:root {
  --ink: #142033;
  --muted: #708096;
  --paper: #f5f7fb;
  --card: #ffffff;
  --line: #e4e9f1;
  --blue: #3157d5;
  --blue-deep: #1c328d;
  --mint: #dff4ec;
  --mint-ink: #18785e;
  --coral: #ff745d;
  --shadow: 0 16px 44px rgba(34, 53, 92, .11);
}

* { box-sizing: border-box; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif; }
button { font: inherit; cursor: pointer; }
.topbar { min-height: 84px; padding: calc(16px + env(safe-area-inset-top)) max(5vw, env(safe-area-inset-right)) 16px max(5vw, env(safe-area-inset-left)); background: #0b1220; color: white; display: flex; align-items: center; gap: 16px; }
.brand-mark { width: 49px; height: 49px; border: 1px solid rgba(255,255,255,.35); border-radius: 14px; display: grid; place-items: center; font-weight: 900; font-size: 16px; letter-spacing: -.09em; color: white; background: transparent; cursor: pointer; }
.brand-mark span { color: #ffc56c; margin-left: 2px; }
.eyebrow, .kicker { margin: 0 0 4px; color: #8e9db8; font-size: 10px; font-weight: 800; letter-spacing: .18em; }
.topbar h1 { margin: 0; font-size: 17px; letter-spacing: .04em; }
.topbar-meta { margin-left: auto; display: flex; align-items: center; gap: 8px; color: #c3cce0; font-size: 12px; }
.status-dot { width: 7px; height: 7px; border-radius: 50%; background: #76dbb6; box-shadow: 0 0 0 4px rgba(118,219,182,.12); }
.app-shell { min-height: calc(100vh - 131px); max-width: 1240px; margin: 0 auto; padding: 58px 28px 70px; }
.screen { animation: appear .35s ease both; }
.hidden { display: none !important; }
.start-screen { min-height: 600px; display: grid; grid-template-columns: 1.05fr .95fr; align-items: center; gap: 70px; position: relative; }
.hero-copy h2, .result-header h2 { margin: 16px 0 18px; font-size: clamp(37px, 5.2vw, 68px); line-height: 1.13; letter-spacing: -.06em; }
.hero-copy h2 em { color: var(--blue); font-style: normal; }
.lead { margin: 0; max-width: 540px; color: var(--muted); font-size: 16px; line-height: 1.9; }
.start-panel { padding: 35px; background: var(--card); border: 1px solid var(--line); border-radius: 24px; box-shadow: var(--shadow); }
.exam-facts { display: grid; grid-template-columns: repeat(3, 1fr); border-bottom: 1px solid var(--line); padding-bottom: 25px; margin-bottom: 24px; }
.exam-facts div + div { border-left: 1px solid var(--line); padding-left: 22px; }
.exam-facts strong { display: block; font-size: 35px; letter-spacing: -.06em; }
.exam-facts span { color: var(--muted); font-size: 12px; }
.start-note { display: flex; gap: 12px; color: var(--muted); font-size: 13px; line-height: 1.7; }
.start-note p { margin: 0 0 26px; }
.note-icon { width: 23px; height: 23px; flex: 0 0 auto; border-radius: 50%; display: grid; place-items: center; background: var(--mint); color: var(--mint-ink); font-weight: 800; }
.mode-label { margin: 0 0 10px; color: var(--muted); font-size: 11px; font-weight: 800; letter-spacing: .1em; }
.exam-select { display: block; width: 100%; min-height: 48px; margin-bottom: 18px; padding: 8px 38px 8px 12px; border: 1px solid var(--line); border-radius: 11px; background: #fbfcfe; color: var(--ink); font: inherit; font-size: 13px; font-weight: 800; }
.exam-select:focus { outline: 3px solid rgba(76, 95, 220, .18); border-color: var(--blue); }
.exam-modes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-bottom: 18px; }
.mode-button { min-height: 66px; padding: 9px 6px; border: 1px solid var(--line); border-radius: 11px; background: #fbfcfe; color: var(--ink); text-align: left; }
.mode-button strong, .mode-button span { display: block; }
.mode-button strong { font-size: 13px; }
.mode-button span { margin-top: 4px; color: var(--muted); font-size: 10px; }
.mode-button.selected { border: 2px solid var(--blue); background: #eef1ff; }
.mode-button.selected strong { color: var(--blue-deep); }
.primary-button, .secondary-button { min-height: 48px; border-radius: 12px; padding: 0 20px; border: 0; font-weight: 800; transition: transform .18s, box-shadow .18s, background .18s; }
.primary-button { color: white; background: var(--blue); box-shadow: 0 8px 18px rgba(49,87,213,.23); }
.primary-button:hover { background: var(--blue-deep); transform: translateY(-2px); box-shadow: 0 12px 22px rgba(49,87,213,.29); }
.primary-button span { margin-left: 12px; font-size: 20px; vertical-align: -1px; }
.secondary-button { color: var(--ink); border: 1px solid var(--line); background: white; }
.secondary-button:hover { border-color: #b9c5da; background: #f8faff; }
.fig-start-button { width: 100%; margin-top: 10px; }
.fig-start-button span { margin-left: 8px; color: var(--blue); }
.fig-screen { max-width: 760px; margin: 0 auto; }
.fig-header { text-align: center; }
.fig-header h2 { margin: 16px 0 10px; font-size: clamp(38px, 6vw, 66px); letter-spacing: -.07em; }
.fig-header .lead { margin: auto; }
.fig-toolbar { display: flex; justify-content: space-between; align-items: center; margin: 34px 0 12px; color: var(--muted); font-size: 12px; font-weight: 800; }
.fig-card { width: 100%; min-height: 330px; padding: 38px 24px; border: 1px solid var(--line); border-radius: 24px; background: white; box-shadow: var(--shadow); color: var(--ink); text-align: center; }
.fig-card:hover { border-color: #aab8ea; }
.fig-card-label { display: block; color: var(--muted); font-size: 11px; font-weight: 800; letter-spacing: .16em; }
.fig-card strong { display: block; margin: 52px 0 44px; font-size: clamp(56px, 13vw, 130px); line-height: 1; letter-spacing: .02em; }
.fig-meaning { display: block; min-height: 24px; color: #a4afc0; font-size: 15px; font-weight: 800; }
.fig-meaning.visible { color: var(--blue-deep); }
.fig-actions { display: flex; gap: 10px; justify-content: center; margin-top: 18px; }
.fig-actions button { min-width: 120px; }
.text-button { display: block; margin: 24px auto 0; border: 0; background: transparent; color: var(--blue); font-weight: 800; cursor: pointer; }
.text-button:hover { text-decoration: underline; }
.source-note { position: absolute; bottom: 0; color: #99a6b9; font-size: 11px; line-height: 1.7; }
.source-note p { margin: 0; }
.source-note p + p { margin-top: 4px; color: #aab5c5; }
.source-note a { color: var(--blue); font-weight: 800; text-decoration: none; }
.source-note a:hover { text-decoration: underline; }
.exam-toolbar { display: flex; align-items: end; gap: 28px; margin-bottom: 25px; }
.progress-wrap { flex: 1; }
.progress-label { display: flex; justify-content: space-between; margin-bottom: 9px; color: var(--muted); font-size: 12px; font-weight: 700; }
.progress-track { overflow: hidden; height: 7px; background: #e6ebf3; border-radius: 8px; }
.progress-bar { height: 100%; width: 2%; background: linear-gradient(90deg, var(--blue), #6d83f0); border-radius: inherit; transition: width .25s; }
.diagram-link { display: inline-block; margin-top: 8px; color: var(--blue); font-size: 11px; font-weight: 800; text-decoration: none; }
.diagram-link:hover { text-decoration: underline; }
.timer { min-width: 116px; padding: 11px 14px; border: 1px solid var(--line); border-radius: 12px; background: white; color: var(--blue-deep); font-variant-numeric: tabular-nums; font-weight: 800; text-align: center; }
.timer-icon { margin-right: 7px; color: var(--coral); }
.exam-layout { display: grid; grid-template-columns: 230px minmax(0, 1fr); gap: 24px; align-items: start; }
.diagram-panel { display: none; }
.wiring-layout .exam-layout { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
.wiring-layout .question-nav { display: none; }
.wiring-layout .diagram-panel { display: block; grid-column: 1; grid-row: 1; position: sticky; top: 20px; min-width: 0; padding: 16px; background: white; border: 1px solid var(--line); border-radius: 18px; box-shadow: var(--shadow); }
.wiring-layout .question-card { grid-column: 2; grid-row: 1; }
.wiring-layout .question-image-frame { grid-template-columns: 1fr; }
.diagram-panel-heading { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; color: var(--ink); font-size: 12px; font-weight: 800; }
.diagram-panel-heading a { color: var(--blue); font-size: 11px; text-decoration: none; }
.diagram-panel-heading a:hover { text-decoration: underline; }
.diagram-intro-image { display: block; width: 100%; height: auto; max-height: 230px; object-fit: contain; object-position: top center; margin-bottom: 10px; background: #fafbfd; }
.diagram-panel img { display: block; width: 100%; height: calc(100vh - 105px); min-height: 420px; object-fit: contain; object-position: top center; background: #fafbfd; }
.diagram-panel .diagram-intro-image { height: auto; min-height: 0; }
.question-nav { padding: 18px; background: white; border: 1px solid var(--line); border-radius: 18px; position: sticky; top: 20px; }
.nav-heading, .review-heading { display: flex; justify-content: space-between; align-items: center; }
.nav-heading { margin-bottom: 15px; font-weight: 800; font-size: 13px; }
.nav-heading span:last-child { color: var(--muted); font-size: 11px; font-weight: 600; }
.question-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; }
.question-number { height: 32px; border: 1px solid var(--line); border-radius: 8px; background: #fbfcfe; color: #7c899e; font-size: 11px; font-weight: 700; }
.question-number.current { border-color: var(--blue); background: var(--blue); color: white; }
.question-number.answered:not(.current) { border-color: #a8ddca; background: var(--mint); color: var(--mint-ink); }
.nav-legend { display: flex; gap: 10px; margin-top: 17px; color: var(--muted); font-size: 10px; }
.nav-legend span { display: flex; gap: 5px; align-items: center; }
.nav-legend i { width: 8px; height: 8px; border-radius: 3px; background: var(--mint); }
.nav-legend .legend-current { background: var(--blue); }
.question-card { overflow: hidden; background: white; border: 1px solid var(--line); border-radius: 22px; box-shadow: var(--shadow); }
.question-card.wrong-state { border-color: var(--coral); box-shadow: 0 0 0 4px rgba(255,116,93,.10), var(--shadow); }
.question-card.wrong-state .question-image-frame { background: #fffaf8; }
.question-meta { display: flex; justify-content: space-between; padding: 19px 24px; border-bottom: 1px solid var(--line); color: var(--muted); font-size: 12px; font-weight: 800; }
.question-meta span:last-child { color: var(--blue); }
.question-image-frame { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 16px; padding: 23px; background: #fafbfd; min-height: 250px; }
.problem-panel { min-width: 0; }
.problem-panel > span { display: block; margin: 0 0 8px 2px; color: var(--muted); font-size: 10px; font-weight: 800; letter-spacing: .12em; }
.question-image-frame img { display: block; width: 100%; height: auto; object-fit: contain; object-position: top center; border: 1px solid #e8edf4; background: white; }
.answer-area { padding: 23px 24px 10px; }
.answer-label { margin: 0 0 12px; color: var(--muted); font-size: 11px; font-weight: 800; letter-spacing: .1em; }
.answer-options { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.answer-option { min-height: 52px; border: 1px solid var(--line); border-radius: 12px; background: #fbfcfe; color: var(--ink); font-size: 17px; font-weight: 800; }
.answer-option:hover { border-color: #9eafe8; background: #f4f6ff; }
.answer-option.selected { border: 2px solid var(--blue); background: #eef1ff; color: var(--blue-deep); }
.answer-option.wrong-selected { border-color: var(--coral); background: #fff0ed; color: #c44b38; }
.answer-feedback { display: none; margin: 12px 0 0; color: var(--coral); font-size: 12px; font-weight: 800; }
.answer-feedback.visible { display: block; }
.hint-button { margin-top: 14px; padding: 7px 12px; border: 1px solid #b8c4ed; border-radius: 999px; background: #f5f7ff; color: var(--blue-deep); font-size: 11px; font-weight: 800; }
.hint-button:hover { background: #eaf0ff; }
.explanation-panel { display: none; margin-top: 12px; padding: 13px 15px; border-left: 3px solid var(--blue); border-radius: 8px; background: #f5f7ff; color: #53627a; font-size: 12px; line-height: 1.7; }
.explanation-panel.visible { display: block; }
.explanation-panel strong { color: var(--blue-deep); }
.explanation-panel p { margin: 5px 0 0; }
.question-actions { display: flex; justify-content: space-between; gap: 12px; padding: 18px 24px 24px; }
.result-screen { max-width: 960px; margin: 0 auto; }
.result-header { text-align: center; }
.result-header h2 { font-size: clamp(35px, 5vw, 56px); margin-bottom: 12px; }
.result-header .lead { margin: auto; }
.result-grid { display: grid; grid-template-columns: 1fr 1.4fr; gap: 18px; margin: 38px 0 45px; }
.score-card, .result-stats { min-height: 190px; padding: 27px; background: white; border: 1px solid var(--line); border-radius: 20px; }
.score-card { position: relative; overflow: hidden; }
.score-card > span { color: var(--muted); font-size: 12px; font-weight: 800; }
.score-card strong { display: block; margin-top: 9px; font-size: 60px; letter-spacing: -.08em; }
.score-card small { color: var(--muted); }
.score-card em { display: block; margin-top: 5px; color: var(--muted); font-size: 11px; font-style: normal; }
.score-ring { position: absolute; right: 27px; top: 31px; width: 104px; height: 104px; border-radius: 50%; background: conic-gradient(var(--blue) 0deg, #e8edf5 0deg); display: grid; place-items: center; }
.score-ring div { width: 80px; height: 80px; border-radius: 50%; background: white; }
.result-stats { display: grid; grid-template-columns: repeat(4, 1fr); align-items: center; }
.result-stats div + div { border-left: 1px solid var(--line); padding-left: 24px; }
.result-stats span { display: block; color: var(--muted); font-size: 12px; }
.result-stats strong { display: block; margin-top: 10px; font-size: 27px; }
.review-heading { margin-bottom: 15px; }
.review-heading h3 { margin: 0; font-size: 20px; }
.review-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.review-item { display: flex; align-items: center; gap: 14px; padding: 13px 15px; border: 1px solid var(--line); border-radius: 13px; background: white; }
.review-item.correct { border-left: 4px solid var(--mint-ink); }
.review-item.incorrect { border-left: 4px solid var(--coral); }
.review-q { min-width: 42px; font-weight: 900; }
.review-answer { flex: 1; color: var(--muted); font-size: 12px; }
.review-answer strong { color: var(--ink); }
.review-explanation { display: block; margin-top: 7px; color: #53627a; font-size: 11px; line-height: 1.6; }
.review-badge { font-size: 11px; font-weight: 800; }
.correct .review-badge { color: var(--mint-ink); }
.incorrect .review-badge { color: var(--coral); }
footer { min-height: 47px; padding: 0 max(5vw, env(safe-area-inset-right)) env(safe-area-inset-bottom) max(5vw, env(safe-area-inset-left)); display: flex; justify-content: space-between; align-items: center; border-top: 1px solid var(--line); color: #93a0b3; font-size: 10px; letter-spacing: .05em; }
@keyframes appear { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
@media (max-width: 850px) { .start-screen { grid-template-columns: 1fr; gap: 35px; padding-bottom: 45px; } .source-note { position: static; } .exam-layout { grid-template-columns: 1fr; } .question-nav { position: static; order: 2; } .question-grid { grid-template-columns: repeat(10, 1fr); } .question-card { order: 1; } .result-grid { grid-template-columns: 1fr; } }
@media (max-width: 900px) { .wiring-layout .exam-layout { grid-template-columns: 1fr; } .wiring-layout .diagram-panel { grid-column: 1; grid-row: 1; position: static; } .wiring-layout .question-card { grid-column: 1; grid-row: 2; } .diagram-panel img { height: auto; max-height: 70vh; } }
@media (max-width: 560px) { .topbar { padding: calc(13px + env(safe-area-inset-top)) max(18px, env(safe-area-inset-right)) 13px max(18px, env(safe-area-inset-left)); } .topbar-meta { display: none; } .app-shell { padding: 32px 14px calc(50px + env(safe-area-inset-bottom)); } .start-panel { padding: 24px; } .hero-copy h2 { font-size: 41px; } .exam-toolbar { gap: 12px; } .timer { min-width: 100px; } .question-image-frame { grid-template-columns: 1fr; gap: 18px; padding: 10px; min-height: 190px; } .answer-area, .question-actions { padding-left: 14px; padding-right: 14px; } .question-actions { flex-wrap: wrap; } .question-actions button { flex: 1; } .review-list { grid-template-columns: 1fr; } .result-stats { grid-template-columns: repeat(2, 1fr); padding: 20px 15px; gap: 14px 0; } .result-stats div + div { padding-left: 12px; } .result-stats strong { font-size: 21px; } }