:root {
  color-scheme: light;
  --ink-950: #12172a;
  --ink-800: #232c46;
  --ink-600: #5b6579;
  --paper: #ffffff;
  --surface: #eef0f5;
  --surface-2: #f7f8fb;
  --line: #d9dee7;
  --crimson: #b1273e;
  --crimson-dark: #7d1a2c;
  --crimson-soft: #fbe2e6;
  --navy: #1c2f52;
  --navy-dark: #14213a;
  --navy-soft: #e4e9f5;
  --correct: #0f7a4d;
  --correct-bg: #e2f5ea;
  --wrong: #b1273e;
  --wrong-bg: #fbe2e6;
  --unseen: #9aa3b5;
  --unseen-soft: #edeff3;
  --shadow: 0 18px 46px rgba(18, 23, 42, 0.13);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--surface);
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink-950);
  background-color: var(--surface);
  background-image:
    linear-gradient(rgba(18, 23, 42, 0.026) 1px, transparent 1px),
    linear-gradient(90deg, rgba(18, 23, 42, 0.017) 1px, transparent 1px);
  background-size: 30px 30px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

button,
select {
  font: inherit;
}

button:focus-visible,
select:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(177, 39, 62, 0.32);
  outline-offset: 2px;
}

[hidden] {
  display: none !important;
}

.app-shell {
  width: min(100% - 28px, 920px);
  margin: 0 auto;
  padding: 22px 0 calc(34px + env(safe-area-inset-bottom));
}

.global-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
  margin: 0 2px 12px;
}

.global-nav a,
.global-nav button {
  min-height: 42px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink-800);
  background: rgba(255, 255, 255, 0.82);
  font-size: 0.88rem;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

/* ---- Home hero ---- */

.app-header {
  position: relative;
  display: flex;
  min-height: 108px;
  align-items: center;
  gap: 20px;
  overflow: hidden;
  padding: 24px 26px;
  border-radius: 24px 24px 9px 24px;
  color: #fff;
  background:
    linear-gradient(90deg, transparent 0 68%, rgba(255, 255, 255, 0.045) 68% 68.4%, transparent 68.4%),
    linear-gradient(135deg, var(--navy), var(--ink-950));
  box-shadow: var(--shadow);
}

.app-header::after {
  position: absolute;
  right: 0;
  bottom: 0;
  width: 34%;
  height: 5px;
  background: var(--crimson);
  content: "";
}

.brand-mark {
  display: grid;
  flex: 0 0 auto;
  width: 54px;
  height: 58px;
  place-items: center;
  border-radius: 9px 9px 3px 9px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  background: rgba(255, 255, 255, 0.09);
  color: #fff;
  font-size: 1.3rem;
  font-weight: 900;
}

.eyebrow {
  margin: 0 0 5px;
  color: #f3b9c2;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.13em;
}

h1 {
  margin: 0;
  font-size: clamp(1.4rem, 5vw, 1.9rem);
  line-height: 1.25;
}

h1 span {
  display: block;
  margin-top: 2px;
  color: #dfe4f3;
  font-size: 0.56em;
  font-weight: 700;
}

.home-summary {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  overflow: hidden;
  margin: 14px 0 24px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--line);
  box-shadow: 0 9px 24px rgba(18, 23, 42, 0.05);
}

.home-summary div {
  display: grid;
  gap: 4px;
  padding: 15px 17px;
  background: rgba(255, 255, 255, 0.94);
}

.home-summary span {
  color: var(--ink-600);
  font-size: 0.78rem;
  font-weight: 700;
}

.home-summary strong {
  font-size: 1.22rem;
}

.entry-grid {
  display: grid;
  gap: 14px;
}

.entry-card {
  position: relative;
  overflow: hidden;
  display: flex;
  width: 100%;
  align-items: center;
  gap: 16px;
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: 22px 22px 8px 22px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: 0 12px 32px rgba(18, 23, 42, 0.08);
  text-align: left;
  text-decoration: none;
  color: inherit;
  cursor: pointer;
}

.entry-card::before {
  position: absolute;
  inset: 0 0 auto;
  height: 5px;
  content: "";
  background: var(--navy);
}

.entry-card.is-exam::before {
  background: var(--crimson);
}

.entry-card.is-stats::before {
  background: #4d7a5f;
}

.entry-icon {
  display: grid;
  flex: 0 0 auto;
  width: 52px;
  height: 52px;
  place-items: center;
  border-radius: 15px 15px 5px 15px;
  background: var(--navy-soft);
  color: var(--navy-dark);
  font-size: 1.4rem;
  font-weight: 900;
}

.entry-card.is-exam .entry-icon {
  background: var(--crimson-soft);
  color: var(--crimson-dark);
}

.entry-card.is-stats .entry-icon {
  background: #e1efe5;
  color: #2f5c40;
}

.entry-body h2 {
  margin: 0 0 4px;
  font-size: 1.15rem;
}

.entry-body p {
  margin: 0;
  color: var(--ink-600);
  font-size: 0.86rem;
  line-height: 1.6;
}

.entry-arrow {
  margin-left: auto;
  color: var(--ink-600);
  font-size: 1.3rem;
}

/* ---- Chapter / range grid ---- */

.range-intro {
  margin: 4px 2px 14px;
  color: var(--ink-600);
  font-size: 0.88rem;
  line-height: 1.7;
}

.chapter-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 20px;
}

.chapter-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 16px 16px 6px 16px;
  background: rgba(255, 255, 255, 0.94);
  text-align: left;
  cursor: pointer;
}

.chapter-card:disabled {
  cursor: default;
  opacity: 0.55;
}

.chapter-card:not(:disabled):hover {
  border-color: var(--navy);
  background: #fff;
}

.chapter-number {
  color: var(--navy-dark);
  font-size: 0.74rem;
  font-weight: 900;
}

.chapter-title {
  font-size: 0.95rem;
  font-weight: 800;
  line-height: 1.4;
}

.chapter-status {
  margin-top: 2px;
  color: var(--ink-600);
  font-size: 0.76rem;
  font-weight: 700;
}

.chapter-card:not(:disabled) .chapter-status {
  color: var(--crimson-dark);
}

.current-range {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-left: 5px solid var(--navy);
  border-radius: 7px 14px 14px 7px;
  background: #fff;
  font-weight: 800;
}

.current-range button {
  flex: 0 0 auto;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface-2);
  font-size: 0.8rem;
  font-weight: 800;
  cursor: pointer;
}

/* ---- Quiz controls (shared with question screen) ---- */

.control-panel {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  gap: 10px;
  align-items: end;
  margin-bottom: 12px;
  padding: 15px;
  border: 1px solid var(--line);
  border-radius: 18px 18px 7px 18px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: 0 8px 28px rgba(18, 23, 42, 0.05);
}

.control-panel label {
  display: grid;
  min-width: 0;
  gap: 6px;
}

.control-panel label > span {
  padding-left: 2px;
  color: var(--ink-600);
  font-size: 0.875rem;
  font-weight: 800;
}

select {
  width: 100%;
  min-width: 0;
  min-height: 46px;
  padding: 0 38px 0 13px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink-950);
  background-color: var(--surface-2);
  background-image: linear-gradient(45deg, transparent 50%, var(--ink-800) 50%), linear-gradient(135deg, var(--ink-800) 50%, transparent 50%);
  background-position: calc(100% - 17px) 19px, calc(100% - 12px) 19px;
  background-repeat: no-repeat;
  background-size: 5px 5px, 5px 5px;
  appearance: none;
  cursor: pointer;
}

.primary-button,
.secondary-button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 10px 17px;
  border-radius: 10px 10px 4px 10px;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
  transition: transform 150ms ease, box-shadow 150ms ease, background 150ms ease;
}

.primary-button:hover,
.secondary-button:hover {
  transform: translateY(-1px);
}

.primary-button {
  border: 1px solid var(--crimson-dark);
  color: #fff;
  background: linear-gradient(135deg, var(--crimson), var(--crimson-dark));
  box-shadow: 0 8px 18px rgba(125, 26, 44, 0.22);
}

.secondary-button {
  border: 1px solid #b7bfcd;
  color: var(--ink-800);
  background: #fff;
}

.control-panel .secondary-button {
  white-space: nowrap;
}

.progress-panel {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 20px;
  align-items: center;
  margin-bottom: 12px;
  padding: 14px 18px;
  border: 1px solid var(--line);
  border-left: 5px solid var(--crimson);
  border-radius: 7px 16px 16px 7px;
  background: #fff;
}

.progress-copy {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 8px;
  color: var(--ink-800);
  font-size: 0.875rem;
  font-weight: 800;
}

.progress-track {
  height: 7px;
  overflow: hidden;
  border-radius: 999px;
  background: var(--navy-soft);
}

.progress-bar {
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--crimson), #e06478);
  transition: width 260ms ease;
}

.lifetime-stat {
  display: grid;
  min-width: 148px;
  gap: 2px;
  text-align: right;
}

.lifetime-stat span {
  color: var(--ink-600);
  font-size: 0.75rem;
}

.lifetime-stat strong {
  color: var(--crimson-dark);
  font-size: 1.22rem;
}

.quiz-card,
.state-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 22px 22px 8px 22px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.quiz-card {
  padding: clamp(22px, 5vw, 36px);
}

.question-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 17px;
}

.chapter-badge,
.topic-badge,
.difficulty-badge {
  display: inline-flex;
  min-height: 29px;
  align-items: center;
  padding: 4px 10px;
  border-radius: 7px 7px 3px 7px;
  font-size: 0.78rem;
  font-weight: 800;
}

.chapter-badge {
  color: #fff;
  background: var(--navy-dark);
}

.topic-badge {
  color: var(--crimson-dark);
  background: var(--crimson-soft);
}

.difficulty-badge {
  color: #4a5568;
  background: var(--navy-soft);
}

.question-text {
  margin: 0 0 24px;
  font-size: clamp(1.1rem, 3.6vw, 1.32rem);
  line-height: 1.7;
  letter-spacing: 0.01em;
}

.question-text:has(+ .calculation-note:not([hidden])) {
  margin-bottom: 10px;
}

.calculation-note {
  margin: 0 0 18px;
  color: var(--crimson-dark);
  font-size: 0.82rem;
  font-weight: 800;
  line-height: 1.5;
}

.choices {
  display: grid;
  gap: 11px;
}

.choice-button {
  display: grid;
  grid-template-columns: 38px 1fr;
  gap: 13px;
  width: 100%;
  min-height: 57px;
  align-items: center;
  padding: 11px 15px;
  border: 1px solid var(--line);
  border-radius: 13px 13px 5px 13px;
  color: var(--ink-950);
  background: #fff;
  text-align: left;
  line-height: 1.55;
  cursor: pointer;
  transition: border-color 150ms ease, background 150ms ease, transform 150ms ease;
}

.choice-button > .choice-text {
  min-width: 0;
  overflow-wrap: anywhere;
}

.choice-button:hover:not(:disabled) {
  border-color: var(--navy);
  background: #f7f8fc;
  transform: translateY(-1px);
}

.choice-button:disabled {
  cursor: default;
  opacity: 1;
}

.choice-key {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 8px 8px 3px 8px;
  color: var(--ink-800);
  background: var(--navy-soft);
  font-size: 0.8rem;
  font-weight: 900;
}

.choice-button.is-correct {
  border-color: rgba(15, 122, 77, 0.5);
  background: var(--correct-bg);
}

.choice-button.is-correct .choice-key {
  color: #fff;
  background: var(--correct);
}

.choice-button.is-wrong {
  border-color: rgba(177, 39, 62, 0.5);
  background: var(--wrong-bg);
}

.choice-button.is-wrong .choice-key {
  color: #fff;
  background: var(--wrong);
}

.feedback {
  margin: 24px -36px -36px;
  padding: 22px 36px 28px;
  border-top: 1px solid var(--line);
  background: var(--surface-2);
}

.feedback-result {
  margin: 0 0 6px;
  font-size: 1.05rem;
  font-weight: 900;
}

.feedback-result.correct {
  color: var(--correct);
}

.feedback-result.wrong {
  color: var(--wrong);
}

.correct-answer {
  margin: 0 0 15px;
  font-weight: 800;
  line-height: 1.6;
}

.explanation-block {
  padding: 15px 17px;
  border-left: 4px solid var(--crimson);
  border-radius: 4px 12px 12px 4px;
  background: #fff;
}

.explanation-block span {
  color: var(--crimson-dark);
  font-size: 0.8rem;
  font-weight: 900;
}

.explanation-block p {
  margin: 5px 0 0;
  line-height: 1.8;
}

.feedback .primary-button {
  width: 100%;
}

.state-card {
  padding: 40px 28px;
  text-align: center;
}

.state-card h2 {
  margin: 12px 0 7px;
  font-size: 1.35rem;
}

.state-card > p:not(.eyebrow) {
  margin: 0 auto 22px;
  color: var(--ink-600);
  line-height: 1.65;
}

.state-icon {
  display: grid;
  width: 54px;
  height: 54px;
  margin: 0 auto;
  place-items: center;
  border-radius: 12px 12px 4px 12px;
  color: #fff;
  background: var(--crimson);
  font-size: 1.5rem;
  font-weight: 900;
}

.result-eyebrow {
  color: var(--crimson-dark);
}

.result-score {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 6px;
  margin-top: 6px;
}

.result-score strong {
  color: var(--ink-950);
  font-size: clamp(3.1rem, 13vw, 4.8rem);
  line-height: 1;
}

.result-score span {
  color: var(--ink-600);
  font-size: 1.25rem;
  font-weight: 800;
}

.result-actions {
  display: flex;
  justify-content: center;
  gap: 10px;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 18px 5px 0;
  color: var(--ink-600);
  font-size: 0.78rem;
}

/* ---- Stats page ---- */

.stats-tabs {
  display: flex;
  gap: 6px;
  margin: 4px 2px 16px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
}

.stats-tab {
  flex: 1;
  min-height: 42px;
  padding: 8px 10px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--ink-600);
  font-weight: 800;
  cursor: pointer;
}

.stats-tab.is-active {
  color: #fff;
  background: linear-gradient(135deg, var(--navy), var(--ink-950));
}

.quick-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  overflow: hidden;
  margin: 0 0 16px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--line);
  box-shadow: 0 9px 24px rgba(18, 23, 42, 0.05);
}

.quick-stats article {
  display: grid;
  gap: 4px;
  padding: 15px 12px;
  background: rgba(255, 255, 255, 0.94);
}

.quick-stats span {
  color: var(--ink-600);
  font-size: 0.74rem;
  font-weight: 700;
}

.quick-stats strong {
  font-size: 1.12rem;
}

.state-unseen strong {
  color: #60737e;
}

.state-correct strong {
  color: var(--correct);
}

.state-wrong strong {
  color: var(--wrong);
}

.question-status-overview {
  margin-bottom: 16px;
  padding: 14px 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 9px 24px rgba(18, 23, 42, 0.04);
}

.question-status-track {
  display: flex;
  width: 100%;
  height: 13px;
  overflow: hidden;
  border-radius: 999px;
  background: var(--unseen-soft);
}

.question-status-track > span {
  display: block;
  height: 100%;
}

.status-correct {
  background: var(--correct);
}

.status-wrong {
  background: var(--wrong);
}

.status-unseen {
  background: var(--unseen);
}

.status-note {
  margin: 8px 0 0;
  color: var(--ink-600);
  font-size: 0.78rem;
  line-height: 1.55;
}

.dashboard-card {
  margin-bottom: 16px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 22px 22px 7px 22px;
  background: rgba(255, 255, 255, 0.93);
  box-shadow: 0 12px 36px rgba(18, 23, 42, 0.07);
}

.card-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 20px;
}

.chart-legend {
  display: flex;
  gap: 14px;
  color: var(--ink-600);
  font-size: 0.78rem;
  font-weight: 700;
}

.chart-legend span {
  display: flex;
  align-items: center;
  gap: 5px;
}

.chart-legend i {
  width: 9px;
  height: 9px;
  border-radius: 3px;
}

.legend-correct {
  background: var(--correct);
}

.legend-wrong {
  background: var(--wrong);
}

.daily-chart {
  display: grid;
  min-width: 650px;
  height: 220px;
  grid-template-columns: repeat(14, minmax(36px, 1fr));
  gap: 8px;
  align-items: end;
  overflow: hidden;
  padding: 8px 2px 0;
  border-bottom: 1px solid var(--line);
}

.daily-card {
  overflow-x: auto;
}

.daily-column {
  display: grid;
  height: 100%;
  grid-template-rows: 22px 1fr 28px;
  gap: 5px;
  align-items: end;
  text-align: center;
}

.daily-count,
.daily-label {
  color: var(--ink-600);
  font-size: 0.7rem;
  font-weight: 700;
}

.daily-bar-area {
  display: flex;
  height: 100%;
  align-items: end;
  justify-content: center;
}

.daily-stack {
  display: flex;
  width: min(100%, 30px);
  min-height: 2px;
  flex-direction: column;
  justify-content: flex-end;
  overflow: hidden;
  border-radius: 7px 7px 2px 2px;
  background: var(--correct);
}

.daily-stack.is-empty {
  background: #dfe3ea;
}

.daily-wrong {
  display: block;
  min-height: 0;
  background: var(--wrong);
}

.daily-correct {
  display: block;
  min-height: 0;
  background: var(--correct);
}

.data-note {
  margin: 13px 0 0;
  color: var(--ink-600);
  font-size: 0.8rem;
  line-height: 1.6;
}

.table-scroller {
  overflow-x: auto;
}

.range-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-variant-numeric: tabular-nums;
}

.range-table th,
.range-table td {
  padding: 13px 10px;
  border-bottom: 1px solid #e6e9f0;
  text-align: right;
  white-space: nowrap;
}

.range-table thead th {
  color: var(--ink-600);
  background: #f4f5f9;
  font-size: 0.76rem;
}

.range-table thead th:first-child {
  border-radius: 10px 0 0;
}

.range-table thead th:last-child {
  border-radius: 0 10px 0 0;
}

.range-table th:first-child {
  min-width: 190px;
  text-align: left;
}

.range-table td {
  font-size: 0.86rem;
  font-weight: 700;
}

.rate-cell {
  color: var(--crimson-dark);
  font-weight: 900 !important;
}

.unseen-cell {
  color: #60737e;
}

.correct-cell {
  color: var(--correct);
}

.wrong-cell {
  color: var(--wrong);
}

.coverage-value {
  display: grid;
  min-width: 112px;
  gap: 5px;
  text-align: right;
}

.coverage-track {
  display: flex;
  height: 5px;
  overflow: hidden;
  border-radius: 999px;
  background: #e2e6ee;
}

.coverage-track i {
  display: block;
  height: 100%;
  flex: 0 0 auto;
}

.coverage-track .coverage-correct {
  background: var(--correct);
}

.coverage-track .coverage-wrong {
  background: var(--wrong);
}

.coverage-track .coverage-unseen {
  background: var(--unseen);
}

.loading-copy {
  margin: 0;
  padding: 22px;
  border-radius: 14px;
  color: var(--ink-600);
  background: #f4f5f9;
  text-align: center;
}

@media (max-width: 760px) {
  .control-panel {
    grid-template-columns: 1fr 1fr;
  }

  .control-panel .secondary-button {
    grid-column: 1 / -1;
  }
}

@media (max-width: 560px) {
  .app-shell {
    width: min(100% - 18px, 920px);
    padding-top: 9px;
  }

  .app-header {
    min-height: auto;
    padding: 18px;
    border-radius: 18px 18px 7px 18px;
  }

  .chapter-grid {
    grid-template-columns: 1fr;
  }

  .home-summary {
    grid-template-columns: 1fr 1fr;
  }

  .progress-panel {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .lifetime-stat {
    display: flex;
    justify-content: space-between;
    text-align: left;
  }

  .quiz-card {
    padding: 21px 17px;
    border-radius: 18px 18px 6px 18px;
  }

  .choice-button {
    grid-template-columns: 34px 1fr;
    gap: 10px;
    padding: 11px 12px;
  }

  .feedback {
    margin: 22px -17px -21px;
    padding: 20px 17px 22px;
  }

  .quick-stats {
    grid-template-columns: repeat(2, 1fr);
  }

  footer {
    flex-direction: column;
    align-items: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}