:root {
        --navy: #071a2d;
        --navy-2: #0c2947;
        --blue: #1268a8;
        --cyan: #36c6d3;
        --ice: #edf8fa;
        --paper: #f7fafc;
        --ink: #172536;
        --muted: #5b6b7c;
        --line: #d7e3eb;
        --white: #fff;
        --shadow: 0 18px 50px rgba(4, 27, 48, .12);
        --radius: 18px;
        --max: 1120px;
      }
      
      * { box-sizing: border-box; }
      html { scroll-behavior: smooth; }
      body {
        margin: 0;
        color: var(--ink);
        background: var(--paper);
        font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
        line-height: 1.8;
        -webkit-font-smoothing: antialiased;
      }
      a { color: inherit; }
      .container { width: min(calc(100% - 40px), var(--max)); margin-inline: auto; }
      .skip-link { position: fixed; top: -100px; left: 16px; z-index: 100; padding: 10px 16px; background: #fff; color: #000; }
      .skip-link:focus { top: 16px; }
      
      header {
        position: sticky; top: 0; z-index: 50;
        background: rgba(7, 26, 45, .92);
        border-bottom: 1px solid rgba(255,255,255,.12);
        backdrop-filter: blur(12px);
      }
      .nav { min-height: 70px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
      .brand { text-decoration: none; color: #fff; font-weight: 800; letter-spacing: .03em; font-size: 1.08rem; white-space: nowrap; }
      .brand span { color: var(--cyan); }
      nav ul { display: flex; flex-wrap: wrap; gap: 22px; list-style: none; padding: 0; margin: 0; }
      nav a { color: #d9e9f4; text-decoration: none; font-size: .92rem; }
      nav a:hover, nav a:focus-visible { color: #fff; text-decoration: underline; text-underline-offset: 5px; }
      
      .hero {
        position: relative; overflow: hidden; color: #fff;
        background:
          radial-gradient(circle at 78% 20%, rgba(54,198,211,.28), transparent 28%),
          radial-gradient(circle at 8% 86%, rgba(18,104,168,.5), transparent 31%),
          linear-gradient(135deg, #061728 0%, #0b2d4f 58%, #0f506c 100%);
      }
      .hero::before, .hero::after {
        content: ""; position: absolute; border: 1px solid rgba(93,224,232,.26); border-radius: 50%;
      }
      .hero::before { width: 520px; height: 520px; right: -170px; top: -190px; }
      .hero::after { width: 320px; height: 320px; right: 15%; bottom: -240px; }
      .hero-inner { position: relative; z-index: 1; min-height: auto; padding: 96px 0 40px; display: grid; align-content: start; }
      .eyebrow { margin: 0 0 14px; color: #95f1f2; font-size: .82rem; font-weight: 800; letter-spacing: .17em; text-transform: uppercase; }
      h1 { margin: 0; font-size: clamp(3rem, 8vw, 6.8rem); line-height: .98; letter-spacing: -.045em; }
      h1 span { color: var(--cyan); }
      .lead { max-width: 780px; margin: 28px 0 0; font-size: clamp(1.25rem, 2.3vw, 1.85rem); line-height: 1.55; font-weight: 650; }
      .hero-copy { max-width: 720px; margin: 17px 0 0; color: #c9dbe8; font-size: 1.03rem; }
      .hero-meta { display: flex; flex-wrap: wrap; gap: 12px; margin: 34px 0 0; }
      .pill { display: inline-flex; align-items: center; gap: 9px; padding: 9px 15px; border: 1px solid rgba(255,255,255,.2); border-radius: 999px; background: rgba(255,255,255,.08); color: #eefaff; font-size: .94rem; }
      .pill-main {
        background: rgba(54, 198, 211, 0.15);
        border-color: rgba(54, 198, 211, 0.55);
      }
       
      .pill-main strong {
        color: #95f1f2;
      }
      .pill::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 0 5px rgba(54,198,211,.13); }
      .cta-row { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 34px; }
      .registration-notice strong { color: #fff; }
      .button { display: inline-block; min-width: 176px; padding: 13px 20px; border-radius: 10px; text-align: center; text-decoration: none; font-weight: 800; transition: transform .15s, background .15s; }
      .button:hover { transform: translateY(-2px); }
      .button-primary { color: #052034; background: var(--cyan); }
      .button-secondary { color: #fff; border: 1px solid rgba(255,255,255,.35); background: rgba(255,255,255,.07); }
      
      section { padding: 90px 0; }
      .section-kicker { margin: 0 0 8px; color: var(--blue); font-size: .78rem; font-weight: 850; letter-spacing: .16em; text-transform: uppercase; }
      h2 { margin: 0 0 24px; color: var(--navy); font-size: clamp(2rem, 4.2vw, 3.25rem); line-height: 1.25; letter-spacing: -.025em; }
      .intro { max-width: 830px; color: var(--muted); font-size: 1.08rem; }
      
      .purpose-wrap { display: grid; grid-template-columns: .85fr 1.15fr; gap: 64px; align-items: start; }
      .statement { position: sticky; top: 110px; padding: 30px; color: #fff; background: var(--navy); border-radius: var(--radius); box-shadow: var(--shadow); }
      .statement strong { display: block; margin-bottom: 12px; color: var(--cyan); font-size: 1.28rem; }
      .statement p { margin: 0; }
      .prose p { margin: 0 0 22px; }
      
      .context { background: #fff; border-block: 1px solid var(--line); }
      .cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 42px; }
      .card { min-height: 250px; padding: 28px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; box-shadow: 0 10px 28px rgba(7,26,45,.06); }
      .card-num { display: grid; place-items: center; width: 44px; height: 44px; margin-bottom: 24px; border-radius: 12px; color: #fff; background: var(--blue); font-size: .9rem; font-weight: 850; }
      .card h3 { margin: 0 0 12px; color: var(--navy); font-size: 1.22rem; line-height: 1.5; }
      .card p { margin: 0; color: var(--muted); font-size: .96rem; }
      
      .event { color: #fff; background: var(--navy); }
      .event h2, .event .section-kicker { color: #fff; }
      .event-grid { display: grid; grid-template-columns: 1fr; gap: 48px; align-items: start; }
      .facts { margin: 0; border-top: 1px solid rgba(255,255,255,.18); }
      .fact { display: grid; grid-template-columns: 120px 1fr; gap: 22px; padding: 21px 0; border-bottom: 1px solid rgba(255,255,255,.18); }
      .fact dt { color: #8ddfe6; font-weight: 800; }
      .fact dd { margin: 0; color: #f0f7fb; }
      .venue-name { display: block; font-weight: 800; }
      .venue-address { display: block; margin-top: 8px; font-style: normal; color: #dceaf3; }
      .access-details { display: grid; gap: 12px; margin-top: 16px; padding-top: 15px; border-top: 1px solid rgba(255,255,255,.16); }
      .access-group strong { display: block; margin-bottom: 3px; color: #8ddfe6; font-size: .9rem; }
      .access-group p { margin: 0; color: #dceaf3; font-size: .91rem; line-height: 1.7; }
      .map-link { display: inline-flex; align-items: center; margin-top: 16px; padding: 9px 14px; border: 1px solid rgba(255,255,255,.32); border-radius: 9px; color: #fff; background: rgba(255,255,255,.08); text-decoration: none; font-weight: 750; font-size: .9rem; }
      .map-link:hover, .map-link:focus-visible { background: rgba(255,255,255,.16); text-decoration: underline; text-underline-offset: 4px; }
      .note { color: #bad0df; font-size: .9rem; }
      .program-section { background: #fff; border-bottom: 1px solid var(--line); }
      .program { max-width: 900px; padding: 36px; border: 1px solid var(--line); border-radius: var(--radius); color: var(--ink); background: #fff; box-shadow: var(--shadow); }
      .program h3 { margin: 0 0 18px; color: var(--navy); font-size: 1.35rem; }
      .program ul { display: grid; gap: 12px; padding: 0; margin: 0; list-style: none; }
      .program li { position: relative; padding-left: 24px; }
      .program li::before { content: ""; position: absolute; top: .72em; left: 0; width: 10px; height: 3px; background: var(--cyan); }
      .program-list { display: grid; gap: 12px; margin-top: 22px; }
      .program-item { padding: 16px 18px; border: 1px solid var(--line); border-radius: 11px; background: #f8fbfc; }
      .program-item time { display: block; color: var(--blue); font-size: .82rem; font-weight: 800; }
      .program-item strong { display: block; margin-top: 3px; color: var(--navy); }
/*
      .program-item span { display: block; color: var(--muted); font-size: .9rem; }
*/
.program-item span {
  display: block;
  margin-top: 8px;
  color: var(--navy);
  font-size: 0.98rem;
  font-weight: 700;
  line-height: 1.6;
}
      .program-item.social { border-color: #9ed9df; background: var(--ice); }
      
      .topics { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 30px; }
      .topic { padding: 8px 14px; border: 1px solid #bfd6e3; border-radius: 999px; color: #16496b; background: var(--ice); font-size: .9rem; font-weight: 700; }
      .speaker-note { margin-top: 36px; padding: 24px 26px; border-left: 5px solid var(--cyan); border-radius: 0 14px 14px 0; background: #fff; box-shadow: 0 8px 24px rgba(7,26,45,.07); }
      .speaker-note strong { color: var(--navy); }
      .program .speaker-note { margin-top: 28px; }
      
      .partners { background: #fff; border-top: 1px solid var(--line); }
      .organization-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 34px; }
      .organization-card { padding: 25px; border: 1px solid var(--line); border-radius: 14px; background: #f8fbfc; }
      .organization-card h3 { margin: 0 0 9px; color: var(--blue); font-size: .86rem; letter-spacing: .08em; }
      .organization-card p { margin: 0; color: var(--navy); font-weight: 750; }
      .sponsor-heading { margin: 48px 0 18px; color: var(--navy); font-size: 1.55rem; }
      /*
      .partner-logos { min-height: 220px; padding: 28px; display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); align-items: center; gap: 24px; border: 2px dashed #bfd2dd; border-radius: var(--radius); background: #f8fbfc; }
      .partner-logo { min-height: 110px; padding: 18px; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 12px; border-radius: 12px; background: #fff; text-decoration: none; }

      .partner-logo-name { text-align: center; color: var(--navy); font-size: .88rem; font-weight: 700; line-height: 1.5; }
      */
      .partner-logo img { display: block; width: auto; max-width: 100%; height: auto; max-height: 72px; object-fit: contain; }
      .partner-placeholder { grid-column: 1 / -1; text-align: center; color: #71808e; }
      .partner-placeholder p { margin: 0; }
      .partner-placeholder span { display: block; margin-top: 7px; font-size: .88rem; color: #91a0ab; }
      
      .contact { text-align: center; background: linear-gradient(180deg, #edf8fa 0%, #f7fafc 100%); }
      .contact-box { max-width: 780px; margin: auto; padding: 50px 34px; border: 1px solid #cddfe7; border-radius: 24px; background: #fff; box-shadow: var(--shadow); }
      .mail { display: inline-block; margin-top: 10px; color: var(--blue); font-size: clamp(1rem, 3vw, 1.4rem); font-weight: 850; word-break: break-all; text-underline-offset: 5px; }
      
       
      .button-register {
        font-size: 1.15rem;
        padding: 16px 42px;
        border-radius: 999px;
        box-shadow: 0 8px 24px rgba(0,0,0,.18);
        background: linear-gradient(
          135deg,
          #ffb300,
          #ff6f00
          );
        color: #fff;
      }
      
      .registration-notice strong {
        color: #fff;
      }
      
      .registration-block {
        margin: 40px 0 48px;
        margin-bottom: 32px;
      }
      
      .registration-notice {
        margin: 0 0 18px;
        text-align: center;
      }
      
      .registration-cta {
        text-align: center;
        margin: 12px 0;
      }
      
      .button.button-primary.button-register {
        display: inline-flex;
        min-width: 380px;
        justify-content: center;
        padding: 20px 48px;
        font-size: 1.25rem;
        font-weight: 700;
        
        background: linear-gradient(
          135deg,
          #ffb300,
          #ff6f00
          );
        
        color: #fff;
        border-radius: 16px;
        
        box-shadow:
          0 12px 32px rgba(255,111,0,.35);
        
        transition:
          transform .2s ease,
          box-shadow .2s ease;
      }
      
      .button.button-primary.button-register:hover {
        transform: translateY(-2px);
        box-shadow:
          0 16px 40px rgba(255,111,0,.45);
      }
      
      /* --------------------------------------------------
   Day1 関連イベント（時空間同期シンポジウム）
   -------------------------------------------------- */
      
      .related-program {
        margin-top: 32px;
        padding: 20px 22px;
        border: 1px solid var(--line);
        border-left: 4px solid #7a98aa;
        border-radius: 12px;
        background: #fbfcfd;
      }
      
      .related-program-label {
        margin: 0;
        color: #6a8a9c;
        font-size: .72rem;
        font-weight: 800;
        letter-spacing: .08em;
        text-transform: uppercase;
      }
      
      .related-program-header h4 {
        margin: 0;
        color: var(--navy);
        font-size: 1.1rem;
        line-height: 1.5;
      }
      
      .related-program-intro {
        margin: 6px 0 0;
        color: var(--muted);
        font-size: .85rem;
        line-height: 1.7;
      }
      
      .related-program-organizer {
        margin: 10px 0 0;
        color: #738694;
        font-size: .78rem;
        line-height: 1.7;
      }
      
      .related-program-timetable {
        border-top: 1px solid var(--line);
      }
      
      .related-program-item {
        grid-template-columns: 1fr;
        display: grid;
        gap: 4px;
      }
        .related-program-item:last-child {
            border-bottom: none;
        }
        
        .related-program-item time {
          display: block;
          color: var(--blue);
          font-size: .78rem;
          font-weight: 800;
          white-space: nowrap;
        }
        
        .related-program-detail h5 {
          margin: 0;
          color: var(--navy);
          font-size: .92rem;
          line-height: 1.6;
        }
        
        .related-program-type {
          margin: 0 0 4px;
          color: #6a8a9c;
          font-size: .7rem;
          font-weight: 700;
          letter-spacing: .06em;
        }
/*
        .related-program-speaker {
          margin: 5px 0 0;
          color: var(--muted);
          font-size: .82rem;
          line-height: 1.6;
        }
*/
.related-program-speaker {
  margin: 8px 0 0;
  color: #173a56;
  font-size: .9rem;
  font-weight: 700;
  line-height: 1.6;
}
        .related-program-item--minor {
          background: #fafcfd;
        }
        
        .related-program-item--minor .related-program-detail h5 {
          color: #7c8d99;
          font-size: .85rem;
        }
        
        .related-program-item--highlight {
          background: #f3f9fb;
        }
        
        .related-program-footer {
          margin-top: 14px;
          padding-top: 14px;
          border-top: 1px solid var(--line);
          color: #6f828f;
          font-size: .74rem;
          line-height: 1.8;
        }
        
        .related-program-footer p {
          margin: 0 0 8px;
        }
        
        .related-program-footer a {
          color: var(--blue);
          font-weight: 700;
          text-decoration: underline;
          text-underline-offset: 4px;
        }
        
        /* Day1 と Day2 の間隔 */
        .program-day + .program-day {
          margin-top: 72px;
        }
        .program-day-heading {
          margin-bottom: 20px;
        }
        
        .program-day-label {
          margin: 0;
          color: var(--blue);
          font-size: .8rem;
          font-weight: 800;
          letter-spacing: .12em;
        }
        footer { padding: 32px 0; color: #a9bfce; background: #04111e; font-size: .86rem; }
        .footer-row { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
        
        .abstract {
          margin-top: 0.8rem;
        }
        
        .abstract summary {
          cursor: pointer;
          color: #0a5cff;
          font-weight: 600;
        }
        
        .abstract p {
          margin-top: 0.6rem;
          line-height: 1.7;
        }
        .partner-logos {
          display: grid;
          grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
          gap: 36px;
          margin-top: 32px;
        }
        
        .partner-logo {
          display: flex;
          flex-direction: column;
          align-items: center;
          text-align: center;
          text-decoration: none;
          color: inherit;
          padding: 20px;
          transition: transform 0.2s ease;
        }
        
        .partner-logo:hover {
          transform: translateY(-2px);
        }
        
        .partner-logo-image {
          width: 280px;
          height: 100px;
          
          display: flex;
          align-items: center;
          justify-content: center;
          
          margin-bottom: 12px;
        }
        
        .partner-logo-image img {
          max-width: 100%;
          max-height: 100%;
          width: auto;
          height: auto;
          object-fit: contain;
          display: block;
        }
        
        .partner-logo-name {
          display: block;
          text-align: center;
          color: var(--navy);
          font-size: 0.95rem;
          font-weight: 600;
          line-height: 1.4;
        }
        
        .abstract {
          margin-top: 12px;
        }
        
        .abstract p {
          margin: 0;
          padding: 14px 16px;
          background: #f8fbfc;
          border-left: 4px solid var(--cyan);
          border-radius: 0 10px 10px 0;
          color: var(--muted);
          font-size: 0.92rem;
          line-height: 1.8;
        }

        @media (max-width: 768px) {
          
          .partner-logos {
            grid-template-columns: 1fr;
            gap: 28px;
          }
          
          .partner-logo-image {
            width: 240px;
            height: 90px;
          }
          
        }
        
        @media (max-width: 820px) {
          nav { display: block; }
          .hero-inner { min-height: 580px; padding: 76px 0 66px; }
          .purpose-wrap, .event-grid { grid-template-columns: 1fr; gap: 34px; }
          .statement { position: static; }
          .cards, .organization-grid { grid-template-columns: 1fr; }
          section { padding: 68px 0; }
        }
        @media (max-width: 520px) {
          
          .container {
            width: min(calc(100% - 28px), var(--max));
          }
          
          .hero-meta {
            display: grid;
          }
          
          .button {
            width: 100%;
          }
          
          .fact {
            grid-template-columns: 1fr;
            gap: 3px;
          }
          
          .card,
          .program {
            padding: 23px;
          }
          
          /* 時空間同期シンポジウム */
          
          .related-program {
            padding: 16px;
          }
          
          .related-program-header,
          .related-program-item {
            grid-template-columns: 1fr;
            gap: 4px;
          }
          
          .related-program-label {
            margin-bottom: 4px;
          }
          
          .related-program-item {
            padding: 12px 4px;
          }
          
          .related-program-item time {
            font-size: .74rem;
          }
          
          .related-program-header h4 {
            font-size: 1rem;
          }
        }
        @media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .button { transition: none; } }

.mobile-menu {
  display: none;
}

.mobile-menu summary {
  list-style: none;
  cursor: pointer;
  color: #fff;
  font-weight: 700;
  padding: 8px 12px;
  border: 1px solid rgba(255,255,255,.25);
  border-radius: 8px;
}

.mobile-menu summary::-webkit-details-marker {
  display: none;
}

@media (max-width: 820px) {

  .desktop-nav {
    display: none !important;
  }

  .mobile-menu {
    display: block;
  }

  .mobile-menu nav {
    display: block !important;
    margin-top: 12px;
  }

  .mobile-menu nav ul {
    display: flex;
    flex-direction: column;
    gap: 8px;
    list-style: none;
    margin: 0;
    padding: 0;
  }

  .mobile-menu nav a {
    color: #fff;
  }
}