.lesson-chip { padding: 7px 12px; border-radius: 999px; background: #eaf4f9; color: var(--blue); font-size: 12px; font-weight: 800; }
.sheet-hero { max-width: 1280px; min-height: calc(100vh - 82px); margin: 0 auto; padding: clamp(54px, 8vh, 100px) clamp(24px, 5vw, 74px); display: grid; grid-template-columns: 1fr minmax(390px, .88fr); align-items: center; gap: clamp(42px, 7vw, 95px); }
.sheet-hero-copy h1 { max-width: 720px; margin: 14px 0 22px; font-size: clamp(42px, 5.4vw, 74px); line-height: 1.01; letter-spacing: -.058em; }
.sheet-hero-copy > p { max-width: 650px; color: var(--muted); font-size: clamp(17px, 1.5vw, 20px); line-height: 1.72; }
.sheet-hero-copy > small { display: block; margin-top: 14px; color: var(--muted); }
.sheet-hero-visual { padding: 28px; border-radius: 28px; background: #10283f; box-shadow: 0 28px 70px rgba(16,40,63,.24); transform: rotate(-1.5deg); }
.hero-sheet { position: relative; aspect-ratio: 1.42; background: #fffdfa; box-shadow: 0 16px 35px rgba(0,0,0,.22); }
.hero-frame { position: absolute; inset: 8% 6% 8% 11%; border: 3px solid var(--ink); }
.hero-file-margin { position: absolute; top: 8%; bottom: 8%; left: 6%; border-left: 2px dashed rgba(242,103,34,.7); }
.hero-views { position: absolute; left: 24%; top: 22%; right: 38%; bottom: 30%; }
.hero-views i { position: absolute; border: 3px solid var(--ink); background: #eef6fa; }
.hero-views i:nth-child(1) { inset: 0 42% 42% 0; }
.hero-views i:nth-child(2) { inset: 63% 42% 0 0; }
.hero-views i:nth-child(3) { inset: 0 0 42% 70%; }
.hero-titleblock { position: absolute; right: 6%; bottom: 8%; width: 47%; height: 19%; border: 3px solid var(--ink); }
.hero-titleblock i { position: absolute; background: var(--ink); }
.hero-titleblock i:nth-child(1) { left: 35%; top: 0; width: 2px; height: 100%; }
.hero-titleblock i:nth-child(2) { left: 70%; top: 0; width: 2px; height: 100%; }
.hero-titleblock i:nth-child(3) { left: 0; top: 48%; width: 100%; height: 2px; }
.hero-titleblock i:nth-child(4) { left: 85%; top: 0; width: 2px; height: 48%; }
.hero-sheet > b { position: absolute; left: 13%; bottom: 10%; color: var(--orange); font-size: clamp(13px,2vw,24px); }

.sheet-shell { max-width: 1280px; margin: 0 auto; padding: 30px clamp(16px, 4vw, 54px) 90px; }
.flow-nav { position: sticky; top: 82px; z-index: 14; display: grid; grid-template-columns: repeat(7, minmax(100px,1fr)); gap: 6px; padding: 9px; margin-bottom: 18px; overflow-x: auto; border: 1px solid var(--line); border-radius: 17px; background: rgba(248,245,238,.95); backdrop-filter: blur(16px); }
.flow-nav button { min-width: 100px; min-height: 54px; padding: 8px; display: flex; align-items: center; justify-content: center; gap: 7px; border: 0; border-radius: 11px; background: transparent; cursor: pointer; }
.flow-nav button:disabled { opacity: .4; cursor: default; }
.flow-nav button:not(:disabled):hover, .flow-nav button.active { background: white; box-shadow: 0 5px 16px rgba(16,40,63,.08); }
.flow-nav button > span { width: 24px; height: 24px; flex: 0 0 auto; display: grid; place-items: center; border-radius: 50%; background: #e1ebf0; color: var(--muted); font-size: 10px; font-weight: 800; }
.flow-nav button > b { max-width: 86px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 10px; }
.flow-nav button.active > span { background: var(--orange); color: white; }
.flow-nav button.complete > span { background: var(--green); color: white; }
.flow-panel { min-height: 650px; padding: clamp(26px,5vw,58px); border: 1px solid var(--line); border-radius: 26px; background: var(--white); box-shadow: var(--shadow); }
.intro-grid { display: grid; grid-template-columns: minmax(0,1fr) 340px; gap: 55px; align-items: start; }
.intro-grid h2, .application-heading h2, .test-heading h2, .final-heading h2, .solution-heading h2 { margin: 10px 0 18px; font-size: clamp(30px,4vw,50px); line-height: 1.08; letter-spacing: -.045em; }
.intro-text p, .application-heading p, .test-heading p, .final-heading p, .solution-heading p { color: var(--muted); line-height: 1.75; }
.flow-map { padding: 25px; border-radius: 18px; background: var(--ink); color: white; }
.flow-map strong { display: block; margin-bottom: 14px; }
.flow-map ol { margin: 0; padding-left: 20px; color: #d5e0e7; font-size: 13px; line-height: 1.9; }
.flow-map b { color: white; }

.application-heading, .test-heading, .final-heading { display: grid; grid-template-columns: minmax(0,1fr) 100px; gap: 30px; align-items: start; }
.application-count, .test-heading > strong, .final-heading > strong { padding: 13px; border-radius: 15px; background: var(--ink); color: white; text-align: center; }
.application-count b, .application-count span { display: block; }
.application-count b { color: #ffad7c; font-size: 30px; line-height: 1; }
.application-count span { margin-top: 5px; color: #c5d3dd; font-size: 9px; }
.fact-strip { display: flex; flex-wrap: wrap; gap: 8px; margin: 25px 0; }
.fact-strip span { padding: 8px 11px; border: 1px solid #cfe0e9; border-radius: 9px; background: #f2f8fb; color: #31536b; font-size: 11px; font-weight: 700; }
.stage-tabs { display: grid; grid-template-columns: repeat(4,1fr); gap: 7px; margin-bottom: 14px; }
.stage-tabs span { padding: 10px; border-radius: 9px; background: #edf2f5; color: var(--muted); text-align: center; font-size: 11px; font-weight: 800; }
.stage-tabs span.active { background: #e7f4fb; color: var(--blue); box-shadow: inset 0 0 0 1px #9bc7dd; }
.stage-tabs span.done { background: #e7f7ef; color: #087b47; }
.stage-card { padding: clamp(18px,3vw,30px); border: 1px solid var(--line); border-radius: 20px; background: #fbfdfd; }
.stage-heading { display: flex; justify-content: space-between; align-items: center; gap: 20px; margin-bottom: 18px; }
.stage-heading > div { display: flex; align-items: center; gap: 12px; }
.stage-heading b, .stage-heading small { display: block; }
.stage-heading small { margin-top: 3px; color: var(--muted); font-size: 11px; }
.stage-number { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 50%; background: var(--orange); color: white; font-weight: 800; }
.compact { min-height: 38px; padding: 7px 12px; font-size: 11px; }
.target-counter { padding: 7px 10px; border-radius: 999px; background: #eaf3f7; font-size: 11px; }
.demo-board { min-height: 380px; display: grid; place-items: center; overflow: hidden; border: 1px solid var(--line); border-radius: 16px; background-color: white; background-image: linear-gradient(#edf2f4 1px,transparent 1px),linear-gradient(90deg,#edf2f4 1px,transparent 1px); background-size: 20px 20px; }
.demo-board svg { display: block; width: 100%; height: auto; max-height: 520px; }
.board-caption { margin: 12px 0 0; color: var(--muted); font-size: 12px; }
.stage-next { margin: 20px 0 0 auto; }
.drawing-prompt { margin: 0 0 16px; padding: 13px 15px; border-left: 4px solid var(--orange); background: #fff6ef; color: #6d4933; line-height: 1.6; }
.drawing-layout { display: grid; grid-template-columns: minmax(0,1fr) 260px; gap: 15px; }
.board-wrap { overflow: hidden; border: 1px solid var(--line); border-radius: 16px; background: white; }
.drawing-mobile-hint { display: none; }
.draw-board { display: block; width: 100%; height: min(58vh,540px); min-height: 390px; touch-action: none; -webkit-user-select: none; user-select: none; -webkit-touch-callout: none; cursor: crosshair; background: #e9f0f4; }
.draw-board * { touch-action: none; -webkit-user-select: none; user-select: none; -webkit-touch-callout: none; }
.board-toolbar { padding: 8px; display: flex; justify-content: flex-end; gap: 8px; border-top: 1px solid var(--line); }
.quiet-tool { width: auto; min-height: 35px; padding: 7px 11px; border: 1px solid #d5e0e6; border-radius: 8px; background: white; color: var(--muted); font-size: 10px; font-weight: 800; cursor: pointer; }
.drawing-feedback { align-self: start; padding: 20px; border: 1px solid var(--line); border-radius: 16px; background: white; }
.drawing-feedback .feedback-symbol { width: 34px; height: 34px; display: grid; place-items: center; border-radius: 50%; background: #e7f3f9; color: var(--blue); font-weight: 800; }
.drawing-feedback h3 { margin: 12px 0 7px; font-size: 16px; }
.drawing-feedback p { color: var(--muted); font-size: 12px; line-height: 1.55; }
.drawing-feedback ul { margin: 15px 0 0; padding: 0; list-style: none; }
.drawing-feedback li { padding: 8px 0; border-top: 1px solid #edf1f3; color: var(--muted); font-size: 11px; }
.drawing-feedback li::before { content: "○"; margin-right: 7px; }
.drawing-feedback li.done { color: #087b47; }
.drawing-feedback li.done::before { content: "✓"; }
.drawing-feedback.success { border-color: rgba(22,168,100,.4); background: #f2fbf6; }
.drawing-feedback.error { border-color: rgba(217,70,69,.32); background: #fff7f7; }
.drawing-feedback.neutral { background: #f7fafb; }
.paper-outline { fill: #fffdfa; stroke: var(--ink); stroke-width: 3; }
.paper-frame { fill: none; stroke: #a8bac5; stroke-width: 2; }
.paper-label { fill: var(--muted); font-size: 16px; font-weight: 800; font-family: Manrope,sans-serif; }
.paper-note { fill: #738798; font-size: 12px; font-weight: 600; font-family: Manrope,sans-serif; }
.ghost-shape { fill: none; stroke: #78aeca; stroke-width: 4; stroke-dasharray: 10 8; opacity: .42; }
.ghost-point { fill: var(--orange); opacity: .72; }
.user-shape { fill: none; stroke: var(--ink); stroke-width: 5; stroke-linecap: round; stroke-linejoin: round; }
.preview-shape { fill: none; stroke: var(--orange); stroke-width: 4; stroke-dasharray: 7 7; }
.demo-shape { fill: none; stroke: var(--blue); stroke-width: 5; stroke-linecap: round; stroke-linejoin: round; stroke-dasharray: 1700; stroke-dashoffset: 1700; animation: draw-demo .9s ease forwards; }
@keyframes draw-demo { to { stroke-dashoffset: 0; } }
.topic-question-card > .primary-button { display: flex; }
.final-warning { margin: 0 0 20px; padding: 13px 16px; display: flex; gap: 12px; border-radius: 11px; background: #fff3e9; color: #6c4630; font-size: 12px; }
.final-warning b { color: var(--orange); }
.solution-heading { max-width: 860px; }
.solution-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin: 30px 0; }
.solution-card { overflow: hidden; border: 1px solid var(--line); border-radius: 18px; background: white; }
.solution-card header { padding: 17px; display: flex; justify-content: space-between; gap: 12px; }
.solution-card header h3 { margin: 0; font-size: 16px; }
.solution-card header strong { color: var(--green); }
.solution-card svg { display: block; width: 100%; height: auto; background: #fbfdfe; border-top: 1px solid var(--line); }
.solution-card p { margin: 0; padding: 14px 17px; color: var(--muted); font-size: 11px; line-height: 1.6; }
.result-metrics { max-width: 850px; margin: 0 auto 30px; display: grid; grid-template-columns: repeat(3,1fr); gap: 12px; }
.result-metrics article { padding: 18px; border: 1px solid var(--line); border-radius: 14px; text-align: center; }
.result-metrics span, .result-metrics strong { display: block; }
.result-metrics span { color: var(--muted); font-size: 10px; }
.result-metrics strong { margin-top: 6px; font-size: 25px; }

@media (max-width: 920px) {
  .sheet-hero { grid-template-columns: 1fr 360px; }
  .flow-nav { top: 70px; grid-template-columns: repeat(7,112px); }
  .intro-grid, .drawing-layout { grid-template-columns: 1fr; }
  .flow-map { max-width: 560px; }
  .drawing-feedback { display: grid; grid-template-columns: 40px 1fr; gap: 0 9px; }
  .drawing-feedback h3 { margin-top: 4px; }
  .drawing-feedback p, .drawing-feedback ul { grid-column: 2; }
}
@media (max-width: 760px) {
  .sheet-hero { min-height: auto; display: flex; flex-direction: column; padding-top: 42px; }
  .sheet-hero-copy { order: 2; }
  .sheet-hero-visual { order: 1; width: min(480px,100%); }
  .sheet-shell { padding: 12px 10px 60px; }
  .flow-panel { min-height: 0; padding: 22px 15px; border-radius: 18px; }
  .application-heading, .test-heading, .final-heading { grid-template-columns: 1fr; }
  .application-count, .test-heading > strong, .final-heading > strong { width: 90px; }
  .stage-tabs { overflow-x: auto; grid-template-columns: repeat(4,120px); }
  .solution-grid { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  .lesson-chip { display: none; }
  .sheet-shell { padding-right: 6px; padding-left: 6px; }
  .flow-panel { padding-right: 10px; padding-left: 10px; }
  .stage-card { padding: 11px; }
  .drawing-mobile-hint { display: block; margin: 0; padding: 9px 11px; border-bottom: 1px solid var(--line); background: #eef7fb; color: var(--ink); font-size: 12px; line-height: 1.45; }
  .sheet-hero { padding-left: 18px; padding-right: 18px; }
  .sheet-hero-copy h1 { font-size: 38px; }
  .sheet-hero-visual { padding: 16px; border-radius: 20px; }
  .demo-board { min-height: 275px; }
  .draw-board { min-height: 330px; height: 56vh; }
  .stage-heading { align-items: flex-start; }
  .stage-heading .compact { flex: 0 0 auto; }
  .final-warning { flex-direction: column; gap: 3px; }
  .result-metrics { grid-template-columns: 1fr; }
}