/*
Theme Name: Brain Journal
Theme URI: https://brain-journal.com
Author: たくまる
Author URI: https://brain-journal.com
Description: 脳卒中看護を、もっと身近に。もっと楽しく。
Version: 1.0.0
License: GNU General Public License v2 or later
Text Domain: brain-journal
*/

/* ============================================================
   Brain Journal - Style Sheet
   脳卒中看護学習サイトのメインスタイル
   ============================================================ */

/* ============================================================
   1. CSS変数（カラーパレット・フォント・サイズ）
   ============================================================ */
:root {
  /* カラー */
  --color-bg-deep:   #0d1b2a;
  --color-navy:      #1a2e4a;
  --color-teal:      #00d4d4;
  --color-teal-dark: #009999;
  --color-coral:     #ff6b6b;
  --color-bg:        #f0f4f8;
  --color-white:     #ffffff;
  --color-text:      #1a202c;
  --color-text-mute: #64748b;

  /* フォント */
  --font-heading: 'Montserrat', 'Noto Sans JP', sans-serif;
  --font-body:    'Noto Sans JP', sans-serif;

  /* スペーシング */
  --section-padding: 5rem 1.5rem;
  --card-radius: 12px;
  --transition: 0.3s ease;
}

/* ============================================================
   2. リセット・ベーススタイル
   ============================================================ */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

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

/* ============================================================
   3. ユーティリティ
   ============================================================ */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section-label {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-teal);
  margin-bottom: 0.75rem;
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--color-text-mute);
  max-width: 600px;
}

/* フェードイン（スクロールアニメーション用） */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-in.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 遅延クラス */
.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }

/* ============================================================
   4. ヘッダー・ナビゲーション
   ============================================================ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(13, 27, 42, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0, 212, 212, 0.1);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ロゴ */
.site-logo {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: 0.02em;
}

.site-logo .logo-accent {
  color: var(--color-teal);
}

/* デスクトップナビ */
.nav-links {
  display: none;
  gap: 2rem;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.7);
  transition: color var(--transition);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-teal);
  transition: width var(--transition);
}

.nav-links a:hover,
.nav-links a.active,
.nav-links a[aria-current="page"] {
  color: var(--color-white);
}

.nav-links a:hover::after,
.nav-links a.active::after,
.nav-links a[aria-current="page"]::after {
  width: 100%;
}

/* ハンバーガーメニューボタン */
.hamburger {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-white);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ハンバーガー開閉アニメーション */
.hamburger.is-open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger.is-open span:nth-child(2) {
  opacity: 0;
}

.hamburger.is-open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* モバイルメニュー */
.mobile-menu {
  display: none;
  position: fixed;
  top: 64px;
  left: 0;
  width: 100%;
  background: rgba(13, 27, 42, 0.98);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  padding: 2rem 1.5rem;
  border-bottom: 1px solid rgba(0, 212, 212, 0.15);
}

.mobile-menu.is-open {
  display: block;
}

.mobile-menu a {
  display: block;
  padding: 0.75rem 0;
  font-size: 1rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.8);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  transition: color var(--transition);
}

.mobile-menu a:last-child {
  border-bottom: none;
}

.mobile-menu a:hover,
.mobile-menu a.active {
  color: var(--color-teal);
}

/* 640px以上でデスクトップナビ表示 */
@media (min-width: 640px) {
  .nav-links {
    display: flex;
  }
  .hamburger {
    display: none;
  }
}

/* ============================================================
   5. ヒーローセクション（トップページ）
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--color-bg-deep) 0%, var(--color-navy) 100%);
  overflow: hidden;
  padding: 6rem 1.5rem 4rem;
}

/* 微細なドットパターン背景 */
.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: radial-gradient(rgba(0, 212, 212, 0.07) 1px, transparent 1px);
  background-size: 30px 30px;
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3rem;
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
}

/* ヒーロー左カラム（テキスト） */
.hero-text {
  text-align: center;
}

.hero-label {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-teal);
  margin-bottom: 1.25rem;
  opacity: 0;
  animation: fadeSlideUp 0.8s 0.2s forwards;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.5rem, 7vw, 4rem);
  font-weight: 700;
  color: var(--color-white);
  line-height: 1.15;
  margin-bottom: 1.5rem;
  opacity: 0;
  animation: fadeSlideUp 0.8s 0.4s forwards;
}

.hero-title .title-brain {
  color: var(--color-white);
}

.hero-title .title-journal {
  color: var(--color-teal);
}

.hero-catchcopy {
  font-size: clamp(1.125rem, 2.5vw, 1.375rem);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.5rem;
  opacity: 0;
  animation: fadeSlideUp 0.8s 0.6s forwards;
}

.hero-subcopy {
  font-size: clamp(0.9rem, 2vw, 1.05rem);
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: 2rem;
  opacity: 0;
  animation: fadeSlideUp 0.8s 0.8s forwards;
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  opacity: 0;
  animation: fadeSlideUp 0.8s 1s forwards;
}

/* ヒーロー右カラム（SVG） */
.hero-visual {
  width: 100%;
  max-width: 400px;
  opacity: 0;
  animation: fadeIn 1.2s 0.6s forwards;
}

.hero-visual svg {
  width: 100%;
  height: auto;
}

/* 640px以上で横並び */
@media (min-width: 640px) {
  .hero-inner {
    flex-direction: row;
    justify-content: space-between;
  }

  .hero-text {
    text-align: left;
    flex: 1;
    max-width: 560px;
  }

  .hero-buttons {
    justify-content: flex-start;
  }

  .hero-visual {
    flex: 0 0 40%;
    max-width: 420px;
  }
}

/* 神経ネットワークSVGのアニメーション */
.nerve-line {
  stroke: var(--color-teal);
  stroke-width: 1;
  opacity: 0.4;
  animation: nervePulse 3s ease-in-out infinite;
}

.nerve-line:nth-child(odd) {
  animation-delay: 0.5s;
}

.nerve-line:nth-child(3n) {
  animation-delay: 1s;
}

.nerve-node {
  fill: var(--color-teal);
  opacity: 0.6;
  animation: nodePulse 4s ease-in-out infinite;
}

.nerve-node:nth-child(even) {
  animation-delay: 1.5s;
}

.nerve-node:nth-child(3n + 1) {
  animation-delay: 0.8s;
}

.nerve-node-core {
  fill: var(--color-teal);
  opacity: 0.9;
  animation: nodePulse 3s ease-in-out infinite;
}

@keyframes nervePulse {
  0%, 100% { opacity: 0.25; }
  50%      { opacity: 0.7; }
}

@keyframes nodePulse {
  0%, 100% { opacity: 0.4; }
  50%      { opacity: 0.9; }
}

@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* ============================================================
   6. ボタン
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.75rem;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 700;
  border-radius: 50px;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-teal);
  color: var(--color-bg-deep);
}

.btn-primary:hover {
  background: var(--color-teal-dark);
  box-shadow: 0 0 24px rgba(0, 212, 212, 0.4);
  transform: translateY(-2px);
}

.btn-secondary {
  background: transparent;
  color: var(--color-white);
  border: 1.5px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
  border-color: var(--color-teal);
  color: var(--color-teal);
  box-shadow: 0 0 16px rgba(0, 212, 212, 0.2);
  transform: translateY(-2px);
}

/* ライトモード用ボタン */
.btn-outline {
  background: transparent;
  color: var(--color-teal-dark);
  border: 1.5px solid var(--color-teal-dark);
}

.btn-outline:hover {
  background: var(--color-teal-dark);
  color: var(--color-white);
  box-shadow: 0 0 20px rgba(0, 212, 212, 0.3);
  transform: translateY(-2px);
}

/* 小さめボタン（カード内など） */
.btn-sm {
  padding: 0.5rem 1.25rem;
  font-size: 0.8rem;
}

/* ============================================================
   7. コンセプトセクション
   ============================================================ */
.concept {
  padding: var(--section-padding);
  background: var(--color-white);
}

.concept-header {
  text-align: center;
  margin-bottom: 3rem;
}

.concept-header .section-title {
  color: var(--color-text);
}

.concept-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 640px) {
  .concept-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 960px) {
  .concept-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* コンセプトカード */
.concept-card {
  background: var(--color-white);
  border: 1px solid #e2e8f0;
  border-radius: var(--card-radius);
  padding: 2rem 1.75rem;
  position: relative;
  overflow: hidden;
  transition: all var(--transition);
}

/* 左ボーダーのアクセント */
.concept-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  border-radius: 4px 0 0 4px;
}

.concept-card:nth-child(1)::before {
  background: var(--color-teal);
}

.concept-card:nth-child(2)::before {
  background: var(--color-coral);
}

.concept-card:nth-child(3)::before {
  background: #fbbf24;
}

.concept-card:hover {
  border-color: transparent;
  box-shadow: 0 8px 32px rgba(0, 212, 212, 0.12), 0 0 0 1px rgba(0, 212, 212, 0.15);
  transform: translateY(-4px);
}

.concept-icon {
  width: 48px;
  height: 48px;
  margin-bottom: 1.25rem;
}

.concept-icon svg {
  width: 100%;
  height: 100%;
}

.concept-card h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--color-text);
}

.concept-card p {
  font-size: 0.9rem;
  color: var(--color-text-mute);
  line-height: 1.75;
}

/* ============================================================
   8. 最新記事セクション
   ============================================================ */
.latest-articles {
  padding: var(--section-padding);
  background: var(--color-bg);
}

.latest-articles-header {
  text-align: center;
  margin-bottom: 3rem;
}

.articles-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 640px) {
  .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 960px) {
  .articles-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* 記事カード */
.article-card {
  background: var(--color-white);
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1);
  transform: translateY(-4px);
}

/* サムネイルエリア（グラデーション） */
.card-thumbnail {
  height: 150px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.card-thumbnail-basics {
  background: linear-gradient(135deg, #0d1b2a 0%, #1a4a6a 100%);
}

.card-thumbnail-symptom {
  background: linear-gradient(135deg, #1a2e4a 0%, #00d4d4 100%);
}

.card-thumbnail-case {
  background: linear-gradient(135deg, #2d1b4e 0%, #ff6b6b 100%);
}

/* アイキャッチ画像がある場合のサムネイル */
.card-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.card-thumbnail-icon {
  font-size: 2.5rem;
  opacity: 0.3;
  color: var(--color-white);
}

/* カテゴリタグ（サムネイル上に重ねて表示） */
.card-category-overlay {
  position: absolute;
  bottom: 12px;
  left: 12px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.75rem;
  border-radius: 50px;
  color: var(--color-white);
}

.tag-basics {
  background: rgba(0, 212, 212, 0.8);
}

.tag-symptom {
  background: rgba(26, 46, 74, 0.8);
}

.tag-case {
  background: rgba(255, 107, 107, 0.8);
}

/* カテゴリスラッグに対応するタグ色 */
.tag-category-basics,
[class*="tag-"][class*="basics"] {
  background: rgba(0, 212, 212, 0.8);
}

.card-body {
  padding: 1.25rem 1.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.card-body h3 {
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 0.75rem;
  color: var(--color-text);
}

.card-body .card-excerpt {
  font-size: 0.85rem;
  color: var(--color-text-mute);
  line-height: 1.7;
  margin-bottom: 1.25rem;
  flex: 1;
}

.card-body .btn-sm {
  align-self: flex-start;
}

/* ============================================================
   9. ページヒーロー（archive / page）
   ============================================================ */
.page-hero {
  padding: 8rem 1.5rem 3rem;
  background: linear-gradient(135deg, var(--color-bg-deep) 0%, var(--color-navy) 100%);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: radial-gradient(rgba(0, 212, 212, 0.06) 1px, transparent 1px);
  background-size: 30px 30px;
  pointer-events: none;
}

.page-hero .section-title {
  color: var(--color-white);
  position: relative;
  z-index: 1;
}

.page-hero .section-subtitle {
  color: rgba(255, 255, 255, 0.6);
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

/* ============================================================
   10. カテゴリフィルター（archive.php）
   ============================================================ */
.filter-section {
  padding: 3rem 1.5rem 1rem;
  background: var(--color-bg);
}

.filter-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  max-width: 1100px;
  margin: 0 auto;
}

.filter-btn {
  padding: 0.5rem 1.25rem;
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 500;
  border: 1.5px solid #d1d5db;
  border-radius: 50px;
  background: var(--color-white);
  color: var(--color-text-mute);
  cursor: pointer;
  transition: all var(--transition);
}

.filter-btn:hover {
  border-color: var(--color-teal);
  color: var(--color-teal-dark);
}

.filter-btn.active {
  background: var(--color-teal);
  border-color: var(--color-teal);
  color: var(--color-bg-deep);
  font-weight: 700;
}

/* 記事一覧グリッド */
.all-articles {
  padding: 2rem 1.5rem 5rem;
  background: var(--color-bg);
}

.all-articles-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  max-width: 1100px;
  margin: 0 auto;
}

@media (min-width: 640px) {
  .all-articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 960px) {
  .all-articles-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* フィルタで非表示にするクラス */
.article-card.hidden {
  display: none;
}

/* ============================================================
   11. Aboutページ
   ============================================================ */

/* 想いセクション */
.about-story {
  padding: var(--section-padding);
  background: var(--color-white);
}

.about-story-inner {
  max-width: 740px;
  margin: 0 auto;
}

.story-quote {
  position: relative;
  padding: 2rem 0;
}

.story-quote::before {
  content: '\201C';
  font-family: Georgia, serif;
  font-size: 6rem;
  color: var(--color-teal);
  opacity: 0.15;
  position: absolute;
  top: -1.5rem;
  left: -0.5rem;
  line-height: 1;
}

.story-lead {
  font-size: clamp(1.125rem, 2.5vw, 1.3rem);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.9;
  margin-bottom: 2rem;
}

.story-body p {
  font-size: 1rem;
  line-height: 2;
  color: var(--color-text);
  margin-bottom: 1.5rem;
}

.story-body p:last-child {
  margin-bottom: 0;
}

.story-highlight {
  color: var(--color-teal-dark);
  font-weight: 700;
}

.story-emphasis {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  padding: 1.5rem;
  border-left: 4px solid var(--color-teal);
  margin: 2rem 0;
  background: rgba(0, 212, 212, 0.03);
  border-radius: 0 8px 8px 0;
}

/* 運営者情報 */
.about-profile {
  padding: var(--section-padding);
  background: var(--color-bg);
}

.profile-card {
  max-width: 740px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  text-align: center;
}

@media (min-width: 640px) {
  .profile-card {
    flex-direction: row;
    text-align: left;
  }
}

.profile-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-teal-dark) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.profile-avatar svg {
  width: 48px;
  height: 48px;
}

.profile-info h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  margin-bottom: 0.25rem;
}

.profile-role {
  font-size: 0.85rem;
  color: var(--color-teal-dark);
  font-weight: 500;
  margin-bottom: 1rem;
}

.profile-info p {
  font-size: 0.9rem;
  color: var(--color-text-mute);
  line-height: 1.8;
}

/* このサイトでできること */
.about-features {
  padding: var(--section-padding);
  background: var(--color-white);
}

.about-features-header {
  text-align: center;
  margin-bottom: 3rem;
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  max-width: 900px;
  margin: 0 auto;
}

@media (min-width: 640px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-item {
  text-align: center;
  padding: 2rem 1.5rem;
}

.feature-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-teal);
  color: var(--color-bg-deep);
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.feature-item h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.feature-item p {
  font-size: 0.85rem;
  color: var(--color-text-mute);
  line-height: 1.75;
}

/* CTA セクション */
.about-cta {
  padding: var(--section-padding);
  background: linear-gradient(135deg, var(--color-bg-deep) 0%, var(--color-navy) 100%);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.about-cta::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: radial-gradient(rgba(0, 212, 212, 0.06) 1px, transparent 1px);
  background-size: 30px 30px;
  pointer-events: none;
}

.about-cta .section-title {
  color: var(--color-white);
  position: relative;
  z-index: 1;
  margin-bottom: 2rem;
}

.about-cta .btn {
  position: relative;
  z-index: 1;
}

/* ============================================================
   12. 記事個別ページ（single.php）
   ============================================================ */
.single-article {
  padding: 8rem 1.5rem 5rem;
  background: var(--color-bg);
}

.single-article-inner {
  max-width: 800px;
  margin: 0 auto;
}

/* 記事ヘッダー */
.single-article-header {
  margin-bottom: 2rem;
}

.single-article-meta {
  display: flex;
  gap: 1rem;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.single-category-tag {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.75rem;
  border-radius: 50px;
  color: var(--color-white);
  background: var(--color-teal);
}

.single-date {
  font-size: 0.85rem;
  color: var(--color-text-mute);
}

.single-article-title {
  font-family: var(--font-heading);
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  font-weight: 700;
  line-height: 1.4;
  color: var(--color-text);
  margin-bottom: 1.5rem;
}

/* アイキャッチ画像 */
.single-thumbnail {
  width: 100%;
  border-radius: var(--card-radius);
  overflow: hidden;
  margin-bottom: 2.5rem;
  height: 320px;
}

.single-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.single-thumbnail-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.single-thumbnail-placeholder.basics-bg {
  background: linear-gradient(135deg, #0d1b2a 0%, #1a4a6a 100%);
}

.single-thumbnail-placeholder.symptom-bg {
  background: linear-gradient(135deg, #1a2e4a 0%, #00d4d4 100%);
}

.single-thumbnail-placeholder.case-bg {
  background: linear-gradient(135deg, #2d1b4e 0%, #ff6b6b 100%);
}

/* 本文スタイル */
.single-article-content {
  background: var(--color-white);
  border-radius: var(--card-radius);
  padding: 2.5rem;
  line-height: 2;
  overflow-x: hidden;
}

@media (max-width: 640px) {
  .single-article {
    padding: 6rem 1rem 3rem;
  }
  .single-article-content {
    padding: 1.25rem;
  }
  .single-article-content h2 {
    font-size: 1.2rem;
  }
}

.single-article-content h2 {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-teal);
}

.single-article-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 2rem 0 0.75rem;
  padding-left: 0.75rem;
  border-left: 4px solid var(--color-teal);
}

.single-article-content p {
  font-size: 1rem;
  color: var(--color-text);
  margin-bottom: 1.5rem;
}

.single-article-content ul,
.single-article-content ol {
  list-style: revert;
  padding-left: 1.5rem;
  margin-bottom: 1.5rem;
}

.single-article-content li {
  margin-bottom: 0.5rem;
}

.single-article-content blockquote {
  border-left: 4px solid var(--color-teal);
  padding: 1rem 1.5rem;
  background: rgba(0, 212, 212, 0.04);
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0;
  font-style: italic;
}

/* 前後記事ナビゲーション */
.post-navigation {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 3rem;
}

.nav-previous,
.nav-next {
  background: var(--color-white);
  border-radius: var(--card-radius);
  padding: 1.25rem;
  transition: all var(--transition);
}

.nav-previous:hover,
.nav-next:hover {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

.nav-next {
  text-align: right;
}

.nav-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-teal);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
}

.nav-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.5;
}

/* ============================================================
   13. サイドバー
   ============================================================ */
.sidebar {
  background: var(--color-white);
  border-radius: var(--card-radius);
  padding: 1.5rem;
}

.sidebar .widget {
  margin-bottom: 2rem;
}

.sidebar .widget:last-child {
  margin-bottom: 0;
}

.sidebar .widget-title {
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-teal);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid rgba(0, 212, 212, 0.2);
}

.sidebar ul li {
  padding: 0.4rem 0;
  border-bottom: 1px solid #f1f5f9;
}

.sidebar ul li:last-child {
  border-bottom: none;
}

.sidebar ul li a {
  font-size: 0.875rem;
  color: var(--color-text-mute);
  transition: color var(--transition);
}

.sidebar ul li a:hover {
  color: var(--color-teal-dark);
}

/* サイドバー検索フォーム */
.sidebar .search-form {
  display: flex;
  gap: 0.5rem;
}

.sidebar .search-field {
  flex: 1;
  padding: 0.5rem 0.75rem;
  border: 1.5px solid #e2e8f0;
  border-radius: 6px;
  font-family: var(--font-body);
  font-size: 0.85rem;
  outline: none;
  transition: border-color var(--transition);
}

.sidebar .search-field:focus {
  border-color: var(--color-teal);
}

.sidebar .search-submit {
  padding: 0.5rem 1rem;
  background: var(--color-teal);
  color: var(--color-bg-deep);
  border: none;
  border-radius: 6px;
  font-weight: 700;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background var(--transition);
}

.sidebar .search-submit:hover {
  background: var(--color-teal-dark);
}

/* ============================================================
   14. 404ページ
   ============================================================ */
.error-404 {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8rem 1.5rem 5rem;
  text-align: center;
}

.error-404-inner {
  max-width: 600px;
}

.error-404-number {
  font-family: var(--font-heading);
  font-size: clamp(6rem, 15vw, 10rem);
  font-weight: 700;
  color: var(--color-teal);
  opacity: 0.3;
  line-height: 1;
  margin-bottom: 1rem;
}

.error-404-title {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.error-404-message {
  color: var(--color-text-mute);
  margin-bottom: 2rem;
}

/* ============================================================
   15. 検索結果ページ
   ============================================================ */
.search-results-header {
  padding: 8rem 1.5rem 2rem;
  background: linear-gradient(135deg, var(--color-bg-deep) 0%, var(--color-navy) 100%);
  text-align: center;
}

.search-results-title {
  font-family: var(--font-heading);
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.5rem;
}

.search-results-count {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.6);
}

.search-results-grid {
  padding: 3rem 1.5rem 5rem;
  background: var(--color-bg);
}

.search-results-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 640px) {
  .search-results-inner {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 960px) {
  .search-results-inner {
    grid-template-columns: repeat(3, 1fr);
  }
}

.no-results {
  text-align: center;
  padding: 4rem 0;
  color: var(--color-text-mute);
}

/* ============================================================
   16. フッター
   ============================================================ */
.site-footer {
  background: var(--color-navy);
  padding: 3rem 1.5rem 2rem;
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  text-align: center;
}

.footer-logo {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.5rem;
}

.footer-logo .logo-accent {
  color: var(--color-teal);
}

.footer-tagline {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.4);
  margin-bottom: 1.5rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  margin-bottom: 2rem;
}

.footer-links a {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--color-teal);
}

.footer-copy {
  font-size: 0.75rem;
  color: rgba(255, 255, 255, 0.3);
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

/* ============================================================
   17. スクロールバー
   ============================================================ */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg);
}

::-webkit-scrollbar-thumb {
  background: #94a3b8;
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: #64748b;
}

/* ============================================================
   18. スキップリンク（アクセシビリティ）
   ============================================================ */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--color-teal);
  color: var(--color-bg-deep);
  padding: 0.75rem 1.5rem;
  font-weight: 700;
  z-index: 9999;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 0;
}