/* ==========================================================================
   Python初心者向け学習サイト - 共通スタイルシート
   ========================================================================== */

:root {
  --color-primary: #3498db;
  --color-primary-dark: #2980b9;
  --color-secondary: #2c3e50;
  --color-bg: #f8f9fa;
  --color-bg-light: #ffffff;
  --color-success: #27ae60;
  --color-error: #e74c3c;
  --color-warning: #f39c12;
  --color-code-bg: #2c3e50;
  --color-code-text: #ecf0f1;
  --color-border: #e1e4e8;
  --color-text-muted: #6c7a89;

  --font-base: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic",
    Meiryo, system-ui, -apple-system, sans-serif;
  --font-code: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

  --radius: 10px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --header-height: 64px;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-base);
  background-color: var(--color-bg);
  color: var(--color-secondary);
  line-height: 1.7;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

ul,
ol {
  padding-left: 1.4em;
}

button {
  font-family: inherit;
}

/* アクセシビリティ: キーボードフォーカス表示 */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: 0;
  top: -50px;
  background: var(--color-secondary);
  color: #fff;
  padding: 10px 16px;
  z-index: 1000;
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 0;
}

/* ---------- レイアウト共通 ---------- */
.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- ヘッダー ---------- */
.site-header {
  background-color: var(--color-bg-light);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  min-height: var(--header-height);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
  gap: 16px;
}

.site-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-secondary);
  white-space: nowrap;
}
.site-logo:hover {
  text-decoration: none;
  color: var(--color-primary);
}
.site-logo .logo-accent {
  color: var(--color-primary);
}

.nav-toggle {
  display: none;
  min-width: 44px;
  min-height: 44px;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 1.4rem;
  cursor: pointer;
}

.main-nav {
  display: flex;
}

.main-nav ul {
  list-style: none;
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0;
}

.main-nav a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 0 14px;
  border-radius: 8px;
  color: var(--color-secondary);
  font-weight: 500;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  background-color: rgba(52, 152, 219, 0.12);
  color: var(--color-primary-dark);
  text-decoration: none;
}

/* ---------- パンくずリスト ---------- */
.breadcrumb {
  padding: 14px 0;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
.breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0;
}
.breadcrumb li + li::before {
  content: "›";
  margin-right: 6px;
  color: var(--color-text-muted);
}
.breadcrumb a {
  color: var(--color-text-muted);
}
.breadcrumb [aria-current="page"] {
  color: var(--color-secondary);
  font-weight: 600;
}

/* ---------- ヒーロー ---------- */
.hero {
  padding: 56px 0;
  text-align: center;
  background: linear-gradient(180deg, #eaf4fc 0%, var(--color-bg) 100%);
}
.hero h1 {
  font-size: clamp(1.7rem, 4vw, 2.6rem);
  margin: 0 0 16px;
  color: var(--color-secondary);
}
.hero p {
  max-width: 640px;
  margin: 0 auto 28px;
  color: var(--color-text-muted);
  font-size: 1.05rem;
}
.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ---------- ボタン ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 22px;
  border-radius: 8px;
  border: 2px solid transparent;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: background-color 0.15s ease, transform 0.1s ease;
}
.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}
.btn-primary {
  background-color: var(--color-primary);
  color: #fff;
}
.btn-primary:hover {
  background-color: var(--color-primary-dark);
  color: #fff;
}
.btn-outline {
  background-color: transparent;
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.btn-outline:hover {
  background-color: rgba(52, 152, 219, 0.1);
}
.btn-sm {
  min-height: 36px;
  padding: 0 14px;
  font-size: 0.9rem;
}

/* ---------- セクション共通 ---------- */
main {
  min-height: 60vh;
}
.section {
  padding: 48px 0;
}
.section-title {
  font-size: 1.6rem;
  margin-bottom: 8px;
  color: var(--color-secondary);
}
.section-lead {
  color: var(--color-text-muted);
  margin-bottom: 32px;
}

/* ---------- カテゴリ概要カード（トップページ） ---------- */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}
.category-card {
  background: var(--color-bg-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.15s ease, transform 0.15s ease;
}
.category-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.category-card h3 {
  margin: 0 0 8px;
  color: var(--color-primary-dark);
}
.category-card p {
  margin: 0 0 14px;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* ---------- ツールバー（検索・フィルタ） ---------- */
.toolbar {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 28px;
}
.toolbar .search-field {
  flex: 1 1 260px;
  position: relative;
}
.toolbar input[type="search"],
.toolbar select {
  width: 100%;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 1rem;
  background-color: var(--color-bg-light);
  color: var(--color-secondary);
}
.filter-chips {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.filter-chip {
  min-height: 40px;
  padding: 0 16px;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background: var(--color-bg-light);
  color: var(--color-secondary);
  cursor: pointer;
  font-size: 0.9rem;
}
.filter-chip[aria-pressed="true"] {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.result-count {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

/* ---------- レッスン一覧カード ---------- */
.lesson-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}
.lesson-card {
  background: var(--color-bg-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: relative;
}
.lesson-card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 8px;
}
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  white-space: nowrap;
}
.badge-category {
  background: rgba(52, 152, 219, 0.15);
  color: var(--color-primary-dark);
}
.badge-difficulty-初級 {
  background: rgba(39, 174, 96, 0.15);
  color: var(--color-success);
}
.badge-difficulty-中級 {
  background: rgba(243, 156, 18, 0.18);
  color: #a3660a;
}
.badge-difficulty-上級 {
  background: rgba(231, 76, 60, 0.15);
  color: var(--color-error);
}
.lesson-card h3 {
  margin: 0;
  font-size: 1.1rem;
}
.lesson-card p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.92rem;
  flex: 1;
}
.lesson-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ---------- レッスン詳細 ---------- */
.lesson-detail-header {
  margin-bottom: 24px;
}
.lesson-detail-header h1 {
  font-size: clamp(1.4rem, 3vw, 2rem);
  margin: 10px 0;
}
.lesson-meta {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 6px;
}

.lesson-body {
  background: var(--color-bg-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  margin-bottom: 24px;
}
.lesson-body h3 {
  color: var(--color-secondary);
  margin-top: 0;
}
.lesson-body :is(h2, h3, h4) {
  scroll-margin-top: calc(var(--header-height) + 16px);
}

.code-block-wrapper {
  position: relative;
  margin: 18px 0;
}
pre.code-block {
  background: var(--color-code-bg);
  color: var(--color-code-text);
  padding: 18px 20px;
  border-radius: 8px;
  overflow-x: auto;
  font-family: var(--font-code);
  font-size: 0.92rem;
  line-height: 1.6;
}
pre.code-block code {
  font-family: var(--font-code);
}
.tok-kw {
  color: #f68fce;
  font-weight: 600;
}
.tok-str {
  color: #a5e075;
}
.tok-com {
  color: #8593a0;
  font-style: italic;
}
.tok-num {
  color: #f7b955;
}
.code-copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  min-height: 36px;
  padding: 0 12px;
  background: rgba(255, 255, 255, 0.12);
  color: var(--color-code-text);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.8rem;
}
.code-copy-btn:hover {
  background: rgba(255, 255, 255, 0.22);
}

.code-explanation {
  background: rgba(52, 152, 219, 0.08);
  border-left: 4px solid var(--color-primary);
  padding: 14px 18px;
  border-radius: 0 8px 8px 0;
  margin: 16px 0;
}

.hint,
.warning,
.note {
  padding: 14px 18px;
  border-radius: 8px;
  margin: 16px 0;
  font-size: 0.95rem;
}
.hint {
  background: rgba(39, 174, 96, 0.1);
  border-left: 4px solid var(--color-success);
}
.warning {
  background: rgba(243, 156, 18, 0.12);
  border-left: 4px solid var(--color-warning);
}
.note {
  background: rgba(44, 62, 80, 0.06);
  border-left: 4px solid var(--color-secondary);
}

.practice-box {
  background: #fff9ec;
  border: 1px dashed var(--color-warning);
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 24px;
}
.practice-box h3 {
  margin-top: 0;
}
.answer-panel {
  margin-top: 14px;
}
.answer-panel[hidden] {
  display: none;
}

.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin: 32px 0;
}

.related-lessons {
  margin-top: 24px;
}
.related-lessons ul {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.related-lessons a {
  display: inline-block;
  padding: 8px 16px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: var(--color-bg-light);
}
.related-lessons a:hover {
  background: rgba(52, 152, 219, 0.1);
  text-decoration: none;
}

/* ---------- エラー辞典 / メソッド辞典 ---------- */
.dict-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.dict-entry {
  background: var(--color-bg-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}
.dict-entry > summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 22px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 1.05rem;
}
.dict-entry > summary::-webkit-details-marker {
  display: none;
}
.dict-entry > summary::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--color-primary);
  flex-shrink: 0;
  width: 24px;
  text-align: center;
}
.dict-entry[open] > summary::after {
  content: "−";
}
.dict-entry-body {
  padding: 0 22px 22px;
}
.dict-entry-body dt {
  font-weight: 700;
  margin-top: 14px;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.dict-entry-body dt:first-child {
  margin-top: 0;
}
.dict-entry-body dd {
  margin: 4px 0 0;
}
.dict-entry-body ul {
  margin: 4px 0 0;
}

/* ---------- フッター ---------- */
.site-footer {
  background: var(--color-secondary);
  color: #cfd8e3;
  padding: 40px 0;
  margin-top: 60px;
}
.site-footer a {
  color: #9dc4e0;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 24px;
  margin-bottom: 24px;
}
.footer-grid h4 {
  color: #fff;
  margin: 0 0 12px;
  font-size: 0.95rem;
}
.footer-grid ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.9rem;
}
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.15);
  padding-top: 18px;
  font-size: 0.85rem;
  color: #9aa7b5;
  text-align: center;
}

/* ---------- 広告スロット ---------- */
.ad-slot {
  margin: 32px 0;
  text-align: center;
  min-height: 90px;
}
.ad-slot-label {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-bottom: 4px;
  letter-spacing: 0.05em;
}
.ad-slot-items {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 16px;
}
.ad-slot-item {
  display: inline-block;
}

/* ---------- ユーティリティ（インラインstyle属性を使わずCSPを厳格に保つため） ---------- */
.section-tight-top {
  padding-top: 16px;
}
.mb-8 {
  margin-bottom: 8px;
}

/* ---------- 空状態 ---------- */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-muted);
}

/* ==========================================================================
   レスポンシブ
   ========================================================================== */
@media (max-width: 768px) {
  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-bg-light);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    display: none;
    flex-direction: column;
    padding: 12px 20px 20px;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
  }
  .main-nav.is-open {
    display: flex;
  }
  .main-nav ul {
    flex-direction: column;
    width: 100%;
  }
  .main-nav a {
    width: 100%;
  }
  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }
  .lesson-nav {
    flex-direction: column;
  }
  .lesson-nav .btn {
    width: 100%;
  }
}

@media (max-width: 576px) {
  .hero {
    padding: 40px 0;
  }
  .section {
    padding: 32px 0;
  }
  .lesson-body,
  .practice-box {
    padding: 18px;
  }
}

/* ==========================================================================
   ダークモード
   ========================================================================== */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #5dade2;
    --color-primary-dark: #85c1e9;
    --color-secondary: #ecf0f1;
    --color-bg: #14181c;
    --color-bg-light: #1f2429;
    --color-border: #333a40;
    --color-text-muted: #a0aab4;
    --color-code-bg: #0f1317;
  }
  .hero {
    background: linear-gradient(180deg, #1a222a 0%, var(--color-bg) 100%);
  }
  .practice-box {
    background: #241f14;
  }
  .code-explanation {
    background: rgba(93, 173, 226, 0.1);
  }
}

/* ==========================================================================
   印刷
   ========================================================================== */
@media print {
  .site-header,
  .site-footer,
  .ad-slot,
  .toolbar,
  .nav-toggle {
    display: none !important;
  }
}