:root {
  font-family: ui-rounded, "Arial Rounded MT Bold", "Noto Sans KR", "Malgun Gothic", system-ui, sans-serif;
  color: #243047;
  background: #f5f8fb;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --ink: #243047;
  --muted: #536176;
  --paper: #f5f8fb;
  --surface: #fff;
  --line: #cbd5e1;
  --blue: #3157a4;
  --blue-dark: #203f7e;
  --teal: #197d7b;
  --coral: #c94d3c;
  --yellow: #ffe08a;
  --purple: #6547b4;
  --focus: #155eef;
  color-scheme: light;
}

* { box-sizing: border-box; }
html { min-width: 320px; min-height: 100%; scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; min-height: 100vh; background: var(--paper); }
button, input { font: inherit; }
button { color: inherit; }
button:focus-visible, a:focus-visible, input:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }
.skip-link { position: fixed; z-index: 20; top: 8px; left: 8px; transform: translateY(-160%); padding: 12px 16px; border-radius: 12px; color: #fff; background: var(--blue-dark); }
.skip-link:focus { transform: translateY(0); }
.loading-shell, .noscript { max-width: 60rem; margin: 10vh auto; padding: 2rem; font-size: 1.2rem; }
#app { min-height: 100vh; }
.site-shell { width: min(100% - 2rem, 70rem); margin: 0 auto; padding: max(12px, env(safe-area-inset-top)) 0 max(24px, env(safe-area-inset-bottom)); }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 12px; border: 0; padding: 6px 0; background: none; font-weight: 900; font-size: 1.12rem; letter-spacing: -.025em; cursor: pointer; }
.brand-mark { display: grid; width: 42px; height: 42px; place-items: center; border-radius: 15px; color: #fff; background: var(--blue); box-shadow: 0 4px 0 #213f7b; font-size: 1.45rem; }
.top-actions { display: flex; align-items: center; gap: 8px; }
.icon-button { display: inline-flex; min-width: 52px; min-height: 52px; align-items: center; justify-content: center; gap: 8px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 16px; background: #fff; font-size: .98rem; font-weight: 750; cursor: pointer; }
.icon-button:hover { background: #edf3fb; }
.review-strip { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin: 8px 0 18px; padding: 10px 14px; border: 1px solid #becdec; border-radius: 16px; background: #eaf0ff; color: #203f7e; font-size: .92rem; font-weight: 800; }
.review-tag { flex: 0 0 auto; padding: 5px 9px; border-radius: 999px; background: #fff; font-size: .78rem; }
.activity-layout { display: grid; grid-template-columns: minmax(0, 1fr) 16.25rem; gap: 18px; align-items: start; }
.workbench { min-width: 0; overflow: hidden; border: 1px solid #d4deea; border-radius: 30px; background: var(--surface); box-shadow: 0 12px 35px #253c5910; }
.workbench-head { display: flex; align-items: center; justify-content: space-between; gap: 14px; padding: 22px 24px 0; }
.eyebrow { margin: 0; color: var(--muted); font-size: .92rem; font-weight: 800; }
.round-count { flex: 0 0 auto; padding: 8px 12px; border-radius: 999px; background: #eef3f9; color: #35445c; font-weight: 800; font-variant-numeric: tabular-nums; }
.prompt { min-height: 84px; margin: 12px 24px 0; font-size: clamp(1.6rem, 3.4vw, 2.25rem); line-height: 1.3; letter-spacing: -.04em; }
.prompt-support { min-height: 26px; margin: 6px 24px 0; color: var(--muted); font-size: 1rem; line-height: 1.45; }
.board { display: grid; min-height: 252px; place-items: center; margin: 14px 20px 4px; padding: 18px; border-radius: 24px; background: #f0f6f7; }
.objects { display: grid; width: min(100%, 540px); grid-template-columns: repeat(5, minmax(44px, 72px)); justify-content: center; gap: clamp(9px, 2vw, 17px); padding: 8px; }
.count-object { position: relative; display: grid; width: clamp(56px, 9vw, 68px); aspect-ratio: 1; place-items: center; border: 3px solid #0f6262; border-radius: 20px 20px 24px 24px; color: #083c40; background: #54c2b2; box-shadow: 0 5px 0 #167a73; font-size: 1.3rem; font-weight: 900; cursor: pointer; touch-action: manipulation; }
.count-object.is-counted::after { position: absolute; inset: -5px; display: grid; place-items: start end; content: attr(data-count); border: 4px solid #193e82; border-radius: inherit; color: #fff; background: #193e82; font-size: .84rem; line-height: 1; padding: 4px; box-shadow: 0 0 0 2px #fff; }
.equation { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: clamp(8px, 2vw, 22px); font-size: clamp(2.25rem, 7vw, 4rem); font-weight: 950; font-variant-numeric: tabular-nums; letter-spacing: -.06em; }
.equation .term { display: inline-grid; min-width: 1.6em; min-height: 1.6em; place-items: center; border-radius: 19px; color: #124e51; background: #d5f2ec; }
.equation .operator { color: var(--purple); }
.ten-frame { display: grid; grid-template-columns: repeat(5, 52px); gap: 9px; margin: 18px 0; }
.ten-cell { display: grid; width: 52px; height: 52px; place-items: center; border: 3px solid #8795a7; border-radius: 14px; background: white; }
.ten-cell.filled { border-color: #106c6a; background: #4cbcae; box-shadow: inset 0 -4px #167a73; }
.ten-cell.second-group { border-color: #6547b4; background: #c6b7f2; box-shadow: inset 0 -4px #8b74c5; color: #392864; }
.ten-cell.removed { border-color: #8d5b31; background: repeating-linear-gradient(135deg, #fff 0 7px, #f0dfd0 7px 11px); color: #633a21; font-size: 1.4rem; }
.numberline { width: min(100%, 620px); padding: 16px 8px; }
.line-track { display: grid; grid-template-columns: repeat(11, minmax(0, 1fr)); align-items: center; justify-content: space-between; position: relative; gap: 0; padding: 28px 0 0; }
.line-track::before { position: absolute; top: 36px; right: 0; left: 0; height: 5px; border-radius: 999px; content: ""; background: #51647d; }
.line-node { position: relative; z-index: 1; display: grid; width: auto; min-width: 0; min-height: 72px; place-items: center; gap: 10px; background: transparent; font-size: .94rem; font-weight: 850; }
.line-node::before { display: block; width: 16px; height: 16px; border: 3px solid #3e5370; border-radius: 50%; content: ""; background: #fff; }
.line-node.current::before { border-color: #fff; outline: 4px solid #2467b5; background: #2467b5; box-shadow: 0 0 0 7px #d9e9fc; }
.counted-readout { min-height: 30px; color: #34445b; font-size: 1rem; font-weight: 800; text-align: center; }
.empty-count-group { display: grid; min-width: 11rem; min-height: 9rem; place-content: center; justify-items: center; gap: 7px; padding: 18px 24px; border: 3px dashed #73859a; border-radius: 22px; color: #34445b; background: #fff; font-weight: 850; text-align: center; }
.answer-row { display: grid; grid-template-columns: repeat(4, minmax(54px, 1fr)); gap: 10px; padding: 14px 24px 0; }
.answer-button, .move-button { min-height: 62px; border: 2px solid #b4c3d5; border-radius: 19px; color: #20324b; background: #fff; font-size: 1.55rem; font-weight: 900; cursor: pointer; touch-action: manipulation; }
.answer-button:hover, .move-button:hover { border-color: #3157a4; background: #edf3ff; }
.answer-button[aria-pressed="true"] { border-color: #3157a4; color: #203f7e; background: #e5eeff; box-shadow: inset 0 0 0 2px #3157a4; }
.answer-button.correct { border-color: #176b45; color: #125439; background: #e5f5ed; }
.answer-button.incorrect { border-color: #a56600; color: #674200; background: #fff3d5; }
.move-controls { display: flex; justify-content: center; gap: 12px; padding: 14px 20px 0; }
.move-button { flex: 1 1 0; max-width: 190px; font-size: 1.06rem; }
.workbench-footer { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 10px; padding: 16px 24px 22px; }
.feedback { display: flex; flex: 1 1 180px; flex-direction: column; gap: 4px; min-height: 28px; margin: 0; color: #315164; font-size: 1rem; font-weight: 800; }
.feedback-label { font-size: .83rem; font-weight: 900; }
.feedback-copy { display: block; line-height: 1.5; }
.feedback[data-tone="gentle"], .feedback[data-tone="hint"] { flex-basis: 100%; padding: 12px 14px; border: 1px solid #e2bf70; border-radius: 15px; }
.feedback[data-tone="gentle"] { color: #604600; background: #fff6df; }
.feedback[data-tone="hint"] { border-color: #b5d2df; color: #194b64; background: #edf8fb; }
.feedback[data-tone="good"] { color: #145b3d; }
.footer-actions { display: flex; flex-wrap: wrap; gap: 9px; }
.secondary-button, .primary-button { display: inline-flex; min-height: 56px; align-items: center; justify-content: center; gap: 8px; padding: 10px 17px; border: 2px solid #b8c7d8; border-radius: 17px; background: #fff; font-size: 1rem; font-weight: 850; cursor: pointer; touch-action: manipulation; }
.secondary-button:hover { background: #edf3fb; }
.primary-button { border-color: #203f7e; color: white; background: #3157a4; box-shadow: 0 4px 0 #203f7e; }
.primary-button:hover { background: #25498d; }
.primary-button:active { transform: translateY(2px); box-shadow: 0 2px 0 #203f7e; }
.primary-button:disabled, .secondary-button:disabled, .answer-button:disabled { cursor: not-allowed; opacity: .55; }
.activity-rail { display: grid; gap: 10px; }
.rail-heading { margin: 0 0 2px; color: var(--muted); font-size: .95rem; font-weight: 850; }
.activity-card { display: grid; min-height: 72px; grid-template-columns: 44px 1fr; align-items: center; gap: 10px; padding: 10px 12px; border: 2px solid #d0dae5; border-radius: 19px; background: #fff; text-align: left; cursor: pointer; }
.activity-card:hover { border-color: #7796ca; }
.activity-card[aria-current="true"] { border-color: #3157a4; background: #eaf0ff; box-shadow: inset 0 0 0 1px #3157a4; }
.activity-icon { display: grid; width: 44px; height: 44px; place-items: center; border-radius: 15px; background: #e5f4f0; font-size: 1.35rem; }
.activity-card:nth-of-type(2) .activity-icon { background: #f0eaff; }
.activity-card:nth-of-type(3) .activity-icon { background: #fff1d5; }
.activity-card:nth-of-type(4) .activity-icon { background: #ffe8e2; }
.activity-title { display: block; font-size: 1.02rem; font-weight: 900; }
.activity-meta { display: block; margin-top: 3px; color: var(--muted); font-size: .86rem; }
.progress-card { padding: 16px; border-radius: 20px; background: #e8f3f1; }
.progress-title { margin: 0 0 7px; font-size: 1rem; font-weight: 900; }
.progress-copy { margin: 0; color: #304d4b; font-size: .93rem; line-height: 1.45; }
.privacy-note { margin: 12px 2px; color: var(--muted); font-size: .84rem; line-height: 1.55; }
.completion { max-width: 620px; margin: 24px auto; padding: clamp(24px, 6vw, 52px); border: 1px solid #d5deea; border-radius: 30px; background: #fff; text-align: center; box-shadow: 0 12px 35px #253c5910; }
.completion-mark { display: grid; width: 74px; height: 74px; place-items: center; margin: 0 auto 16px; border-radius: 24px; background: #e1f4ed; font-size: 2.3rem; }
.completion h1 { margin: 0; font-size: clamp(1.8rem, 5vw, 2.5rem); letter-spacing: -.04em; }
.completion p { color: #43536b; font-size: 1.1rem; line-height: 1.6; }
.completion-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-top: 20px; }
.completion-actions > button { flex: 1 1 9rem; }
.parent-shell { max-width: 720px; margin: 18px auto; padding: clamp(20px, 5vw, 42px); border: 1px solid #d5deea; border-radius: 28px; background: #fff; }
.parent-shell h1 { margin: 0 0 8px; font-size: clamp(1.7rem, 5vw, 2.2rem); }
.parent-shell > p { color: #4e5b70; font-size: 1.02rem; line-height: 1.6; }
.parent-stat-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin: 20px 0; }
.parent-stat { min-height: 115px; padding: 16px; border-radius: 18px; background: #f1f5fa; }
.parent-stat strong { display: block; font-size: 1.65rem; font-variant-numeric: tabular-nums; }
.parent-stat span { display: block; margin-top: 4px; color: #4e5b70; font-size: .95rem; line-height: 1.4; }
.boundary-note { padding: 14px; border-left: 4px solid #bd7a14; border-radius: 10px; background: #fff6df; color: #5c4319 !important; }
.gate-form { display: grid; gap: 14px; max-width: 440px; margin-top: 22px; }
.gate-equation { display: grid; gap: 6px; padding: 18px; border-radius: 16px; background: #eaf0ff; font-size: 1.15rem; font-weight: 800; }
.gate-answer { width: 100%; min-height: 56px; padding: 10px 14px; border: 2px solid #9aaabe; border-radius: 14px; font-size: 1.2rem; }
.delete-panel { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 12px; margin-top: 24px; padding: 18px; border: 1px solid #e1b9ad; border-radius: 18px; background: #fff8f6; }
.delete-panel p { flex: 1 1 230px; margin: 0; color: #5b3932; line-height: 1.5; }
.delete-button { border-color: #a12828; color: #8d2222; }
.modal-backdrop { position: fixed; z-index: 10; inset: 0; display: grid; place-items: center; padding: 16px; background: #18233799; }
.modal { width: min(100%, 440px); padding: 24px; border-radius: 24px; background: #fff; box-shadow: 0 20px 80px #0003; }
.modal h2 { margin: 0 0 9px; }
.modal p { color: #46556a; line-height: 1.5; }
.modal input { width: 100%; min-height: 56px; margin: 8px 0 14px; padding: 10px 14px; border: 2px solid #9aaabe; border-radius: 14px; font-size: 1.15rem; }
.modal-actions { display: flex; justify-content: flex-end; gap: 8px; }
.toast { position: fixed; z-index: 8; right: 16px; bottom: max(16px, env(safe-area-inset-bottom)); left: 16px; width: fit-content; max-width: 540px; margin: 0 auto; padding: 13px 18px; border-radius: 16px; color: white; background: #243047; box-shadow: 0 8px 24px #0003; font-weight: 800; }
.visually-hidden { position: absolute !important; width: 1px !important; height: 1px !important; overflow: hidden !important; clip: rect(1px,1px,1px,1px) !important; white-space: nowrap !important; clip-path: inset(50%) !important; }
.sr-status { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(1px,1px,1px,1px); }
.site-footer { margin: 18px 0 0; color: #536176; font-size: .86rem; line-height: 1.55; text-align: center; }

@media (max-width: 760px) {
  .site-shell { width: min(100% - 1.25rem, 44rem); }
  .activity-layout { grid-template-columns: 1fr; }
  .activity-rail { grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 7px; }
  .rail-heading { grid-column: 1 / -1; }
  .activity-card { display: flex; min-height: 74px; flex-direction: column; justify-content: center; gap: 4px; padding: 6px 4px; text-align: center; }
  .activity-icon { width: 36px; height: 36px; border-radius: 13px; font-size: 1.15rem; }
  .activity-title { font-size: .9rem; }
  .activity-meta { display: none; }
  .progress-card { grid-column: 1 / -1; }
  .privacy-note { grid-column: 1 / -1; margin: 0; }
  .board { min-height: 220px; margin: 13px 12px 4px; padding: 12px 7px; }
  .prompt { margin-right: 18px; margin-left: 18px; font-size: clamp(1.55rem, 7vw, 2rem); }
  .prompt-support { margin-right: 18px; margin-left: 18px; }
  .workbench-head { padding: 18px 18px 0; }
  .answer-row { gap: 8px; padding: 12px 14px 0; }
  .answer-button { min-height: 58px; }
  .workbench-footer { padding: 13px 16px 18px; }
  .line-node { font-size: .82rem; }
}

@media (max-width: 390px) {
  .site-shell { width: calc(100% - 1rem); }
  .brand { font-size: 1rem; }
  .brand-mark { width: 38px; height: 38px; }
  .icon-button { min-width: 48px; min-height: 48px; padding: 7px; font-size: .9rem; }
  .review-strip { font-size: .82rem; }
  .objects { grid-template-columns: repeat(4, minmax(44px, 58px)); gap: 10px; }
  .count-object { width: 48px; }
  .ten-frame { grid-template-columns: repeat(5, 43px); gap: 7px; }
  .ten-cell { width: 43px; height: 43px; }
  .line-track { margin: 0 -8px; }
  .line-node { font-size: .75rem; gap: 8px; }
  .line-node::before { width: 13px; height: 13px; }
  .feedback { flex-basis: 100%; }
  .footer-actions { width: 100%; }
  .footer-actions > button { flex: 1; }
  .parent-stat-grid { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}

/* Math atelier: crisp cobalt navigation, ink surfaces and vivid manipulatives. */
:root {
  --ink: #172944;
  --muted: #465d78;
  --paper: #edf3ff;
  --surface: #ffffff;
  --line: #b7c7de;
  --blue: #2859c5;
  --blue-dark: #173d91;
  --teal: #087f78;
  --coral: #b83e31;
  --yellow: #f2ca53;
  --purple: #5741a5;
  --focus: #6138ce;
  color: var(--ink);
  background: var(--paper);
}
body { color: var(--ink); background: var(--paper); }
button { color: var(--ink); }
.site-shell { width: min(100% - 2.5rem, 76rem); padding-top: max(12px, env(safe-area-inset-top)); }
.topbar { min-height: 72px; }
.brand { min-height: 56px; color: var(--ink); font-size: 1.18rem; }
.brand-mark { width: 44px; height: 44px; border-radius: 15px; color: #fff; background: #234ea9; box-shadow: 0 4px 0 #17356f; }
.top-actions { gap: 10px; }
.icon-button { min-height: 48px; border-color: #b3c3da; border-radius: 14px; color: #203d67; background: #fff; }
.icon-button:hover, .secondary-button:hover { border-color: #2859c5; color: #163f94; background: #eef3ff; }
.review-strip { margin: 5px 0 18px; padding: 10px 14px; border-color: #9db8ef; border-radius: 12px; color: #153d81; background: #dfeaff; font-size: .9rem; }
.review-tag { padding: 5px 9px; color: #38485e; background: #fff; font-size: .8rem; }
.home-main { display: grid; gap: 27px; }
.home-hero { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(300px, .85fr); gap: 22px; align-items: stretch; padding: clamp(20px, 3vw, 34px); border: 1px solid #214681; border-radius: 27px; color: #fff; background: linear-gradient(132deg, #142e57 0%, #204f9e 72%, #2b62bd 100%); box-shadow: 0 18px 40px #183b751f; }
.home-hero-copy { display: grid; align-content: start; gap: 12px; min-width: 0; }
.home-hero .eyebrow { color: #ccdcf9; }
.home-hero-copy h1 { margin: 0; font-size: clamp(2rem, 4.1vw, 3.05rem); line-height: 1.14; letter-spacing: -.045em; }
.home-hero-copy > p:not(.eyebrow) { max-width: 38rem; margin: 0; color: #e5edfb; font-size: 1.06rem; line-height: 1.55; }
.home-level { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; margin-top: 6px; }
.level-choice { display: grid; min-height: 68px; align-content: center; gap: 3px; padding: 9px 10px; border: 1px solid #b2c5e1; border-radius: 13px; color: #1c3558; background: #fff; text-align: left; cursor: pointer; touch-action: manipulation; }
.home-hero .level-choice { border-color: #d3def0; }
.level-choice strong { font-size: .9rem; line-height: 1.3; }
.level-choice span { color: #4c607c; font-size: .78rem; line-height: 1.3; }
.level-choice[aria-pressed="true"] { border: 2px solid #f2ca53; background: #fff9dd; box-shadow: 0 0 0 2px #f2ca5350; }
.today-card { display: grid; align-content: start; gap: 9px; min-width: 0; padding: clamp(18px, 2.2vw, 25px); border: 1px solid #d1dbee; border-radius: 20px; color: var(--ink); background: #fff; box-shadow: 0 12px 28px #0e28501f; }
.today-card-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.today-kicker { color: #2859c5; font-size: .91rem; font-weight: 900; }
.today-duration { color: #4b6079; font-size: .79rem; font-weight: 700; }
.today-card h2 { margin: 1px 0 0; font-size: clamp(1.8rem, 3vw, 2.4rem); letter-spacing: -.045em; }
.today-card p { margin: 0; color: #455a74; font-size: .96rem; line-height: 1.5; }
.today-card .today-set { color: #213957; font-size: 1.12rem; font-weight: 850; }
.primary-button, .secondary-button { min-height: 54px; border-radius: 14px; font-size: 1rem; }
.primary-button { border-color: #183c88; background: #2859c5; box-shadow: 0 4px 0 #193e8b; }
.primary-button:hover { background: #1c4eaf; }
.today-start { width: 100%; margin-top: 5px; }
.resume-card { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 10px; margin-top: 5px; padding-top: 13px; border-top: 1px solid #d9e2ef; }
.resume-card > div { display: grid; gap: 3px; }
.resume-card strong { font-size: .9rem; }
.resume-card span { color: #4d6079; font-size: .85rem; }
.resume-card .secondary-button { min-height: 44px; padding-inline: 12px; }
.catalog-section { display: grid; gap: 14px; }
.section-heading { display: flex; flex-wrap: wrap; align-items: end; justify-content: space-between; gap: 12px; }
.section-heading h2, .home-guides h2 { margin: 4px 0 0; font-size: clamp(1.45rem, 2.5vw, 1.9rem); letter-spacing: -.035em; }
.section-heading > p { margin: 0 2px 3px; color: #485f7b; font-size: .92rem; }
.home-activity-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 11px; }
.home-activity-card { display: grid; min-height: 130px; grid-template-columns: 52px minmax(0, 1fr) 28px; align-items: start; gap: 12px; padding: 17px 16px; border: 1px solid #c2cfe2; border-radius: 17px; color: var(--ink); background: #fff; text-align: left; cursor: pointer; transition: border-color .16s ease, box-shadow .16s ease, transform .16s ease; touch-action: manipulation; }
.home-activity-card:hover { transform: translateY(-2px); border-color: #668bd0; box-shadow: 0 9px 20px #1e478715; }
.home-card-icon { display: grid; width: 50px; height: 50px; place-items: center; border-radius: 15px; color: #17386d; background: #dfebff; font-size: 1.02rem; font-weight: 950; letter-spacing: -.05em; }
.home-activity-card:nth-child(3n + 2) .home-card-icon { color: #08584e; background: #d9f1eb; }
.home-activity-card:nth-child(3n) .home-card-icon { color: #654016; background: #fff0c9; }
.home-activity-card:nth-child(3n + 4) .home-card-icon { color: #714044; background: #fde5e5; }
.home-card-copy { display: grid; gap: 5px; min-width: 0; }
.home-card-copy strong { font-size: 1.08rem; line-height: 1.35; }
.home-card-copy > span { color: #384f6e; font-size: .89rem; line-height: 1.4; }
.home-card-copy small { margin-top: 2px; color: #51647e; font-size: .79rem; line-height: 1.35; }
.home-card-mark { display: grid; width: 26px; height: 26px; place-items: center; border-radius: 50%; color: #244d99; background: #eaf1ff; font-size: 1.2rem; font-weight: 700; }
.home-guides { display: grid; grid-template-columns: .75fr 1.25fr; gap: 20px; padding: 20px 22px; border: 1px solid #c4d1e4; border-radius: 19px; background: #fff; }
.home-guides ul { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; margin: 0; padding: 0; list-style: none; }
.home-guides li { display: grid; align-content: start; gap: 5px; padding: 12px; border-radius: 12px; background: #f2f6fc; }
.home-guides li strong { color: #203d66; font-size: .9rem; }
.home-guides li span { color: #445a77; font-size: .84rem; line-height: 1.45; }
.home-guide-tips { grid-column: 1 / -1; }
.home-guide-tips ol { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px 22px; padding-left: 22px; }
.home-guide-tips ol li { display: list-item; padding: 3px 0; color: #394e69; background: none; font-size: .86rem; }
.home-privacy { margin: 0; color: #4e627d; font-size: .88rem; line-height: 1.5; }
.home-status { margin: 0; padding: 11px 14px; border: 1px solid #9fcdb8; border-radius: 12px; color: #14543c; background: #e6f6ed; font-weight: 800; }
.catalog-main { display: grid; gap: 15px; }
.back-button { width: fit-content; min-height: 44px; padding: 8px 13px; border: 1px solid #aebfd7; border-radius: 12px; color: #284a7b; background: #fff; font-weight: 800; cursor: pointer; }
.catalog-title-block { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 22px 24px; border-radius: 20px; color: #fff; background: #1b3b70; }
.catalog-title-block .eyebrow { color: #cbdaf4; }
.catalog-title-block h1 { margin: 5px 0; font-size: clamp(1.8rem, 4vw, 2.55rem); letter-spacing: -.04em; }
.catalog-title-block p:not(.eyebrow) { max-width: 55rem; margin: 0; color: #e0e9f8; font-size: .97rem; line-height: 1.5; }
.catalog-completion { display: grid; flex: 0 0 auto; min-width: 125px; justify-items: center; padding: 14px; border-radius: 15px; color: #1b3760; background: #fff; }
.catalog-completion strong { font-size: 1.8rem; }
.catalog-completion span { font-size: .8rem; }
.catalog-groups { display: grid; gap: 10px; }
.lesson-pack { overflow: hidden; border: 1px solid #c3d0e3; border-radius: 16px; background: #fff; }
.lesson-pack summary { display: flex; min-height: 72px; align-items: center; justify-content: space-between; gap: 12px; padding: 13px 17px; cursor: pointer; list-style: none; }
.lesson-pack summary::-webkit-details-marker { display: none; }
.lesson-pack summary > span:first-child { display: grid; gap: 4px; }
.lesson-pack summary strong { font-size: 1rem; }
.lesson-pack summary small { color: #4c607b; font-size: .86rem; line-height: 1.4; }
.pack-count { display: grid; min-width: 38px; min-height: 34px; place-items: center; border-radius: 10px; color: #204789; background: #e9f0ff; font-weight: 900; }
.lesson-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 9px; padding: 0 12px 13px; }
.lesson-card { display: grid; gap: 5px; min-height: 96px; padding: 12px; border: 1px solid #d1dbe8; border-radius: 12px; color: var(--ink); background: #f9fbff; text-align: left; cursor: pointer; touch-action: manipulation; }
.lesson-card:hover { border-color: #5d80c4; background: #f0f5ff; }
.lesson-card-top { display: flex; align-items: start; justify-content: space-between; gap: 8px; }
.lesson-card-top strong { font-size: .95rem; line-height: 1.35; }
.lesson-card-top span { flex: 0 0 auto; color: #526782; font-size: .77rem; }
.lesson-focus { color: #244c8a; font-size: .84rem; font-weight: 850; }
.lesson-description, .catalog-footnote { color: #4a5f79; font-size: .83rem; line-height: 1.4; }
.catalog-footnote { margin: 0; }
.activity-layout { grid-template-columns: minmax(0, 1fr) 16rem; gap: 17px; }
.workbench { border-color: #c4d1e2; border-radius: 22px; box-shadow: 0 10px 26px #1c3d6710; }
.workbench-head { padding: 22px 24px 0; }
.round-count { color: #24436e; background: #e8effa; }
.session-progress { display: block; width: calc(100% - 48px); height: 7px; margin: 14px 24px 0; overflow: hidden; border: 0; border-radius: 99px; accent-color: #2859c5; }
.session-progress::-webkit-progress-bar { border-radius: 99px; background: #e2eaf6; }
.session-progress::-webkit-progress-value { border-radius: 99px; background: #2859c5; }
.prompt { min-height: 76px; margin-top: 16px; color: #1a2f4d; }
.prompt-support { min-height: 26px; color: #455b77; }
.board { min-height: 250px; border: 1px solid #dce5f1; border-radius: 18px; background: linear-gradient(135deg, #f3f7ff, #edf5f5); }
.count-object { border-color: #086e69; border-radius: 17px; background: #45b9a6; box-shadow: 0 4px 0 #08756d; }
.count-object.is-counted::after { border-color: #264ea4; background: #264ea4; }
.equation .term { color: #1b464a; background: #d7f0eb; }
.ten-cell { border-color: #879ab3; }
.ten-cell.filled { border-color: #087f78; background: #64c5ad; box-shadow: inset 0 -4px #08796f; }
.ten-cell.second-group { border-color: #5841a5; background: #c6baf0; }
.answer-row { padding-inline: 24px; }
.answer-button, .move-button { border-color: #b8c7dc; border-radius: 14px; color: #1e395f; }
.answer-button[aria-pressed="true"] { border-color: #2859c5; color: #173d91; background: #e7efff; box-shadow: inset 0 0 0 1px #2859c5; }
.answer-word { padding: 9px 10px; font-size: .98rem; line-height: 1.35; }
.answer-row-words { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.workbench-footer { padding-top: 15px; }
.footer-actions { justify-content: flex-end; }
.activity-rail { align-content: start; }
.lesson-aside { padding: 17px; border: 1px solid #c5d2e4; border-radius: 17px; background: #fff; }
.lesson-aside h2 { margin: 8px 0; font-size: 1.15rem; line-height: 1.35; }
.lesson-aside p:not(.eyebrow) { margin: 0; color: #475e78; font-size: .9rem; line-height: 1.5; }
.focus-chip { display: inline-flex; margin-top: 12px; padding: 6px 9px; border-radius: 9px; color: #1c488e; background: #eaf1ff; font-size: .82rem; font-weight: 850; }
.progress-card { border: 1px solid #b3ded1; background: #e5f4ef; }
.progress-number { display: block; margin: 7px 0; color: #0c5d54; font-size: 2rem; font-variant-numeric: tabular-nums; }
.parent-shell { border-color: #c4d1e2; border-radius: 22px; }
.parent-shell h1 { color: #1a3151; }
.parent-summary { display: grid; gap: 12px; margin: 20px 0; padding: 18px; border: 1px solid #c7d6ed; border-radius: 17px; background: #f3f7ff; }
.parent-summary h2 { margin: 4px 0; font-size: 1.25rem; }
.parent-summary p:not(.eyebrow) { margin: 0; color: #4c6078; font-size: .91rem; line-height: 1.5; }
.parent-stat-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; margin: 0; }
.parent-stat { min-height: 85px; border: 1px solid #d2ddea; background: #fff; }
.parent-stat strong { color: #1b4385; }
.parent-stat span { font-size: .86rem; }
.parent-section { display: grid; gap: 8px; margin: 22px 0; }
.parent-section h2 { margin: 0; font-size: 1.25rem; }
.parent-section > p:not(.eyebrow) { margin: 0; color: #4d627c; line-height: 1.5; }
.completion { border-color: #c5d2e4; border-radius: 22px; box-shadow: 0 10px 26px #1c3d6710; }
.completed-concept { display: inline-block; padding: 7px 11px; border-radius: 10px; color: #204786 !important; background: #eaf1ff; font-weight: 850; }
.site-footer { color: #4b6078; font-size: .86rem; }

.comparison-board { display: grid; width: min(100%, 690px); grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: center; gap: 12px; }
.compare-group { display: grid; min-width: 0; justify-items: center; gap: 10px; padding: 12px; border: 1px solid #c6d2e2; border-radius: 16px; background: #fff; }
.compare-label { color: #334d6c; font-size: .92rem; font-weight: 900; }
.compare-dots { display: grid; width: 100%; min-height: 96px; grid-template-columns: repeat(5, minmax(10px, 22px)); align-content: center; justify-content: center; gap: 6px; }
.compare-dots span { width: clamp(12px, 2.5vw, 19px); aspect-ratio: 1; border-radius: 50%; background: #3676ce; }
.compare-dots.right span { background: #e17656; }
.compare-count { color: #1d3b63; font-size: .95rem; font-weight: 900; }
.compare-divider { color: #586d86; font-size: .8rem; font-weight: 850; }
.compose-board { display: grid; justify-items: center; gap: 12px; }
.compose-equation { display: flex; align-items: center; gap: clamp(9px, 2vw, 18px); color: #203958; font-size: clamp(2rem, 6vw, 3.5rem); font-weight: 950; font-variant-numeric: tabular-nums; }
.unknown-term { display: grid; min-width: 1.35em; min-height: 1.35em; place-items: center; border: 2px dashed #7287a4; border-radius: 14px; color: #5c7190; background: #fff; }
.compose-frame { display: grid; grid-template-columns: repeat(5, minmax(34px, 54px)); gap: 7px; }
.compose-cell { display: grid; width: clamp(37px, 8vw, 52px); aspect-ratio: 1; place-items: center; border: 2px solid #94a4ba; border-radius: 11px; color: #075f58; background: #fff; font-size: 1.2rem; }
.compose-cell.is-filled { border-color: #0b8277; background: #6bd1b9; }
.place-value-board { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: clamp(12px, 3vw, 24px); width: min(100%, 500px); min-height: 145px; }
.place-bundles, .place-ones { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: 7px; max-width: 220px; }
.ten-bundle { display: grid; justify-items: center; gap: 4px; padding: 7px; border: 2px solid #2859c5; border-radius: 12px; color: #183d80; background: #e4edff; font-weight: 950; }
.bundle-lines { display: grid; grid-template-columns: repeat(5, 8px); gap: 2px; }
.bundle-lines i { width: 8px; height: 8px; border-radius: 2px; background: #4c7bd0; }
.place-plus { color: #6752a2; font-size: 2rem; font-weight: 900; }
.place-one { display: grid; width: 34px; aspect-ratio: 1; place-items: center; border: 2px solid #07756f; border-radius: 9px; color: #075951; background: #8ce0ce; font-size: .88rem; }
.missing-pattern { border: 2px dashed #687f9e; color: #536a88; background: #eef3fb; font-size: 1.45rem; font-weight: 900; }
.session-progress:focus-visible, .line-track:focus-visible { outline: 3px solid var(--focus); outline-offset: 4px; }

@media (max-width: 860px) {
  .home-hero { grid-template-columns: 1fr; }
  .home-hero-copy { gap: 9px; }
  .today-card { grid-template-columns: 1fr 1fr; align-items: center; }
  .today-card-head, .today-card h2, .today-card .today-set, .today-card > p, .today-start, .resume-card { grid-column: 1 / -1; }
  .home-activity-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .home-guides { grid-template-columns: 1fr; gap: 12px; }
  .home-guides ul { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .activity-layout { grid-template-columns: 1fr; }
  .activity-rail { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .privacy-note { grid-column: 1 / -1; }
}
@media (max-width: 600px) {
  .site-shell { width: min(100% - 1.25rem, 44rem); }
  .topbar { min-height: 64px; }
  .top-actions { gap: 6px; }
  .icon-button { min-height: 44px; min-width: 44px; padding: 7px 9px; font-size: .83rem; }
  .brand { gap: 8px; font-size: 1rem; }
  .brand-mark { width: 38px; height: 38px; border-radius: 12px; }
  .review-strip { align-items: start; font-size: .82rem; }
  .review-tag { white-space: normal; text-align: center; }
  .home-hero { gap: 14px; padding: 18px; border-radius: 20px; }
  .home-hero-copy h1 { font-size: clamp(1.9rem, 8vw, 2.45rem); }
  .home-hero-copy > p:not(.eyebrow) { font-size: .96rem; }
  .home-level { grid-template-columns: 1fr; }
  .level-choice { min-height: 57px; }
  .today-card { grid-template-columns: 1fr; padding: 17px; }
  .today-card-head, .today-card h2, .today-card .today-set, .today-card > p, .today-start, .resume-card { grid-column: auto; }
  .home-activity-grid { gap: 8px; }
  .home-activity-card { min-height: 122px; grid-template-columns: 40px minmax(0, 1fr); gap: 8px; padding: 12px 10px; }
  .home-card-icon { width: 39px; height: 39px; border-radius: 12px; font-size: .85rem; }
  .home-card-mark { display: none; }
  .home-card-copy strong { font-size: .95rem; }
  .home-card-copy > span { font-size: .82rem; }
  .home-card-copy small { font-size: .74rem; }
  .home-guides { padding: 16px; }
  .home-guides ul { grid-template-columns: 1fr; }
  .home-guide-tips ol { grid-template-columns: 1fr; }
  .catalog-title-block { align-items: start; padding: 18px; }
  .catalog-completion { min-width: 82px; padding: 10px; }
  .catalog-completion strong { font-size: 1.45rem; }
  .lesson-grid { grid-template-columns: 1fr; }
  .workbench { border-radius: 18px; }
  .workbench-head { padding: 17px 16px 0; }
  .session-progress { width: calc(100% - 32px); margin-inline: 16px; }
  .prompt { min-height: unset; margin: 13px 16px 0; font-size: clamp(1.42rem, 6vw, 1.9rem); }
  .prompt-support { margin: 7px 16px 0; font-size: .94rem; }
  .board { min-height: 210px; margin: 12px 10px 4px; padding: 12px 8px; }
  .answer-row { gap: 7px; padding: 10px 11px 0; }
  .answer-button, .move-button { min-height: 54px; }
  .answer-word { min-height: 62px; padding: 8px; font-size: .85rem; }
  .workbench-footer { padding: 12px 13px 16px; }
  .footer-actions { width: 100%; }
  .footer-actions > button { flex: 1 1 42%; }
  .compare-group { padding: 8px 5px; }
  .compare-dots { gap: 4px; min-height: 76px; }
  .compose-frame { grid-template-columns: repeat(5, minmax(31px, 44px)); gap: 5px; }
  .activity-rail { grid-template-columns: 1fr; }
  .parent-stat-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 360px) {
  .home-activity-grid { grid-template-columns: 1fr; }
  .top-actions .icon-button { padding-inline: 7px; }
  .compare-divider { font-size: .72rem; }
}