/* ============================================
   Vietnam Japan Guide - Redesigned UI
   デザインコンセプト: Trust / Sophisticated / Intuitive
   メインカラー: ディープネイビー #1A365D
   アクセントカラー: カッパーゴールド #C5A059
   ============================================ */

/* ---------- CSS Custom Properties ---------- */
:root {
  --color-primary: #1A365D;
  --color-primary-light: #2C5282;
  --color-primary-dark: #0F2440;
  --color-accent: #C5A059;
  --color-accent-light: #D4B87A;
  --color-accent-dark: #A8823E;
  --color-white: #FFFFFF;
  --color-bg: #FFFFFF;
  --color-bg-gray: #F7FAFC;
  --color-bg-dark: #1A202C;
  --color-border: #E2E8F0;
  --color-text: #1A202C;
  --color-text-secondary: #718096;
  --color-text-muted: #A0AEC0;
  --color-text-inverse: #FFFFFF;
  --font-sans: 'Noto Sans JP', 'Noto Sans', 'Hiragino Sans', 'Helvetica Neue', Arial, sans-serif;
  --fs-xs: 0.75rem;
  --fs-sm: 0.875rem;
  --fs-base: 0.9375rem;
  --fs-md: 1rem;
  --fs-lg: 1.25rem;
  --fs-xl: 1.5rem;
  --fs-2xl: 2rem;
  --fs-3xl: 2.5rem;
  --fs-4xl: 3rem;
  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 0.75rem;
  --sp-4: 1rem;
  --sp-5: 1.25rem;
  --sp-6: 1.5rem;
  --sp-8: 2rem;
  --sp-10: 2.5rem;
  --sp-12: 3rem;
  --sp-16: 4rem;
  --sp-20: 5rem;
  --container: 1200px;
  --container-narrow: 720px;
  --header-h: 64px;
  --radius: 8px;
  --radius-sm: 4px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.12);
  --transition: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 150ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1A202C;
    --color-bg-gray: #2D3748;
    --color-border: #4A5568;
    --color-text: #E2E8F0;
    --color-text-secondary: #A0AEC0;
    --color-text-muted: #718096;
    --color-primary: #2C5282;
    --color-primary-light: #3182CE;
  }
  body { background: var(--color-bg); }
  .header { background: var(--color-bg); }
  .category-card { background: var(--color-bg-gray); }
  .article-content .info-box { background: var(--color-bg-gray); }
  .footer { background: var(--color-primary-dark); }
  .hero__overlay { background: linear-gradient(135deg, rgba(26,54,93,0.95) 0%, rgba(15,36,64,0.9) 100%); }
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  transition: background var(--transition), color var(--transition);
}
a { color: var(--color-primary-light); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-accent); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
::selection { background: var(--color-accent); color: var(--color-white); }
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 var(--sp-6); }
.container-narrow { max-width: var(--container-narrow); }
h1, h2, h3, h4 { font-weight: 700; line-height: 1.3; color: var(--color-text); }
h1 { font-size: var(--fs-3xl); margin-bottom: var(--sp-6); letter-spacing: -0.02em; }
h2 { font-size: var(--fs-2xl); margin-bottom: var(--sp-4); letter-spacing: -0.01em; }
h3 { font-size: var(--fs-xl); margin-bottom: var(--sp-3); }
h4 { font-size: var(--fs-lg); margin-bottom: var(--sp-2); }
p { margin-bottom: var(--sp-4); }
.text-sm { font-size: var(--fs-sm); }
.text-xs { font-size: var(--fs-xs); }
.text-secondary { color: var(--color-text-secondary); }
.text-center { text-align: center; }
.text-accent { color: var(--color-accent); }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: var(--sp-2);
  font-family: var(--font-sans); font-weight: 600; font-size: var(--fs-sm);
  padding: var(--sp-3) var(--sp-6); border-radius: var(--radius); border: none;
  cursor: pointer; transition: all var(--transition); text-decoration: none;
}
.btn-primary { background: var(--color-primary); color: var(--color-white); }
.btn-primary:hover { background: var(--color-primary-light); transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-accent { background: var(--color-accent); color: var(--color-white); }
.btn-accent:hover { background: var(--color-accent-light); transform: translateY(-1px); box-shadow: var(--shadow-md); color: var(--color-white); }
.btn-secondary { background: transparent; color: var(--color-primary); border: 2px solid var(--color-primary); }
.btn-secondary:hover { background: var(--color-primary); color: var(--color-white); transform: translateY(-1px); }
.btn-lg { padding: var(--sp-4) var(--sp-8); font-size: var(--fs-md); }
.btn-block { width: 100%; }
.btn-ghost { background: transparent; color: var(--color-text-inverse); border: 2px solid rgba(255,255,255,0.3); }
.btn-ghost:hover { border-color: var(--color-accent); color: var(--color-accent); }

.header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.98); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border); height: var(--header-h); transition: background var(--transition);
}
.header__inner { display: flex; align-items: center; justify-content: space-between; height: 100%; max-width: var(--container); margin: 0 auto; padding: 0 var(--sp-6); }
.header__logo { display: flex; align-items: center; gap: var(--sp-2); font-size: var(--fs-lg); font-weight: 700; color: var(--color-primary); }
.header__logo:hover { color: var(--color-accent); }
.header__logo-icon { width: 34px; height: 34px; background: var(--color-primary); border-radius: 6px; display: flex; align-items: center; justify-content: center; color: var(--color-white); font-weight: 900; font-size: var(--fs-sm); }
.header__logo:hover .header__logo-icon { background: var(--color-accent); }
.header__nav-list { display: flex; gap: var(--sp-1); }
.header__nav-link { font-size: var(--fs-sm); font-weight: 500; color: var(--color-text-secondary); padding: var(--sp-2) var(--sp-3); border-radius: var(--radius); transition: all var(--transition); position: relative; }
.header__nav-link::after { content: ''; position: absolute; bottom: 2px; left: var(--sp-3); right: var(--sp-3); height: 2px; background: var(--color-accent); transform: scaleX(0); transition: transform var(--transition); }
.header__nav-link:hover { color: var(--color-primary); background: rgba(197,160,89,0.08); }
.header__nav-link:hover::after { transform: scaleX(1); }
.header__nav-link--active { color: var(--color-primary); }
.header__nav-link--active::after { transform: scaleX(1); }
.header__cta { display: inline-flex; align-items: center; gap: var(--sp-2); background: var(--color-accent); color: var(--color-white); font-size: var(--fs-sm); font-weight: 600; padding: var(--sp-2) var(--sp-4); border-radius: var(--radius); transition: all var(--transition); }
.header__cta:hover { background: var(--color-accent-light); transform: translateY(-1px); box-shadow: var(--shadow-md); color: var(--color-white); }
.header__search-btn { background: none; border: none; font-size: var(--fs-lg); cursor: pointer; padding: var(--sp-2); border-radius: var(--radius); color: var(--color-text-secondary); }
.header__search-btn:hover { background: var(--color-bg-gray); color: var(--color-primary); }
.header__menu-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: var(--sp-2); background: none; border: none; }
.header__menu-toggle span { display: block; width: 22px; height: 2px; background: var(--color-text); border-radius: 2px; transition: all var(--transition); }
.header__menu-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.header__menu-toggle.active span:nth-child(2) { opacity: 0; }
.header__menu-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.hero { position: relative; background: var(--color-primary); padding: var(--sp-20) 0 var(--sp-16); text-align: center; overflow: hidden; }
.hero__background { position: absolute; top: 0; left: 0; right: 0; bottom: 0; background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="rgba(255,255,255,0.03)" d="M0,160L48,176C96,192,192,224,288,213.3C384,203,480,149,576,138.7C672,128,768,160,864,181.3C960,203,1056,213,1152,197.3C1248,181,1344,139,1392,117.3L1440,96L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>'); background-size: cover; background-position: center bottom; opacity: 0.4; }
@media (prefers-color-scheme: dark) { .hero__background { opacity: 0.15; } }
.hero__overlay { position: absolute; top: 0; left: 0; right: 0; bottom: 0; background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%); }
.hero__content { position: relative; z-index: 2; max-width: 720px; margin: 0 auto; }
.hero__title { color: var(--color-white); font-size: var(--fs-4xl); font-weight: 800; line-height: 1.2; margin-bottom: var(--sp-4); letter-spacing: -0.02em; }
.hero__subtitle { color: rgba(255,255,255,0.85); font-size: var(--fs-lg); line-height: 1.6; margin-bottom: var(--sp-8); max-width: 600px; margin-left: auto; margin-right: auto; }
.hero__search { position: relative; max-width: 560px; margin: 0 auto; }
.hero__search-icon { position: absolute; left: var(--sp-4); top: 50%; transform: translateY(-50%); font-size: var(--fs-lg); z-index: 3; }
.hero__search-input { width: 100%; padding: var(--sp-4) var(--sp-4) var(--sp-4) var(--sp-12); border: none; border-radius: var(--radius-lg); font-size: var(--fs-md); font-family: var(--font-sans); background: var(--color-white); box-shadow: var(--shadow-lg); }
.hero__search-input:focus { outline: none; box-shadow: 0 0 0 3px var(--color-accent), var(--shadow-lg); }
.hero__actions { display: flex; gap: var(--sp-4); justify-content: center; margin-top: var(--sp-8); }

.quick-access { padding: var(--sp-8) 0; background: var(--color-white); border-bottom: 1px solid var(--color-border); }
.quick-access__list { display: flex; gap: var(--sp-4); justify-content: center; flex-wrap: wrap; }
.quick-access__item { display: flex; flex-direction: column; align-items: center; gap: var(--sp-2); padding: var(--sp-4) var(--sp-6); border-radius: var(--radius-lg); background: var(--color-bg-gray); transition: all var(--transition); cursor: pointer; min-width: 100px; }
.quick-access__item:hover { background: var(--color-primary); color: var(--color-white); transform: translateY(-2px); box-shadow: var(--shadow-md); }
.quick-access__item:hover .quick-access__label { color: var(--color-white); }
.quick-access__item:hover .quick-access__icon { transform: scale(1.1); }
.quick-access__icon { font-size: 1.75rem; transition: transform var(--transition); }
.quick-access__label { font-size: var(--fs-xs); font-weight: 600; color: var(--color-text-secondary); text-align: center; }

.section { padding: var(--sp-16) 0; }
.section--gray { background: var(--color-bg-gray); }
.section__title { text-align: center; margin-bottom: var(--sp-10); }
.section__title h2 { position: relative; display: inline-block; }
.section__title h2::after { content: ''; display: block; width: 60px; height: 3px; background: var(--color-accent); margin: var(--sp-3) auto 0; border-radius: 2px; }
.section__title p { color: var(--color-text-secondary); margin-top: var(--sp-2); }

.categories-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--sp-6); align-items: stretch; }
.category-card { background: var(--color-white); border-radius: var(--radius-lg); border: 1px solid var(--color-border); overflow: hidden; transition: all var(--transition); display: flex; flex-direction: column; min-height: 380px; }
.category-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--color-accent); }
.category-card__header { padding: var(--sp-5) var(--sp-5); text-align: center; border-bottom: 1px solid var(--color-border); }
.category-card__icon { font-size: 2rem; margin-bottom: var(--sp-2); }
.category-card__title { font-size: var(--fs-md); font-weight: 700; margin-bottom: var(--sp-1); color: var(--color-primary); }
.category-card__subtitle { font-size: var(--fs-xs); color: var(--color-text-secondary); }
.category-card__body { padding: var(--sp-4) var(--sp-5); flex: 1; display: flex; flex-direction: column; }
.category-card__description { font-size: var(--fs-sm); color: var(--color-text-secondary); line-height: 1.6; margin-bottom: var(--sp-3); flex: 1; }
.category-card__stats { display: flex; gap: var(--sp-2); flex-wrap: wrap; margin-top: auto; }
.category-card__stats span { font-size: var(--fs-xs); padding: var(--sp-1) var(--sp-2); background: rgba(197,160,89,0.1); border-radius: var(--radius-sm); color: var(--color-accent-dark); font-weight: 500; }
.category-card__footer { padding: var(--sp-3) var(--sp-5); border-top: 1px solid var(--color-border); margin-top: auto; min-height: 48px; display: flex; align-items: center; }

.articles-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: var(--sp-6); }
.article-card { background: var(--color-white); border-radius: var(--radius-lg); border: 1px solid var(--color-border); overflow: hidden; transition: all var(--transition); }
.article-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.article-card__image { height: 160px; display: flex; align-items: center; justify-content: center; font-size: 3rem; background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%); color: rgba(255,255,255,0.3); position: relative; }
.article-card__category { position: absolute; top: var(--sp-3); left: var(--sp-3); font-size: var(--fs-xs); font-weight: 600; padding: var(--sp-1) var(--sp-3); background: var(--color-accent); color: var(--color-white); border-radius: var(--radius-sm); }
.article-card__content { padding: var(--sp-5); }

.article-card__title { font-size: var(--fs-md); font-weight: 700; margin-bottom: var(--sp-2); line-height: 1.4; }
.article-card__title a { color: var(--color-text); }
.article-card__title a:hover { color: var(--color-primary-light); }
.article-card__excerpt { font-size: var(--fs-sm); color: var(--color-text-secondary); line-height: 1.6; margin-bottom: var(--sp-3); }
.article-card__meta { display: flex; gap: var(--sp-3); font-size: var(--fs-xs); color: var(--color-text-muted); }

.layout-two-col { display: grid; grid-template-columns: 1fr 300px; gap: var(--sp-8); align-items: start; }
@media (max-width: 900px) { .layout-two-col { grid-template-columns: 1fr; } .layout-two-col > .sidebar { order: -1; } }

.sidebar { position: sticky; top: calc(var(--header-h) + var(--sp-6)); }
.sidebar__widget { background: var(--color-white); border-radius: var(--radius-lg); border: 1px solid var(--color-border); padding: var(--sp-6); margin-bottom: var(--sp-6); }
.sidebar__widget-title { font-size: var(--fs-md); font-weight: 700; margin-bottom: var(--sp-4); padding-bottom: var(--sp-3); border-bottom: 2px solid var(--color-accent); color: var(--color-primary); }

.ranking-list { counter-reset: rank; }
.ranking-item { display: flex; gap: var(--sp-3); padding: var(--sp-3) 0; border-bottom: 1px solid var(--color-border); transition: all var(--transition); cursor: pointer; }
.ranking-item:last-child { border-bottom: none; }
.ranking-item:hover { padding-left: var(--sp-2); }
.ranking-item__num { width: 24px; height: 24px; background: var(--color-bg-gray); border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center; font-size: var(--fs-xs); font-weight: 700; color: var(--color-text-secondary); flex-shrink: 0; }
.ranking-item:nth-child(1) .ranking-item__num { background: var(--color-accent); color: var(--color-white); }
.ranking-item:nth-child(2) .ranking-item__num { background: var(--color-accent-light); color: var(--color-white); }
.ranking-item:nth-child(3) .ranking-item__num { background: #E2D4B8; color: var(--color-primary); }
.ranking-item__title { font-size: var(--fs-sm); font-weight: 500; line-height: 1.4; color: var(--color-text); }
.ranking-item:hover .ranking-item__title { color: var(--color-primary-light); }

.sidebar-cta { background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%); padding: var(--sp-6); border-radius: var(--radius-lg); text-align: center; color: var(--color-white); }
.sidebar-cta__icon { font-size: 2.5rem; margin-bottom: var(--sp-3); }
.sidebar-cta__title { font-size: var(--fs-lg); font-weight: 700; margin-bottom: var(--sp-2); }
.sidebar-cta__text { font-size: var(--fs-sm); opacity: 0.9; margin-bottom: var(--sp-4); line-height: 1.6; }

.footer { background: var(--color-primary-dark); color: rgba(255,255,255,0.8); padding: var(--sp-12) 0 var(--sp-8); margin-top: var(--sp-12); }
.footer__grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: var(--sp-8); max-width: var(--container); margin: 0 auto; padding: 0 var(--sp-6); }
.footer__section-title { color: var(--color-accent); font-size: var(--fs-sm); font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: var(--sp-4); }
.footer__links { list-style: none; padding: 0; }
.footer__links li { margin-bottom: var(--sp-2); }
.footer__links a { color: rgba(255,255,255,0.7); font-size: var(--fs-sm); transition: all var(--transition); }
.footer__links a:hover { color: var(--color-accent); padding-left: 2px; }
.footer__bottom { text-align: center; padding-top: var(--sp-8); margin-top: var(--sp-8); border-top: 1px solid rgba(255,255,255,0.1); font-size: var(--fs-xs); color: rgba(255,255,255,0.5); max-width: var(--container); margin-left: auto; margin-right: auto; padding-left: var(--sp-6); padding-right: var(--sp-6); }

.back-to-top { position: fixed; bottom: var(--sp-6); right: var(--sp-6); width: 44px; height: 44px; border-radius: 50%; background: var(--color-primary); color: var(--color-white); border: none; font-size: var(--fs-xl); cursor: pointer; box-shadow: var(--shadow-md); transition: all var(--transition); opacity: 0; visibility: hidden; z-index: 50; display: flex; align-items: center; justify-content: center; }
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { background: var(--color-accent); transform: translateY(-2px); box-shadow: var(--shadow-lg); }

@keyframes fadeInUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
.animate-fade-in { animation: fadeInUp 0.6s ease forwards; }
.animate-fade-in-delay-1 { animation-delay: 0.1s; }
.animate-fade-in-delay-2 { animation-delay: 0.2s; }
.animate-fade-in-delay-3 { animation-delay: 0.3s; }

@media (max-width: 768px) {
  :root { --fs-3xl: 1.75rem; --fs-4xl: 2rem; --header-h: 56px; }
  .header__nav { display: none; }
  .header__nav.open { display: block; position: absolute; top: var(--header-h); left: 0; right: 0; background: var(--color-white); border-bottom: 1px solid var(--color-border); padding: var(--sp-4); box-shadow: var(--shadow-md); }
  .header__nav.open .header__nav-list { flex-direction: column; }
  .header__menu-toggle { display: flex; }
  .header__cta { display: none; }
  .hero { padding: var(--sp-12) 0 var(--sp-10); }
  .hero__title { font-size: var(--fs-3xl); }
  .hero__subtitle { font-size: var(--fs-md); }
  .hero__actions { flex-direction: column; align-items: stretch; }
  .quick-access__list { gap: var(--sp-2); }
  .quick-access__item { padding: var(--sp-3); min-width: 80px; }
  .quick-access__icon { font-size: 1.25rem; }
  .categories-grid { grid-template-columns: 1fr; }
  .articles-grid { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
  .section { padding: var(--sp-10) 0; }
  .hero { padding: var(--sp-8) 0; }
  .footer__grid { grid-template-columns: 1fr; }
}

@media print {
  .header, .footer, .back-to-top, .sidebar { display: none; }
}