/* ============================================================
   ポップでかわいい学習サイト スタイル
   色：ピンク × 紫 × ミント × イエロー
   ============================================================ */

:root {
  --pink: #FF6B9D;
  --pink-soft: #FFE4EF;
  --purple: #A855F7;
  --purple-soft: #F3E8FF;
  --yellow: #FFD60A;
  --yellow-soft: #FFFBE6;
  --mint: #06D6A0;
  --mint-soft: #D4FFF1;
  --cyan: #4CC9F0;
  --bg: #FFF5F7;
  --text: #1A1A2E;
  --text-soft: #5B5B7A;
  --card: #FFFFFF;
  --radius: 20px;
  --radius-sm: 12px;
  --shadow-soft: 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-pop: 0 8px 24px rgba(255, 107, 157, 0.20);
  --shadow-purple: 0 8px 24px rgba(168, 85, 247, 0.20);
  --gradient-primary: linear-gradient(135deg, #FF6B9D 0%, #A855F7 100%);
  --gradient-accent: linear-gradient(135deg, #FFD60A 0%, #06D6A0 100%);
  --gradient-cool: linear-gradient(135deg, #4CC9F0 0%, #A855F7 100%);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: 'M PLUS Rounded 1c', system-ui, -apple-system, "Hiragino Kaku Gothic ProN", sans-serif;
  background: var(--bg);
  background-image:
    radial-gradient(circle at 10% 20%, rgba(255, 107, 157, 0.08), transparent 40%),
    radial-gradient(circle at 90% 80%, rgba(168, 85, 247, 0.08), transparent 40%);
  color: var(--text);
  line-height: 1.8;
  min-height: 100vh;
  font-weight: 400;
}

.container { max-width: 1000px; margin: 0 auto; padding: 0 20px; }

/* ============================================================
   Header
   ============================================================ */

#site-header {
  background: var(--gradient-primary);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 4px 16px rgba(255, 107, 157, 0.25);
}

#site-header nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  max-width: 1000px;
  margin: 0 auto;
}

.logo {
  font-size: 22px;
  font-weight: 900;
  color: #fff;
  text-decoration: none;
  letter-spacing: 0.5px;
}

.logo:hover { transform: scale(1.05); transition: transform 0.2s; }

.progress-nav {
  background: rgba(255, 255, 255, 0.25);
  backdrop-filter: blur(10px);
  color: #fff;
  padding: 8px 18px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 14px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* ============================================================
   Hero
   ============================================================ */

.hero {
  padding: 80px 20px 60px;
  text-align: center;
  position: relative;
}

.hero h1 {
  font-size: clamp(32px, 6vw, 60px);
  font-weight: 900;
  line-height: 1.25;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 20px;
  letter-spacing: -0.5px;
}

.hero-sub {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--text-soft);
  margin-bottom: 40px;
  font-weight: 700;
}

.cta {
  display: inline-block;
  padding: 18px 44px;
  background: var(--gradient-primary);
  color: #fff;
  font-weight: 900;
  font-size: 18px;
  text-decoration: none;
  border-radius: 999px;
  box-shadow: var(--shadow-pop);
  transition: transform 0.2s, box-shadow 0.2s;
  border: none;
  cursor: pointer;
  font-family: inherit;
}

.cta:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 12px 32px rgba(255, 107, 157, 0.35);
}

.cta.mint { background: linear-gradient(135deg, #06D6A0 0%, #4CC9F0 100%); box-shadow: 0 8px 24px rgba(6, 214, 160, 0.30); }
.cta.mint:hover { box-shadow: 0 12px 32px rgba(6, 214, 160, 0.45); }

/* ============================================================
   Stats
   ============================================================ */

.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 16px;
  padding: 0 20px;
  margin-bottom: 60px;
}

.stat-pill {
  background: var(--card);
  border-radius: var(--radius);
  padding: 24px 20px;
  text-align: center;
  box-shadow: var(--shadow-soft);
}

.stat-value {
  font-size: 32px;
  font-weight: 900;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat-label {
  font-size: 13px;
  color: var(--text-soft);
  font-weight: 700;
  margin-top: 4px;
}

/* ============================================================
   Phase Cards
   ============================================================ */

.section-title {
  font-size: clamp(24px, 4vw, 32px);
  font-weight: 900;
  text-align: center;
  margin: 60px 20px 40px;
  color: var(--text);
}

.section-title .accent {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.phases-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  padding: 0 20px;
  margin-bottom: 60px;
}

.phase-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow-soft);
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  position: relative;
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  display: block;
}

.phase-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-pop);
}

.phase-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background: var(--phase-color, var(--gradient-primary));
}

.phase-card .phase-emoji {
  font-size: 56px;
  line-height: 1;
  margin-bottom: 12px;
}

.phase-num {
  color: var(--purple);
  font-weight: 900;
  font-size: 11px;
  letter-spacing: 2.5px;
}

.phase-card .phase-title {
  font-size: 20px;
  font-weight: 900;
  margin: 4px 0 10px;
  line-height: 1.4;
}

.phase-desc {
  color: var(--text-soft);
  font-size: 14px;
  font-weight: 400;
  margin-bottom: 18px;
  line-height: 1.6;
}

.phase-meta {
  display: flex;
  gap: 14px;
  font-size: 12px;
  color: var(--text-soft);
  font-weight: 700;
  flex-wrap: wrap;
}

.phase-progress {
  margin-top: 16px;
  height: 10px;
  background: #F3F3F8;
  border-radius: 5px;
  overflow: hidden;
  position: relative;
}

.phase-progress-fill {
  height: 100%;
  background: var(--gradient-accent);
  border-radius: 5px;
  transition: width 0.4s ease;
}

.phase-progress-text {
  font-size: 11px;
  color: var(--mint);
  font-weight: 900;
  margin-top: 6px;
}

/* ============================================================
   How It Works
   ============================================================ */

.how-section {
  background: var(--card);
  margin: 60px 20px;
  padding: 40px 28px;
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.how-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  margin-top: 30px;
}

.how-step {
  text-align: center;
  padding: 20px;
}

.how-step-num {
  display: inline-block;
  width: 48px;
  height: 48px;
  line-height: 48px;
  border-radius: 50%;
  background: var(--gradient-primary);
  color: #fff;
  font-weight: 900;
  font-size: 20px;
  margin-bottom: 12px;
}

.how-step-title {
  font-weight: 900;
  margin-bottom: 8px;
}

.how-step-desc {
  font-size: 14px;
  color: var(--text-soft);
}

/* ============================================================
   Markdown Body
   ============================================================ */

.markdown-body {
  background: var(--card);
  padding: 48px 40px;
  border-radius: var(--radius);
  margin: 20px;
  box-shadow: var(--shadow-soft);
  font-weight: 400;
}

.markdown-body > *:first-child { margin-top: 0; }

.markdown-body h1 {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 900;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 24px;
  line-height: 1.3;
  letter-spacing: -0.3px;
}

.markdown-body h2 {
  font-size: clamp(22px, 3vw, 28px);
  color: var(--purple);
  margin: 40px 0 16px;
  padding-bottom: 10px;
  border-bottom: 3px solid var(--purple-soft);
  font-weight: 900;
}

.markdown-body h3 {
  font-size: 20px;
  color: var(--pink);
  margin: 28px 0 12px;
  font-weight: 900;
}

.markdown-body h4 {
  font-size: 17px;
  color: var(--text);
  margin: 20px 0 8px;
  font-weight: 900;
}

.markdown-body p {
  margin: 14px 0;
  color: var(--text);
  font-weight: 400;
}

.markdown-body ul,
.markdown-body ol {
  margin: 14px 0 14px 28px;
  color: var(--text);
}

.markdown-body li {
  margin: 8px 0;
}

.markdown-body li::marker {
  color: var(--purple);
  font-weight: 900;
}

.markdown-body code {
  background: var(--pink-soft);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.88em;
  color: #D1006B;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-weight: 700;
}

.markdown-body pre {
  background: #1A1A2E;
  color: #E8E8F0;
  padding: 22px;
  border-radius: var(--radius-sm);
  overflow-x: auto;
  margin: 18px 0;
  font-size: 0.92em;
  box-shadow: var(--shadow-soft);
}

.markdown-body pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  font-weight: 400;
}

.markdown-body table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 18px 0;
  background: #FFF;
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: var(--shadow-soft);
}

.markdown-body th,
.markdown-body td {
  padding: 14px 16px;
  text-align: left;
  border-bottom: 1px solid #F3F3F8;
}

.markdown-body th {
  background: var(--gradient-primary);
  color: #fff;
  font-weight: 900;
  font-size: 14px;
}

.markdown-body tr:last-child td { border-bottom: none; }

.markdown-body tr:hover td { background: var(--pink-soft); }

.markdown-body blockquote {
  border-left: 5px solid var(--yellow);
  padding: 16px 22px;
  margin: 18px 0;
  background: var(--yellow-soft);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text);
  font-weight: 700;
}

.markdown-body a {
  color: var(--purple);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-color: var(--purple-soft);
  text-underline-offset: 3px;
}

.markdown-body a:hover {
  color: var(--pink);
  text-decoration-color: var(--pink);
}

.markdown-body hr {
  border: none;
  height: 3px;
  background: var(--gradient-accent);
  border-radius: 2px;
  margin: 32px 0;
  opacity: 0.4;
}

.markdown-body strong { font-weight: 900; color: var(--text); }

.markdown-body img { max-width: 100%; border-radius: var(--radius-sm); margin: 16px 0; }

/* ============================================================
   Assignment Cards
   ============================================================ */

.assignments-list {
  padding: 0 20px;
  margin-bottom: 40px;
}

.assignments-title {
  font-size: 24px;
  font-weight: 900;
  margin: 40px 20px 20px;
  color: var(--purple);
}

.assignment-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 18px 22px;
  margin: 10px 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-soft);
  transition: all 0.2s;
  text-decoration: none;
  color: inherit;
}

.assignment-card:hover {
  transform: translateX(6px);
  box-shadow: var(--shadow-pop);
}

.assignment-card.done {
  background: linear-gradient(135deg, #D4FFF1 0%, #E8F7FF 100%);
}

.assignment-check {
  width: 32px;
  height: 32px;
  border: 3px solid var(--purple);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  background: #fff;
  cursor: pointer;
  flex-shrink: 0;
  transition: all 0.2s;
  font-size: 16px;
}

.assignment-check:hover { transform: scale(1.1); }

.assignment-card.done .assignment-check {
  background: var(--mint);
  border-color: var(--mint);
  color: #fff;
  animation: pop 0.3s ease;
}

@keyframes pop {
  0% { transform: scale(1); }
  50% { transform: scale(1.3); }
  100% { transform: scale(1); }
}

.assignment-info { flex: 1; }

.assignment-num {
  color: var(--purple);
  font-weight: 900;
  font-size: 11px;
  letter-spacing: 1.5px;
}

.assignment-title {
  font-weight: 700;
  font-size: 16px;
  margin-top: 2px;
}

.assignment-card.done .assignment-title {
  text-decoration: line-through;
  color: var(--text-soft);
}

.assignment-arrow {
  color: var(--purple);
  font-size: 20px;
}

/* ============================================================
   Breadcrumb
   ============================================================ */

.breadcrumb {
  padding: 20px;
  font-size: 14px;
  color: var(--text-soft);
  font-weight: 700;
}

.breadcrumb a {
  color: var(--purple);
  text-decoration: none;
  font-weight: 700;
}

.breadcrumb a:hover { color: var(--pink); }

.breadcrumb .sep { margin: 0 8px; color: var(--text-soft); }

/* ============================================================
   Loader
   ============================================================ */

.loader {
  text-align: center;
  padding: 80px 20px;
  font-size: 48px;
  animation: bounce 1s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* ============================================================
   Prev/Next Nav
   ============================================================ */

.nav-buttons {
  display: flex;
  justify-content: space-between;
  padding: 40px 20px;
  gap: 16px;
}

.nav-button {
  flex: 1;
  padding: 20px 24px;
  background: var(--card);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  box-shadow: var(--shadow-soft);
  transition: transform 0.2s, box-shadow 0.2s;
  display: block;
}

.nav-button:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-pop);
}

.nav-button .label {
  font-size: 11px;
  color: var(--purple);
  font-weight: 900;
  letter-spacing: 1.5px;
  margin-bottom: 4px;
}

.nav-button .nav-body {
  font-size: 15px;
  line-height: 1.4;
}

.nav-button.placeholder { visibility: hidden; }

/* ============================================================
   Complete Button (Assignment Page)
   ============================================================ */

.complete-zone {
  text-align: center;
  padding: 40px 20px;
  background: var(--card);
  margin: 20px;
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.complete-zone h3 {
  font-weight: 900;
  margin-bottom: 16px;
  color: var(--text);
}

.complete-zone.done h3 { color: var(--mint); }

.complete-zone .helper {
  font-size: 13px;
  color: var(--text-soft);
  margin-top: 12px;
}

/* ============================================================
   Footer
   ============================================================ */

footer {
  padding: 60px 20px 40px;
  text-align: center;
  color: var(--text-soft);
  font-size: 14px;
  margin-top: 40px;
}

footer p { margin: 4px 0; }

.footer-small { font-size: 12px; opacity: 0.7; }

/* ============================================================
   Cases Link Card
   ============================================================ */

.sidebar-card {
  background: var(--gradient-cool);
  color: #fff;
  margin: 20px;
  padding: 28px 24px;
  border-radius: var(--radius);
  text-align: center;
  box-shadow: var(--shadow-purple);
}

.sidebar-card h3 {
  font-size: 20px;
  font-weight: 900;
  margin-bottom: 8px;
  color: #fff;
}

.sidebar-card p { font-size: 14px; margin-bottom: 16px; font-weight: 700; }

.sidebar-card .btn-white {
  display: inline-block;
  padding: 10px 24px;
  background: #fff;
  color: var(--purple);
  border-radius: 999px;
  text-decoration: none;
  font-weight: 900;
  font-size: 14px;
}

/* ============================================================
   Mobile
   ============================================================ */

@media (max-width: 640px) {
  .hero { padding: 60px 20px 40px; }
  .markdown-body { padding: 28px 20px; margin: 20px 12px; }
  .markdown-body h1 { font-size: 26px; }
  .markdown-body h2 { font-size: 21px; }
  .markdown-body h3 { font-size: 17px; }
  .nav-buttons { flex-direction: column; }
  .how-section { margin: 40px 12px; padding: 28px 20px; }
  .phases-grid { padding: 0 12px; }
  .assignments-list { padding: 0 12px; }
  #site-header nav { padding: 12px 16px; }
  .logo { font-size: 18px; }
  .progress-nav { font-size: 12px; padding: 6px 12px; }
}