/* ============================================================
   DOOR Travel — Design System & Components
   Mobile-first responsive • Bilingual JP/EN
   ============================================================ */

/* --- Design Tokens --- */
:root {
  --indigo-900: #0c3040;
  --indigo-800: #185e72;
  --indigo-700: #2090af;
  --indigo-500: #57cae1;
  --indigo-300: #8ddcee;
  --indigo-200: #b5ecf5;
  --indigo-100: #dff6fb;

  --paper: #faf8f2;
  --surface: #ffffff;
  --ink: #1d2230;
  --ink-soft: #525a6e;
  --ink-faint: #8b91a3;

  --persimmon: #c1592b;
  --persimmon-deep: #a5481f;
  --persimmon-light: #d97a50;
  --persimmon-tint: #f6e7dc;

  --sage: #4f6f5e;
  --sage-tint: #e3ece6;

  --line: #e6e1d4;
  --line-soft: #efebe1;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --shadow-sm: 0 1px 2px rgba(12,48,64,.04), 0 4px 12px rgba(12,48,64,.05);
  --shadow-md: 0 2px 4px rgba(12,48,64,.04), 0 8px 24px rgba(12,48,64,.07);
  --shadow-lg: 0 4px 8px rgba(12,48,64,.05), 0 16px 40px rgba(12,48,64,.1);

  --font-display: "Shippori Mincho", serif;
  --font-ui: "Space Grotesk", sans-serif;
  --font-body: "Zen Kaku Gothic New", system-ui, sans-serif;
  --font-body-en: "Inter", system-ui, sans-serif;

  --header-h: 64px;
  --max-w: 1200px;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.8;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
[data-lang="en"] body { font-family: var(--font-body-en); }

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }
button { font: inherit; cursor: pointer; border: none; background: none; }

/* Utility */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 20px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }

/* ============================================================
   HEADER
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 248, 242, .88);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
  height: var(--header-h);
}
.header-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 20px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.logo-mark {
  width: 20px;
  height: 20px;
  background: url('../images/favicon.ico') center / contain no-repeat;
}
.logo-text {
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: .95rem;
  color: var(--indigo-800);
  letter-spacing: .02em;
}

/* Nav */
.nav-links {
  display: none;
  gap: 8px;
}
.nav-links a {
  font-family: var(--font-ui);
  font-size: .82rem;
  font-weight: 500;
  color: var(--ink-soft);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  transition: color .2s, background .2s;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--indigo-800);
  background: var(--indigo-100);
}

/* Language Toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
  flex-shrink: 0;
}
.lang-btn {
  font-family: var(--font-ui);
  font-size: .78rem;
  font-weight: 600;
  padding: 5px 12px;
  color: var(--ink-faint);
  transition: all .2s;
}
.lang-btn.active {
  background: var(--indigo-900);
  color: #fff;
}

/* Mobile menu */
.menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
}
.menu-toggle svg { width: 22px; height: 22px; color: var(--ink-soft); }
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-h);
  left: 0; right: 0;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  padding: 16px 20px;
  z-index: 99;
  box-shadow: var(--shadow-md);
}
.mobile-nav.open { display: block; }
.mobile-nav a {
  display: block;
  font-family: var(--font-ui);
  font-size: .9rem;
  font-weight: 500;
  color: var(--ink-soft);
  padding: 10px 0;
  border-bottom: 1px solid var(--line-soft);
}
.mobile-nav a:last-child { border-bottom: none; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  background: url('../images/hero-bg.png') center/cover no-repeat;
  color: #fff;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    160deg,
    rgba(12,48,64,.82) 0%,
    rgba(24,94,114,.70) 40%,
    rgba(32,144,175,.55) 100%
  );
  pointer-events: none;
}
.hero::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0; right: 0;
  height: 80px;
  background: linear-gradient(to top, var(--paper), transparent);
  pointer-events: none;
}
.hero-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 72px 20px 80px;
  position: relative;
  z-index: 2;
  text-align: center;
}
.hero-eyebrow {
  font-family: var(--font-ui);
  font-size: .72rem;
  letter-spacing: .35em;
  text-transform: uppercase;
  color: var(--indigo-200);
  margin-bottom: 20px;
}
.hero h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.6rem, 5vw, 2.8rem);
  line-height: 1.35;
  max-width: 720px;
  margin: 0 auto;
}
.hero h1 .accent { color: #f0c4a8; }
.hero-sub {
  font-size: clamp(.92rem, 1.5vw, 1.08rem);
  color: #cdd6ec;
  max-width: 560px;
  margin: 22px auto 0;
  line-height: 1.8;
}
.hero-stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 24px;
  margin-top: 36px;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,.12);
  font-family: var(--font-ui);
  font-size: .78rem;
  color: var(--indigo-200);
}
.hero-stats b { color: #fff; font-weight: 600; }

/* ============================================================
   CLUSTER SELECTION
   ============================================================ */
.section-heading {
  text-align: center;
  padding: 56px 0 32px;
}
.section-eyebrow {
  font-family: var(--font-ui);
  font-size: .7rem;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--persimmon);
  margin-bottom: 10px;
}
.section-heading h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.3rem, 3vw, 1.9rem);
  color: var(--indigo-900);
  line-height: 1.4;
}

.cluster-cards {
  display: grid;
  gap: 20px;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}
.cluster-card {
  background: linear-gradient(135deg, var(--indigo-900), var(--indigo-700));
  color: #fff;
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  cursor: pointer;
  transition: transform .25s, box-shadow .25s;
  position: relative;
  overflow: hidden;
}
.cluster-card::after {
  content: "";
  position: absolute;
  right: -40px;
  top: -40px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: rgba(193,89,43,.15);
  pointer-events: none;
}
.cluster-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}
.cluster-card.active {
  outline: 3px solid var(--persimmon);
  outline-offset: 2px;
}
.cluster-tag {
  display: inline-block;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: .72rem;
  letter-spacing: .1em;
  background: rgba(240,196,168,.18);
  color: #f0c4a8;
  padding: 5px 14px;
  border-radius: var(--radius-lg);
  margin-bottom: 12px;
}
.cluster-card h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.15rem;
  line-height: 1.4;
  margin-bottom: 6px;
}
.cluster-card p {
  font-size: .86rem;
  color: #cdd6ec;
  line-height: 1.6;
}
.cluster-count {
  font-family: var(--font-ui);
  font-size: .74rem;
  color: var(--indigo-200);
  margin-top: 10px;
}
.cluster-count b { color: #fff; }

/* ============================================================
   FILTER PILLS
   ============================================================ */
.filter-section {
  padding: 20px 0;
  text-align: center;
}
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}
.filter-pill {
  font-family: var(--font-ui);
  font-size: .8rem;
  font-weight: 500;
  padding: 7px 18px;
  border-radius: var(--radius-xl);
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink-soft);
  transition: all .2s;
}
.filter-pill:hover {
  border-color: var(--indigo-300);
  color: var(--indigo-700);
}
.filter-pill.active {
  background: var(--indigo-900);
  color: #fff;
  border-color: var(--indigo-900);
}
.filter-pill[data-filter="all"] { font-weight: 600; }

/* ============================================================
   ARTICLE CARDS GRID
   ============================================================ */
.cards-section {
  padding: 24px 0 56px;
}
.cards-grid {
  display: grid;
  gap: 20px;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 20px;
}
.card-count-label {
  text-align: center;
  font-family: var(--font-ui);
  font-size: .8rem;
  color: var(--ink-faint);
  margin-bottom: 20px;
}
.card-count-label b { color: var(--persimmon); font-weight: 600; }

/* Individual card */
.article-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  gap: 14px;
  transition: transform .2s, box-shadow .2s, opacity .3s;
  cursor: pointer;
}
.article-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--indigo-200);
}
.card-id {
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: .82rem;
  color: var(--persimmon);
  flex-shrink: 0;
  width: 36px;
  padding-top: 2px;
}
.card-body { min-width: 0; flex: 1; }
.card-title {
  font-weight: 700;
  font-size: .95rem;
  color: var(--indigo-900);
  line-height: 1.55;
  margin-bottom: 6px;
}
.card-aim {
  font-size: .83rem;
  color: var(--ink-soft);
  line-height: 1.6;
}
.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 10px;
}
.card-tag {
  font-family: var(--font-ui);
  font-size: .7rem;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  background: var(--sage-tint);
  color: var(--sage);
}
.card-cluster-tag {
  font-family: var(--font-ui);
  font-size: .7rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  background: var(--persimmon-tint);
  color: var(--persimmon-deep);
}
.article-card.hidden {
  display: none;
}
.article-card.fade-in {
  animation: cardFadeIn .35s ease both;
}
@keyframes cardFadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ============================================================
   ABOUT SECTION
   ============================================================ */
.about-section {
  background: var(--surface);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 64px 0;
}
.about-inner {
  max-width: 740px;
  margin: 0 auto;
  padding: 0 20px;
  text-align: center;
}
.about-inner h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.3rem, 3vw, 1.8rem);
  color: var(--indigo-900);
  margin-bottom: 24px;
  line-height: 1.4;
}
.about-inner p {
  font-size: 1rem;
  color: var(--ink-soft);
  line-height: 2;
  margin-bottom: 16px;
}
.about-features {
  display: grid;
  gap: 20px;
  margin-top: 36px;
  text-align: left;
}
.about-feature {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}
.about-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--persimmon-tint);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1.2rem;
}
.about-feature h3 {
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: .9rem;
  color: var(--indigo-900);
  margin-bottom: 2px;
}
.about-feature p {
  font-size: .86rem;
  color: var(--ink-soft);
  line-height: 1.7;
  margin: 0;
}

/* ============================================================
   FOOTER — DOOR style (dark, CareerIndex branding)
   ============================================================ */
.site-footer {
  background: #111827;
  color: rgba(255,255,255,.65);
  padding: 52px 0 0;
}
.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}
.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  margin-bottom: 8px;
}
.footer-logo .logo-mark { background: url('../images/favicon.ico') center / contain no-repeat; }
.footer-logo .logo-text { color: #fff; }
.footer-tagline {
  font-size: .82rem;
  color: rgba(255,255,255,.38);
  font-family: var(--font-ui);
}
.footer-mid {
  display: flex;
  gap: 48px;
  flex-wrap: wrap;
  margin: 36px 0 0;
  padding-bottom: 28px;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.footer-col h4 {
  font-family: var(--font-ui);
  font-size: .68rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: rgba(255,255,255,.32);
  margin-bottom: 12px;
}
.footer-col a {
  display: block;
  font-size: .84rem;
  color: rgba(255,255,255,.58);
  text-decoration: none;
  margin-bottom: 8px;
  transition: color .15s;
}
.footer-col a:hover { color: #fff; }
.footer-bottom {
  padding: 18px 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-legal {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}
.footer-legal a {
  font-size: .75rem;
  color: rgba(255,255,255,.38);
  text-decoration: none;
  font-family: var(--font-ui);
  transition: color .15s;
}
.footer-legal a:hover { color: rgba(255,255,255,.75); }
.footer-copy {
  font-size: .73rem;
  color: rgba(255,255,255,.28);
  font-family: var(--font-ui);
}

/* ============================================================
   ARTICLE DETAIL PAGE
   ============================================================ */
.article-hero {
  background: linear-gradient(160deg, var(--indigo-900) 0%, var(--indigo-800) 55%, var(--indigo-700) 100%);
  color: #fff;
  padding: 48px 0 56px;
  position: relative;
  overflow: hidden;
}
.article-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 80% 30%, rgba(193,89,43,.2), transparent 50%);
  pointer-events: none;
}
.article-hero-inner {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
  position: relative;
  z-index: 2;
}
.article-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-ui);
  font-size: .82rem;
  color: var(--indigo-200);
  margin-bottom: 24px;
  transition: color .2s;
}
.article-back:hover { color: #fff; }
.article-back svg { width: 16px; height: 16px; }
.article-id-badge {
  display: inline-block;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: .8rem;
  letter-spacing: .08em;
  background: rgba(240,196,168,.18);
  color: #f0c4a8;
  padding: 5px 16px;
  border-radius: var(--radius-lg);
  margin-bottom: 14px;
}
.article-hero h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.4rem, 4vw, 2.2rem);
  line-height: 1.4;
}
.article-hero .article-aim-text {
  font-size: 1rem;
  color: #cdd6ec;
  line-height: 1.8;
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid rgba(255,255,255,.12);
}

.article-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px 64px;
}

/* Affiliate Placeholder */
.affiliate-box {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 32px;
}
.affiliate-box h3 {
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: .9rem;
  color: var(--indigo-900);
  margin-bottom: 12px;
}
.affiliate-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.affiliate-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-ui);
  font-size: .84rem;
  font-weight: 500;
  padding: 8px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  color: var(--indigo-700);
  transition: all .2s;
}
.affiliate-link:hover {
  border-color: var(--persimmon);
  color: var(--persimmon);
  background: var(--persimmon-tint);
}
.affiliate-link svg { width: 14px; height: 14px; }

/* Related articles */
.related-section {
  margin-top: 8px;
}
.related-section h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--indigo-900);
  margin-bottom: 16px;
}
.related-grid {
  display: grid;
  gap: 12px;
}
.related-card {
  display: flex;
  gap: 12px;
  padding: 14px 16px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  transition: border-color .2s, box-shadow .2s;
}
.related-card:hover {
  border-color: var(--indigo-200);
  box-shadow: var(--shadow-sm);
}
.related-card .card-id {
  font-size: .78rem;
  width: 32px;
}
.related-card .card-title {
  font-size: .88rem;
}

/* ============================================================
   RESPONSIVE — Tablet (768px+)
   ============================================================ */
@media (min-width: 768px) {
  .container { padding: 0 32px; }
  .header-inner { padding: 0 32px; }

  .nav-links { display: flex; }
  .menu-toggle { display: none; }

  .hero-inner { padding: 88px 32px 96px; }

  .cluster-cards { grid-template-columns: 1fr 1fr; }

  .cards-grid { grid-template-columns: 1fr 1fr; }

  .about-features { grid-template-columns: 1fr 1fr; }

  .related-grid { grid-template-columns: 1fr 1fr; }

  .footer-inner { padding: 0 32px; }
}

/* ============================================================
   RESPONSIVE — Desktop (1024px+)
   ============================================================ */
@media (min-width: 1024px) {
  .cards-grid { grid-template-columns: 1fr 1fr 1fr; }
}

/* ============================================================
   SCROLL-BASED NAV HIGHLIGHT
   ============================================================ */
.nav-links a.scrolled-active {
  color: var(--persimmon);
}

/* ============================================================
   BACK TO TOP
   ============================================================ */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--indigo-900);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity .3s, visibility .3s, transform .2s;
  z-index: 50;
  box-shadow: var(--shadow-md);
}
.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}
.back-to-top:hover {
  transform: translateY(-2px);
  background: var(--indigo-700);
}
.back-to-top svg { width: 20px; height: 20px; }

/* ============================================================
   NO RESULTS
   ============================================================ */
.no-results {
  text-align: center;
  padding: 48px 20px;
  color: var(--ink-faint);
  font-size: .92rem;
  display: none;
}
.no-results.show { display: block; }