@import"https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@500;600&family=IBM+Plex+Sans:wght@400;500;600;700&family=IBM+Plex+Serif:wght@400;600&display=swap";:root{--bg: #f4f6fb;--panel: #ffffff;--ink: #1b2333;--ink-soft: #4e5a72;--ink-faint: #5d6880;--line: #dfe4ee;--line-strong: #c3cbdb;--accent: #3d5afe;--accent-soft: #eef1ff;--accent-ink: #ffffff;--value: #6d3ce8;--value-soft: #f2ecff;--metric: #0a7361;--imperial: #a8482c;--bridge: #8a3ab0;--good: #16794f;--good-soft: #e6f6ee;--warn: #985f00;--warn-soft: #fdf3e0;--bad: #c02b3a;--bad-soft: #fdecee;color-scheme:light;--radius: 12px;--shadow: 0 1px 2px rgba(20, 30, 60, .06), 0 6px 20px rgba(20, 30, 60, .06);--font: "IBM Plex Sans", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;--serif: "IBM Plex Serif", ui-serif, Georgia, "Times New Roman", serif;--mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace}@media(prefers-color-scheme:dark){:root:not([data-theme=light]){--bg: #12151d;--panel: #1b202b;--ink: #e8ecf5;--ink-soft: #a3adc2;--ink-faint: #8a94a9;--line: #2b3242;--line-strong: #3b4457;--accent: #8ea2ff;--accent-soft: #232a44;--accent-ink: #12151d;--value: #b69cff;--value-soft: #2a2440;--metric: #4fd1b5;--imperial: #eb9270;--bridge: #c68ae6;--good: #5fd3a0;--good-soft: #16302a;--warn: #e5b25a;--warn-soft: #33291a;--bad: #ff8a95;--bad-soft: #3a1f24;--shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 6px 20px rgba(0, 0, 0, .35);color-scheme:dark}}:root[data-theme=dark]{--bg: #12151d;--panel: #1b202b;--ink: #e8ecf5;--ink-soft: #a3adc2;--ink-faint: #8a94a9;--line: #2b3242;--line-strong: #3b4457;--accent: #8ea2ff;--accent-soft: #232a44;--accent-ink: #12151d;--value: #b69cff;--value-soft: #2a2440;--metric: #4fd1b5;--imperial: #eb9270;--bridge: #c68ae6;--good: #5fd3a0;--good-soft: #16302a;--warn: #e5b25a;--warn-soft: #33291a;--bad: #ff8a95;--bad-soft: #3a1f24;--shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 6px 20px rgba(0, 0, 0, .35);color-scheme:dark}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font);-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent}.app{max-width:1120px;margin:0 auto;padding:24px 20px 64px;display:flex;flex-direction:column;gap:18px}.app-head{display:flex;flex-wrap:wrap;gap:12px;align-items:flex-start;justify-content:space-between}.app-head h1{font-family:var(--serif);font-size:1.4rem;font-weight:600;margin:0;letter-spacing:-.01em}.tagline{margin:4px 0 0;color:var(--ink-soft);font-size:.9rem}.head-actions{display:flex;gap:8px;flex-wrap:wrap}.btn{font:inherit;font-size:.86rem;font-weight:500;padding:8px 14px;border-radius:999px;border:1px solid var(--line-strong);background-color:var(--panel);color:var(--ink);cursor:pointer;transition:transform 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.sub,.approx{color:var(--ink-faint);font-size:.76rem;font-style:normal}.approx{margin-left:5px}.problem-list{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:6px}.problem-btn{font:inherit;font-size:.84rem;text-align:left;width:100%;display:flex;justify-content:space-between;align-items:center;gap:12px;padding:10px 12px;border:1px solid var(--line);border-radius:9px;background:var(--bg);color:var(--ink);cursor:pointer}.problem-btn:hover{border-color:var(--accent)}.problem-btn.active{border-color:var(--accent);background:var(--accent-soft)}.steps-badge{font-family:var(--mono);font-size:.7rem;color:var(--ink-faint);white-space:nowrap}.hint-text{font-size:.8rem;color:var(--ink-soft);margin:0 0 8px}@media(max-width:640px){.app{padding:16px 12px 48px}.app-head h1{font-size:1.15rem}.slot{min-width:128px}.slot-big{min-width:140px}.term-fraction{min-width:144px}}.slot:focus-visible,.card:focus-visible,.add-col:focus-visible,.btn:focus-visible{outline:2px solid 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