/* ===== Design Tokens ===== */
:root {
  --color-primary: #0B2545;
  --color-primary-soft: #1d3b66;
  --color-accent: #F2C14E;
  --color-accent-deep: #d89d1f;
  --color-bg: #F7F9FC;
  --color-bg-card: #ffffff;
  --color-text: #1a2438;
  --color-text-muted: #5b6478;
  --color-border: #e3e8f0;
  --color-success: #2d8a52;
  --color-danger: #c2384a;
  --shadow-sm: 0 1px 2px rgba(11, 37, 69, 0.06), 0 1px 4px rgba(11, 37, 69, 0.04);
  --shadow-md: 0 4px 12px rgba(11, 37, 69, 0.08), 0 2px 6px rgba(11, 37, 69, 0.05);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --font-sans: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", "Meiryo", system-ui, sans-serif;
  --container-max: 980px;
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-primary); text-decoration-color: var(--color-accent); text-decoration-thickness: 2px; text-underline-offset: 3px; }
a:hover { color: var(--color-accent-deep); }

/* ===== Layout ===== */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Header (site-wide) ===== */
.site-header {
  background: var(--color-primary);
  color: #fff;
  padding: 14px 0;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.site-header__brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: #fff;
  text-decoration: none;
}
.site-header__brand-mark {
  width: 36px; height: 36px;
  border-radius: 8px;
  background: var(--color-accent);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 18px;
}
.site-header__title { font-size: 15px; font-weight: 600; line-height: 1.3; }
.site-header__subtitle { font-size: 12px; color: #c4d2e8; line-height: 1.3; }
.site-nav { display: flex; gap: 20px; align-items: center; flex-wrap: wrap; }
.site-nav a { color: #d5dcea; text-decoration: none; font-size: 14px; font-weight: 500; }
.site-nav a:hover { color: var(--color-accent); }

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-soft) 100%);
  color: #fff;
  padding: 64px 0 80px;
  position: relative;
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  right: -80px; top: -80px;
  width: 320px; height: 320px;
  background: var(--color-accent);
  opacity: 0.18;
  border-radius: 50%;
}
.hero__eyebrow {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-primary);
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 16px;
}
.hero__title {
  font-size: clamp(28px, 4.5vw, 44px);
  font-weight: 700;
  line-height: 1.3;
  margin: 0 0 16px;
  position: relative;
  z-index: 2;
}
.hero__lead {
  font-size: 16px;
  line-height: 1.85;
  max-width: 720px;
  color: #d5dcea;
  position: relative;
  z-index: 2;
}
.hero__meta {
  margin-top: 24px;
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  font-size: 13px;
  color: #aabbd2;
  position: relative;
  z-index: 2;
}
.hero__meta span strong { color: #fff; font-weight: 600; }

/* ===== Sections ===== */
.section { padding: 56px 0; }
.section--alt { background: #fff; }
.section__title {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0 0 8px;
  display: flex;
  align-items: baseline;
  gap: 12px;
}
.section__title::before {
  content: "";
  width: 24px;
  height: 4px;
  background: var(--color-accent);
  border-radius: 2px;
  display: inline-block;
}
.section__desc {
  color: var(--color-text-muted);
  margin: 0 0 32px;
  max-width: 720px;
}

/* ===== Week Grid ===== */
.week-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}
.week-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
  text-decoration: none;
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
  position: relative;
}
.week-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-accent);
  color: var(--color-text);
}
.week-card__num {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-accent-deep);
  letter-spacing: 0.06em;
}
.week-card__title {
  font-size: 16px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--color-primary);
  margin: 0;
}
.week-card__instructor {
  font-size: 12px;
  color: var(--color-text-muted);
  margin-top: auto;
}
.week-card__tag {
  display: inline-block;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--color-bg);
  color: var(--color-text-muted);
  align-self: flex-start;
}
.week-card[data-type="exam"] .week-card__tag { background: #fde8eb; color: var(--color-danger); }
.week-card[data-type="practice"] .week-card__tag { background: #e6f3ec; color: var(--color-success); }
.week-card[data-instructor="takagi"] { opacity: 0.7; }
.week-card[data-instructor="takagi"]::after {
  content: "高木先生担当";
  position: absolute;
  top: 12px; right: 12px;
  font-size: 10px;
  color: var(--color-text-muted);
}

/* ===== Week Page Layout ===== */
.week-hero {
  background: var(--color-primary);
  color: #fff;
  padding: 40px 0 48px;
}
.week-hero__num {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-primary);
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 13px;
  font-weight: 700;
  margin-bottom: 16px;
}
.week-hero__title {
  font-size: clamp(24px, 4vw, 36px);
  font-weight: 700;
  margin: 0 0 12px;
  line-height: 1.35;
}
.week-hero__lead {
  color: #d5dcea;
  margin: 0;
  max-width: 720px;
  line-height: 1.85;
}
.week-hero__meta {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  margin-top: 24px;
  font-size: 13px;
  color: #aabbd2;
}
.week-hero__meta strong { color: #fff; font-weight: 600; margin-left: 6px; }

.week-body { padding: 48px 0 80px; }
.week-section { margin-bottom: 56px; }
.week-section__head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-border);
}
.week-section__num {
  background: var(--color-primary);
  color: #fff;
  width: 32px; height: 32px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-size: 14px;
  font-weight: 700;
  flex-shrink: 0;
}
.week-section__title {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0;
  line-height: 1.4;
}
.week-section__time {
  margin-left: auto;
  font-size: 12px;
  color: var(--color-text-muted);
  background: var(--color-bg);
  padding: 4px 10px;
  border-radius: 999px;
  flex-shrink: 0;
}

.prose { line-height: 1.85; }
.prose p { margin: 0 0 16px; }
.prose h4 { font-size: 17px; color: var(--color-primary); margin: 28px 0 12px; }
.prose ul, .prose ol { padding-left: 1.6em; margin: 0 0 16px; }
.prose li { margin-bottom: 6px; }

/* ===== Callout ===== */
.callout {
  background: #fff;
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 24px 0;
}
.callout__label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-accent-deep);
  margin-bottom: 6px;
  text-transform: uppercase;
}
.callout__title {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0 0 8px;
}
.callout--info { border-left-color: var(--color-primary); }
.callout--info .callout__label { color: var(--color-primary); }
.callout--warn { border-left-color: var(--color-danger); }
.callout--warn .callout__label { color: var(--color-danger); }

/* ===== Quiz ===== */
.quiz {
  background: linear-gradient(135deg, #fff8e6 0%, #fffaf0 100%);
  border: 1px solid #f0d896;
  border-radius: var(--radius-md);
  padding: 24px;
  margin: 24px 0;
}
.quiz__label {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-primary);
  padding: 3px 10px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 700;
  margin-bottom: 10px;
}
.quiz__q {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0 0 16px;
  line-height: 1.55;
}
.quiz__choices { display: flex; flex-direction: column; gap: 10px; margin-bottom: 16px; }
.quiz__choice {
  background: #fff;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  font-family: inherit;
  font-size: 15px;
  text-align: left;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-text);
}
.quiz__choice:hover { border-color: var(--color-accent); }
.quiz__choice[data-state="correct"] {
  background: #eaf6ee;
  border-color: var(--color-success);
  color: #1a5a37;
}
.quiz__choice[data-state="wrong"] {
  background: #fce8ec;
  border-color: var(--color-danger);
  color: #781a26;
}
.quiz__choice[data-state="disabled"] { opacity: 0.5; cursor: default; }
.quiz__choice-mark {
  width: 24px; height: 24px;
  border-radius: 50%;
  background: var(--color-bg);
  color: var(--color-text-muted);
  display: grid; place-items: center;
  font-size: 12px; font-weight: 700;
  flex-shrink: 0;
}
.quiz__choice[data-state="correct"] .quiz__choice-mark { background: var(--color-success); color: #fff; }
.quiz__choice[data-state="wrong"] .quiz__choice-mark { background: var(--color-danger); color: #fff; }
.quiz__feedback {
  background: #fff;
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.7;
  display: none;
}
.quiz__feedback.is-shown { display: block; }

/* ===== Interactive box (Google Forms / group work) ===== */
.interactive {
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin: 24px 0;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  align-items: center;
}
.interactive__label {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-primary);
  padding: 3px 10px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 700;
  margin-bottom: 10px;
  letter-spacing: 0.04em;
}
.interactive__title {
  font-size: 17px;
  font-weight: 700;
  margin: 0 0 8px;
  line-height: 1.5;
}
.interactive__desc {
  font-size: 14px;
  color: #c4d2e8;
  margin: 0 0 12px;
  line-height: 1.75;
}
.interactive__qr {
  width: 110px;
  height: 110px;
  background: #fff;
  border-radius: 8px;
  display: grid;
  place-items: center;
  color: var(--color-primary);
  font-size: 11px;
  text-align: center;
  padding: 6px;
}
.interactive__meta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 12px;
  color: #aabbd2;
  margin-top: 8px;
}
.interactive__meta code {
  background: rgba(255,255,255,0.12);
  padding: 2px 8px;
  border-radius: 4px;
  font-family: "SFMono-Regular", Consolas, monospace;
  color: #fff;
}

/* ===== Agenda ===== */
.agenda {
  border-left: 3px solid var(--color-accent);
  padding-left: 20px;
  margin: 24px 0;
}
.agenda__item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 16px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--color-border);
}
.agenda__item:last-child { border-bottom: none; }
.agenda__time {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-accent-deep);
  font-variant-numeric: tabular-nums;
}
.agenda__body { font-size: 14px; }
.agenda__title { font-weight: 600; color: var(--color-primary); display: block; }
.agenda__note { font-size: 12px; color: var(--color-text-muted); margin-top: 2px; }

/* ===== Pager (prev/next) ===== */
.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 56px;
}
.pager__btn {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  text-decoration: none;
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: border-color 0.15s, transform 0.15s;
}
.pager__btn:hover { border-color: var(--color-accent); transform: translateY(-1px); color: var(--color-text); }
.pager__btn-label { font-size: 11px; color: var(--color-text-muted); letter-spacing: 0.06em; }
.pager__btn-title { font-size: 14px; font-weight: 600; color: var(--color-primary); }
.pager__btn--next { text-align: right; }

/* ===== Footer ===== */
.site-footer {
  background: var(--color-primary);
  color: #aabbd2;
  padding: 32px 0;
  font-size: 13px;
}
.site-footer a { color: #d5dcea; }

/* ===== Utilities ===== */
.muted { color: var(--color-text-muted); }
.small { font-size: 13px; }
.center { text-align: center; }
@media (max-width: 640px) {
  .interactive { grid-template-columns: 1fr; }
  .interactive__qr { margin: 0 auto; }
  .agenda__item { grid-template-columns: 1fr; gap: 4px; }
  .pager { grid-template-columns: 1fr; }
  .week-hero__meta { gap: 12px; }
}