/* ===========================================================
   2007年三田会 公式サイト スタイルシート
   =========================================================== */

:root {
  --keio-blue: #002664;
  --keio-blue-deep: #000033;
  --keio-red: #8a1538;
  --keio-red-deep: #6e0f2b;
  --paper: #ffffff;
  --paper-soft: #f7f6f3;
  --paper-line: #e4e1d8;
  --ink: #1c1c1e;
  --ink-soft: #55575f;
  --gold: #b79b5b;

  --font-serif: 'Noto Serif JP', serif;
  --font-sans: 'Noto Sans JP', sans-serif;

  --header-h: 76px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-h);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.9;
  -webkit-font-smoothing: antialiased;
}

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

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

ul { margin: 0; padding: 0; list-style: none; }

.sp-only { display: none; }

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 28px;
}

.container-narrow {
  max-width: 820px;
  margin: 0 auto;
}

/* ---------- Section base ---------- */
.section {
  padding: 96px 0;
}

.section-title {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 6px;
  margin-bottom: 52px;
}

.section-title .ja {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 2rem;
  color: var(--keio-blue-deep);
  letter-spacing: 0.06em;
  position: relative;
  padding-bottom: 20px;
}

.section-title .ja::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 56px;
  height: 3px;
  background: linear-gradient(90deg, var(--keio-blue) 0 30%, var(--keio-red) 70% 100%);
}

.section-title .en {
  font-size: 0.72rem;
  letter-spacing: 0.32em;
  color: var(--gold);
  font-weight: 600;
  text-transform: uppercase;
}

.section-title-invert .ja { color: var(--paper); }

.subsection-title {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  color: var(--keio-blue-deep);
  margin: 48px 0 24px;
  padding-left: 16px;
  border-left: 4px solid var(--keio-red);
}

.lead {
  font-size: 1.08rem;
  font-weight: 500;
  color: var(--ink);
}

.callout {
  background: var(--paper-soft);
  border-left: 4px solid var(--keio-blue);
  padding: 22px 26px;
  margin-top: 28px;
  font-size: 0.98rem;
  color: var(--ink-soft);
}

.center-cta {
  text-align: center;
  margin-top: 44px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 15px 36px;
  border-radius: 2px;
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  border: 1px solid transparent;
  transition: all 0.25s ease;
}

.btn-primary {
  background: var(--keio-red);
  color: #fff;
  border-color: var(--keio-red);
}
.btn-primary:hover { background: var(--keio-red-deep); border-color: var(--keio-red-deep); }

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.7);
}
.btn-outline:hover { background: rgba(255,255,255,0.12); }

.btn-outline-dark {
  background: transparent;
  color: var(--keio-blue-deep);
  border-color: var(--keio-blue-deep);
}
.btn-outline-dark:hover { background: var(--keio-blue-deep); color: #fff; }

.btn-invert {
  background: var(--gold);
  color: var(--keio-blue-deep);
  border-color: var(--gold);
}
.btn-invert:hover { background: #cbb479; }

.btn-disabled {
  background: rgba(255,255,255,0.12);
  color: rgba(255,255,255,0.6);
  border-color: rgba(255,255,255,0.25);
  cursor: default;
}
.btn-disabled:hover { background: rgba(255,255,255,0.12); }

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  z-index: 1000;
  background: rgba(255,255,255,0.94);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--paper-line);
  transition: box-shadow 0.3s ease;
}
.site-header.scrolled { box-shadow: 0 4px 18px rgba(0,0,51,0.08); }

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  height: 100%;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-emblem {
  width: 44px;
  height: 44px;
  object-fit: contain;
  flex-shrink: 0;
}

.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-main { font-family: var(--font-serif); font-weight: 700; font-size: 1.08rem; color: var(--keio-blue-deep); }
.brand-sub { font-size: 0.6rem; letter-spacing: 0.06em; color: var(--ink-soft); }

.site-nav ul {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--ink);
  position: relative;
  padding: 8px 0;
  white-space: nowrap;
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--keio-red);
  transition: width 0.25s ease;
}
.nav-link:hover::after { width: 100%; }

.nav-link.active {
  color: var(--keio-red);
  font-weight: 700;
}
.nav-link.active::after { width: 100%; }

.nav-cta {
  background: var(--keio-blue-deep);
  color: #fff !important;
  padding: 9px 20px;
  border-radius: 2px;
  font-weight: 700;
}
.nav-cta::after { display: none; }
.nav-cta:hover { background: var(--keio-red); }
.nav-cta.active { background: var(--keio-red); }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--keio-blue-deep);
  transition: all 0.3s ease;
}
.nav-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #fff;
  background:
    linear-gradient(160deg, rgba(0,0,51,0.88) 0%, rgba(0,38,100,0.82) 55%, rgba(138,21,56,0.72) 100%),
    repeating-linear-gradient(135deg, rgba(255,255,255,0.03) 0 2px, transparent 2px 40px);
  overflow: hidden;
  padding-top: var(--header-h);
}

.hero-tricolor {
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 6px;
  background: linear-gradient(90deg, var(--keio-blue-deep) 0 33.3%, var(--gold) 33.3% 66.6%, var(--keio-red) 66.6% 100%);
}

.hero-inner { position: relative; z-index: 2; padding: 0 24px; }

.hero-eyebrow {
  font-size: 0.78rem;
  letter-spacing: 0.34em;
  color: var(--gold);
  font-weight: 600;
  margin-bottom: 26px;
}

.hero-copy {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(2.1rem, 5vw, 3.6rem);
  line-height: 1.5;
  margin: 0 0 22px;
  letter-spacing: 0.03em;
}

.hero-sub {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  letter-spacing: 0.2em;
  color: rgba(255,255,255,0.85);
  margin: 0 0 48px;
}

.hero-actions {
  display: flex;
  gap: 18px;
  justify-content: center;
  flex-wrap: wrap;
}

.scroll-cue {
  position: absolute;
  bottom: 34px;
  left: 50%;
  transform: translateX(-50%);
  width: 26px;
  height: 44px;
  border: 2px solid rgba(255,255,255,0.55);
  border-radius: 20px;
  z-index: 2;
}
.scroll-cue span {
  position: absolute;
  top: 8px;
  left: 50%;
  width: 4px;
  height: 4px;
  margin-left: -2px;
  border-radius: 50%;
  background: #fff;
  animation: scrollDown 1.6s infinite;
}
@keyframes scrollDown {
  0% { opacity: 1; top: 8px; }
  70% { opacity: 0; top: 24px; }
  100% { opacity: 0; top: 24px; }
}

/* ---------- Page Hero (sub-pages) ---------- */
.page-hero {
  position: relative;
  text-align: center;
  color: #fff;
  padding: calc(var(--header-h) + 72px) 24px 68px;
  background:
    linear-gradient(160deg, rgba(0,0,51,0.94) 0%, rgba(0,38,100,0.88) 55%, rgba(138,21,56,0.78) 100%),
    repeating-linear-gradient(135deg, rgba(255,255,255,0.03) 0 2px, transparent 2px 40px);
  overflow: hidden;
}

.page-hero-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(1.7rem, 4vw, 2.5rem);
  letter-spacing: 0.06em;
  margin: 0 0 16px;
}

.page-hero-lead {
  font-size: 0.98rem;
  color: rgba(255,255,255,0.85);
  margin: 0;
  max-width: 560px;
  margin: 0 auto;
}

/* ---------- News ---------- */
.section-news { background: var(--paper-soft); padding: 64px 0; }

.news-list {
  border-top: 1px solid var(--paper-line);
}

.news-item {
  display: flex;
  align-items: baseline;
  gap: 20px;
  padding: 20px 8px;
  border-bottom: 1px solid var(--paper-line);
  flex-wrap: wrap;
}

.news-date {
  font-family: var(--font-serif);
  color: var(--keio-blue);
  font-weight: 600;
  font-size: 0.92rem;
  min-width: 100px;
}

.news-tag {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--keio-red);
  border: 1px solid var(--keio-red);
  padding: 3px 10px;
  border-radius: 12px;
  white-space: nowrap;
}

.news-text {
  flex: 1;
  min-width: 240px;
  font-size: 0.95rem;
  color: var(--ink);
}

.news-link {
  color: var(--keio-blue);
  font-weight: 700;
  border-bottom: 1px solid var(--keio-blue);
}

/* ---------- Greeting ---------- */
.section-greeting { background: var(--paper); }
.greeting-body p { margin: 0 0 24px; color: var(--ink-soft); }
.greeting-body p:last-child { margin-bottom: 0; }
.greeting-body strong { color: var(--keio-red); font-weight: 700; }

/* ---------- About ---------- */
.section-about { background: var(--paper-soft); }
.section-about p { color: var(--ink-soft); }

.check-list {
  margin: 24px 0 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.check-list li {
  position: relative;
  padding: 16px 22px 16px 52px;
  background: var(--paper);
  border: 1px solid var(--paper-line);
  border-radius: 4px;
  font-size: 0.95rem;
  color: var(--ink);
}
.check-list li::before {
  content: "✓";
  position: absolute;
  left: 20px;
  top: 15px;
  color: var(--paper);
  background: var(--keio-blue);
  width: 22px;
  height: 22px;
  border-radius: 50%;
  font-size: 0.72rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ---------- Rengo ---------- */
.section-rengo { background: var(--paper); }
.section-rengo p { color: var(--ink-soft); }
.section-rengo .subsection-title { text-align: left; max-width: 1120px; margin-left: auto; margin-right: auto; }

.bukai-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.bukai-card {
  background: var(--paper-soft);
  border-top: 3px solid var(--keio-blue);
  padding: 26px 24px;
  border-radius: 2px;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.bukai-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px rgba(0,0,51,0.1);
  border-top-color: var(--keio-red);
}

.bukai-no {
  font-family: var(--font-serif);
  font-size: 0.85rem;
  color: var(--gold);
  font-weight: 700;
  letter-spacing: 0.1em;
}

.bukai-card h4 {
  font-family: var(--font-serif);
  font-size: 1.08rem;
  color: var(--keio-blue-deep);
  margin: 8px 0 12px;
}

.bukai-card p {
  font-size: 0.88rem;
  margin: 0;
  color: var(--ink-soft);
}

.bukai-card-lead {
  border-top-color: var(--keio-red);
  background: #fdf4f6;
}

.bukai-sub {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--ink-soft);
}

/* ---------- Departments page ---------- */
.section-departments-intro { padding: 80px 0 24px; }
.section-departments-intro .lead { text-align: center; }
.section-departments-intro .callout { text-align: center; }
.section-departments-intro .callout a { color: var(--keio-blue); font-weight: 700; border-bottom: 1px solid var(--keio-blue); }
.section-departments { padding-top: 24px; }

/* ---------- Board page ---------- */
.section-board { padding: 80px 0; }
.section-board-alt { background: var(--paper-soft); }

.board-lead {
  text-align: center;
  color: var(--ink-soft);
  margin: -24px 0 32px;
}

.board-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 14px;
}

.board-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: var(--paper);
  border: 1px solid var(--paper-line);
  border-left: 3px solid var(--keio-blue);
  padding: 16px 20px;
  border-radius: 2px;
}

.board-item-lead {
  border-left-color: var(--keio-red);
  background: #fdf4f6;
}

.board-role {
  font-size: 0.82rem;
  color: var(--ink-soft);
}

.board-name {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1rem;
  color: var(--keio-blue-deep);
  text-align: right;
}

.section-board .callout { text-align: center; margin-top: 40px; }
.section-board .callout a { color: var(--keio-blue); font-weight: 700; border-bottom: 1px solid var(--keio-blue); }

/* ---------- Privacy Policy ---------- */
.privacy-body .subsection-title {
  text-align: left;
  margin-top: 44px;
}
.privacy-body .subsection-title:first-of-type { margin-top: 0; }

.policy-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 18px 0;
}
.policy-list li {
  position: relative;
  padding-left: 20px;
  font-size: 0.95rem;
  color: var(--ink-soft);
}
.policy-list li::before {
  content: "・";
  position: absolute;
  left: 0;
  color: var(--keio-red);
}

.privacy-org {
  margin-top: 20px;
  color: var(--ink);
  line-height: 1.9;
}

.privacy-date {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--paper-line);
  color: var(--ink-soft);
  font-size: 0.88rem;
  text-align: right;
}

/* ---------- Recruit ---------- */
.section-recruit { background: var(--paper-soft); }
.section-recruit p { color: var(--ink-soft); }

.voice-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 22px 0 0;
}
.voice-list li {
  position: relative;
  padding: 14px 20px 14px 20px;
  background: var(--paper);
  border-left: 3px solid var(--keio-red);
  font-size: 0.95rem;
  color: var(--ink);
}

.task-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 26px;
}

.task-card {
  background: var(--paper);
  border: 1px solid var(--paper-line);
  border-radius: 4px;
  padding: 24px;
}
.task-card-must {
  border: 1px solid var(--keio-red);
  background: #fdf4f6;
}

.task-card-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.task-badge {
  font-size: 0.68rem;
  font-weight: 700;
  color: #fff;
  background: var(--keio-red);
  padding: 3px 10px;
  border-radius: 10px;
  white-space: nowrap;
}
.task-badge-optional {
  background: var(--keio-blue);
}

.task-card h4 {
  font-family: var(--font-serif);
  font-size: 1rem;
  color: var(--keio-blue-deep);
  margin: 0;
}

.task-card p {
  font-size: 0.86rem;
  margin: 0;
}

/* ---------- Contact ---------- */
.section-contact {
  background: linear-gradient(160deg, var(--keio-blue-deep), var(--keio-blue) 60%, var(--keio-red-deep));
  color: #fff;
}

.contact-lead {
  text-align: center;
  color: rgba(255,255,255,0.88);
  margin-bottom: 44px;
}

.contact-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.contact-panel-single {
  grid-template-columns: 1fr;
  max-width: 420px;
  margin: 0 auto;
}

.contact-block {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: 4px;
  padding: 32px;
  text-align: center;
}
.contact-block h3 {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  margin: 0 0 12px;
  color: var(--gold);
}
.contact-block p {
  font-size: 0.88rem;
  color: rgba(255,255,255,0.82);
  margin: 0 0 20px;
}

.contact-email {
  display: inline-block;
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: #fff;
  border-bottom: 1px solid var(--gold);
  padding-bottom: 3px;
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--keio-blue-deep);
  color: rgba(255,255,255,0.72);
  padding: 44px 0 30px;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 22px;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 700;
  color: #fff;
  font-size: 1.05rem;
}
.footer-brand .brand-emblem { width: 32px; height: 32px; font-size: 0.9rem; }

.footer-nav {
  display: flex;
  gap: 22px;
  flex-wrap: wrap;
  justify-content: center;
  font-size: 0.82rem;
}
.footer-nav a:hover { color: var(--gold); }

.footer-copy {
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  color: rgba(255,255,255,0.45);
  margin: 0;
}

/* ===========================================================
   Responsive
   =========================================================== */
@media (max-width: 860px) {
  .task-cards { grid-template-columns: 1fr; }
  .contact-panel { grid-template-columns: 1fr; }
}

@media (max-width: 980px) {
  .sp-only { display: inline; }

  .nav-toggle { display: flex; }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--paper-line);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease;
    box-shadow: 0 12px 20px rgba(0,0,51,0.08);
  }
  .site-nav.open { max-height: 480px; }

  .site-nav ul {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 24px 20px;
  }
  .site-nav li { border-bottom: 1px solid var(--paper-line); }
  .site-nav li:last-child { border-bottom: none; padding-top: 12px; }
  .nav-link { display: block; padding: 16px 4px; }
  .nav-cta { text-align: center; }

  .section { padding: 64px 0; }
  .section-title .ja { font-size: 1.55rem; }

  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-actions .btn { text-align: center; }

  .news-item { flex-direction: column; gap: 8px; }

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

@media (max-width: 480px) {
  .container { padding: 0 20px; }
  .brand-sub { display: none; }
}