressed=true]{background:var(--vec-purple);color:#fff}
.vec-practice-layout{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,1fr);gap:24px;align-items:start}
.vec-problem-diagram{min-width:0;border:1px solid var(--line);border-radius:12px;overflow:hidden}
.vec-problem-diagram svg{display:block;width:100%;height:auto}
.vec-problem-diagram text{font:700 23px sans-serif;text-anchor:middle;paint-order:stroke;stroke:#fafaff;stroke-width:4px}
.vec-problem-diagram p{padding:12px 14px;margin:0;font-size:13px;color:var(--muted)}
.vec-problem-count{font-size:12px;color:var(--muted)}
.vec-problem-form h3{font-size:19px;margin:7px 0 12px}
.vec-question{font-size:16px;line-height:1.7;margin:0 0 18px}
.vec-problem-form fieldset{border:0;padding:0;margin:0 0 16px;min-width:0}
.vec-option{display:flex;gap:10px;align-items:start;border:1px solid var(--line);padding:12px;border-radius:10px;font-size:14px;line-height:1.55;margin:8px 0;cursor:pointer}
.vec-option:has(input:checked){border-color:var(--vec-purple);background:#f6f4ff}
.vec-option input{width:18px;height:18px;flex:0 0 18px;margin-top:2px;accent-color:var(--vec-purple)}
.vec-answer-label{display:block;font-size:13px;color:var(--muted);margin-bottom:16px}
.vec-answer-label input{display:block;margin-top:6px;max-width:240px}
.vec-answer-actions{display:flex;gap:8px;flex-wrap:wrap}
.vec-answer-feedback{font-size:14px;line-height:1.6;margin-top:12px}
.vec-answer-feedback:empty{display:none}
.vec-answer-feedback.correct{color:#137449}
.vec-answer-feedback.retry{color:#985510}
.vec-problem-hint,.vec-solution{background:#f1effb;border-radius:10px;padding:14px;font-size:14px;line-height:1.7;margin-top:14px}
.vec-solution{background:#edf8f5}
.vec-solution p{margin:6px 0 0}
.vec-practice-footer{display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;margin-top:20px}
.vec-sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.vec-practice-jump{margin-bottom:16px;display:inline-flex;color:var(--vec-purple);font-size:14px;font-weight:600;text-underline-offset:3px}
@media(max-width:900px){.vec-practice-layout{grid-template-columns:minmax(0,1fr)}.vec-problem-diagram{max-width:600px}}
@media(max-width:480px){.vec-practice{padding:16px}.vec-practice-head{flex-direction:column;gap:10px}.vec-practice-footer .btn{flex:1;justify-content:center}.vec-practice-footer [data-practice-action=reset]{order:3;flex-basis:100%}.vec-answer-actions .btn{flex:1;justify-content:center}}