:root{
    --washi:#F3ECDB;
    --washi-deep:#E7DBBC;
    --sumi:#26221B;
    --sumi-soft:#5A5346;
    --ai:#1B4B6B;
    --ai-deep:#0F3348;
    --ai-pale:#DCE7EA;
    --shu:#C13B2A;
    --shu-deep:#8F2B1F;
    --shu-pale:#F3DDD5;
    --gold:#AD7E2B;
    --gold-deep:#7C5A1C;
    --gold-pale:#EFE1C2;
    --font-d:'Shippori Antique B1', serif;
    --font-b:'Zen Kaku Gothic New', sans-serif;
  }
  *{box-sizing:border-box;}
  html{scroll-behavior:smooth;}
  body{
    margin:0;
    background:var(--washi);
    color:var(--sumi);
    font-family:var(--font-b);
    line-height:1.8;
    background-image:
      radial-gradient(ellipse at 20% 10%, rgba(255,255,255,.35), transparent 45%),
      radial-gradient(ellipse at 80% 90%, rgba(0,0,0,.03), transparent 50%),
      url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='56' height='97' viewBox='0 0 56 97'%3E%3Cg fill='none' stroke='%2326221B' stroke-opacity='0.05' stroke-width='1'%3E%3Cpath d='M28 0 56 16 56 48 28 64 0 48 0 16Z'/%3E%3Cpath d='M28 0 28 32 0 48 M28 32 56 48 M28 32 28 64 M0 16 28 32 M56 16 28 32'/%3E%3Cpath d='M28 64 56 80 56 97 M28 64 0 80 0 97 M28 64 28 97'/%3E%3C/g%3E%3C/svg%3E");
    background-size:auto, auto, 112px 194px;
    background-repeat:no-repeat, no-repeat, repeat;
  }
  a{color:inherit;}
  h1,h2,h3{font-family:var(--font-d);margin:0;}
  .wrap{max-width:1040px;margin:0 auto;padding:0 24px;}

  /* ---------- HERO ---------- */
  .hero{
    position:relative;overflow:hidden;
    background:linear-gradient(180deg,var(--ai-deep) 0%, var(--ai) 55%, var(--ai) 100%);
    color:var(--washi);
    padding:76px 24px 40px;
    text-align:center;
  }
  .hero::before{
    content:"";position:absolute;inset:0;
    background-image:repeating-radial-gradient(circle at 0 0, transparent 0, transparent 26px, rgba(255,255,255,.035) 27px);
    opacity:.5;
  }
  .hero .eyebrow{
    letter-spacing:.5em;font-size:12px;color:var(--gold-pale);
    font-family:var(--font-b);font-weight:500;
    padding-left:.5em;margin-bottom:22px;
  }
  .hero h1{
    font-size:clamp(34px,6vw,58px);
    font-weight:800;letter-spacing:.08em;line-height:1.35;
    text-shadow:0 2px 18px rgba(0,0,0,.25);
  }
  .hero h1 span{display:block;font-size:.42em;letter-spacing:.5em;color:var(--gold-pale);margin-top:10px;font-weight:500;}
  .hero p.lead{max-width:560px;margin:26px auto 0;color:#E7EEF0;font-size:15px;}
  .hero-seal{
    width:78px;height:78px;margin:34px auto 0;position:relative;
  }
  .hero-seal svg{width:100%;height:100%;}
  .tategaki{
    position:absolute;top:50%;transform:translateY(-50%);
    writing-mode:vertical-rl;text-orientation:mixed;
    font-family:var(--font-d);font-size:14px;letter-spacing:.5em;
    color:rgba(239,225,194,.4);z-index:2;user-select:none;
    display:none;
  }
  .tategaki.left{left:22px;}
  .tategaki.right{right:22px;}
  @media(min-width:820px){.tategaki{display:block;}}

  /* noren nav */
  .noren-nav{
    position:relative;z-index:2;
    display:flex;justify-content:center;gap:0;flex-wrap:wrap;
    margin-top:40px;
  }
  .noren-nav a{
    text-decoration:none;font-family:var(--font-d);font-weight:700;
    color:var(--washi);background:rgba(0,0,0,.18);
    border-left:1px solid rgba(255,255,255,.25);
    padding:14px 26px;font-size:15px;letter-spacing:.15em;
    transition:background .25s ease, transform .2s ease;
  }
  .noren-nav a:first-child{border-left:none;}
  .noren-nav a:hover{background:rgba(255,255,255,.14);transform:translateY(-2px);}

  /* ---------- STAMP BOOK (goshuincho) ---------- */
  .stampbook{
    position:fixed;right:16px;bottom:16px;z-index:50;
    display:flex;align-items:center;gap:10px;
    background:var(--sumi);color:var(--washi);
    border-radius:999px;padding:10px 16px 10px 10px;
    box-shadow:0 8px 24px rgba(0,0,0,.28);
    font-family:var(--font-b);font-size:12px;font-weight:700;
    letter-spacing:.08em;
    cursor:default;
  }
  .stampbook .slots{display:flex;gap:6px;}
  .slot{
    width:26px;height:26px;border-radius:50%;
    border:1.5px dashed rgba(255,255,255,.35);
    display:flex;align-items:center;justify-content:center;
    font-family:var(--font-d);font-size:12px;color:rgba(255,255,255,.35);
    transition:all .4s ease;
  }
  .slot.filled{
    border:none;background:var(--shu);color:#fff;
    box-shadow:0 0 0 2px rgba(255,255,255,.15) inset;
    transform:scale(1.05);
  }

  /* ---------- SECTION GENERIC ---------- */
  section.chapter{padding:86px 0 30px;position:relative;overflow:hidden;}
  .chapter-head{text-align:center;max-width:640px;margin:0 auto 54px;position:relative;}
  .watermark{
    position:absolute;top:-.35em;left:50%;transform:translateX(-50%);
    font-family:var(--font-d);font-weight:400;
    font-size:clamp(140px,22vw,260px);
    line-height:1;color:var(--sumi);opacity:.045;
    pointer-events:none;user-select:none;z-index:0;white-space:nowrap;
  }
  .chapter-head > *{position:relative;z-index:1;}
  .chapter-num{
    display:inline-flex;align-items:center;justify-content:center;
    width:56px;height:56px;border-radius:50%;
    font-family:var(--font-d);font-size:22px;font-weight:700;
    margin-bottom:18px;color:#fff;position:relative;
  }
  .chapter-num::before{
    content:"";position:absolute;inset:-7px;border-radius:50%;
    border:1px solid currentColor;opacity:.35;
  }
  .chapter-title{font-size:clamp(24px,4vw,34px);font-weight:800;letter-spacing:.06em;}
  .chapter-sub{margin-top:6px;font-size:13px;letter-spacing:.2em;color:var(--sumi-soft);}
  .chapter-desc{margin-top:20px;font-size:14.5px;color:var(--sumi-soft);}

  #japan .chapter-num{background:var(--ai);}
  #fukuoka .chapter-num{background:var(--shu);}
  #overseas .chapter-num{background:var(--gold);}

  .divider{
    height:22px;margin:0 auto;max-width:1040px;
    background-repeat:repeat-x;background-position:center;background-size:20px 22px;opacity:.7;
  }
  .divider.ai{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='22'%3E%3Cg fill='none' stroke='%231B4B6B' stroke-width='1.1'%3E%3Cpath d='M0,20 A10,10 0 0 1 20,20'/%3E%3Cpath d='M4,20 A6,6 0 0 1 16,20'/%3E%3Cpath d='M7,20 A3,3 0 0 1 13,20'/%3E%3C/g%3E%3C/svg%3E");}
  .divider.shu{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='22'%3E%3Cg fill='none' stroke='%23C13B2A' stroke-width='1.1'%3E%3Cpath d='M0,20 A10,10 0 0 1 20,20'/%3E%3Cpath d='M4,20 A6,6 0 0 1 16,20'/%3E%3Cpath d='M7,20 A3,3 0 0 1 13,20'/%3E%3C/g%3E%3C/svg%3E");}
  .divider.gold{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='22'%3E%3Cg fill='none' stroke='%23AD7E2B' stroke-width='1.1'%3E%3Cpath d='M0,20 A10,10 0 0 1 20,20'/%3E%3Cpath d='M4,20 A6,6 0 0 1 16,20'/%3E%3Cpath d='M7,20 A3,3 0 0 1 13,20'/%3E%3C/g%3E%3C/svg%3E");}

  /* ---------- CHAPTER 1: FLIP CARDS ---------- */
  .card-grid{
    display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));
    gap:20px;max-width:960px;margin:0 auto;
  }
  .flip-card{perspective:1200px;height:210px;cursor:pointer;}
  .flip-inner{
    position:relative;width:100%;height:100%;
    transition:transform .65s cubic-bezier(.2,.8,.2,1);
    transform-style:preserve-3d;
  }
  .flip-card.flipped .flip-inner{transform:rotateY(180deg);}
  .flip-face{
    position:absolute;inset:0;backface-visibility:hidden;
    border-radius:10px;padding:22px;
    display:flex;flex-direction:column;justify-content:center;
  }
  .flip-front{
    background:#fff;border:1px solid var(--washi-deep);
    box-shadow:0 6px 18px rgba(27,75,107,.08);
    align-items:center;text-align:center;gap:10px;
    position:relative;
  }
  .flip-front::before{
    content:"";position:absolute;top:0;left:50%;transform:translateX(-50%);
    width:26px;height:6px;background:var(--ai);border-radius:0 0 4px 4px;
  }
  .flip-front .kanji-icon{font-family:var(--font-d);font-size:34px;color:var(--ai);font-weight:700;}
  .flip-front .item-name{font-family:var(--font-d);font-size:18px;font-weight:700;}
  .flip-front .hint{font-size:11px;color:var(--sumi-soft);letter-spacing:.1em;}
  .flip-back{
    background:var(--ai);color:#fff;transform:rotateY(180deg);
    font-size:13px;
  }
  .flip-back b{display:block;font-family:var(--font-d);font-size:15px;margin-bottom:8px;color:var(--gold-pale);}

  /* ---------- CHAPTER 2: JOURNEY TIMELINE ---------- */
  .journey{position:relative;max-width:760px;margin:0 auto;padding:10px 0;}
  .journey::before{
    content:"";position:absolute;left:50%;top:0;bottom:0;width:2px;
    background:repeating-linear-gradient(180deg,var(--shu) 0 8px, transparent 8px 16px);
    transform:translateX(-50%);
  }
  .stop{position:relative;width:calc(50% - 34px);margin-bottom:26px;}
  .stop:nth-child(odd){margin-left:0;text-align:right;}
  .stop:nth-child(even){margin-left:calc(50% + 34px);text-align:left;}
  .stop-dot{
    position:absolute;top:14px;width:14px;height:14px;border-radius:50%;
    background:var(--shu);border:3px solid var(--washi);box-shadow:0 0 0 1px var(--shu);
  }
  .stop:nth-child(odd) .stop-dot{right:-41px;}
  .stop:nth-child(even) .stop-dot{left:-41px;}
  .stop-card{
    background:#fff;border:1px solid var(--washi-deep);border-radius:10px;
    padding:16px 20px;cursor:pointer;box-shadow:0 4px 14px rgba(193,59,42,.06);
    transition:box-shadow .2s ease;
  }
  .stop-card:hover{box-shadow:0 8px 20px rgba(193,59,42,.14);}
  .stop-loc{
    display:inline-flex;align-items:center;justify-content:center;
    font-family:var(--font-d);font-size:12px;background:var(--shu);color:#fff;
    width:auto;padding:4px 12px;border-radius:3px;font-weight:700;letter-spacing:.05em;margin-bottom:8px;
    box-shadow:0 0 0 1px rgba(255,255,255,.4) inset;
  }
  .stop-name{font-family:var(--font-d);font-size:17px;font-weight:700;}
  .stop-detail{
    max-height:0;overflow:hidden;transition:max-height .4s ease, margin-top .4s ease;
    font-size:13px;color:var(--sumi-soft);text-align:left;margin-top:0;
  }
  .stop-card.open .stop-detail{max-height:200px;margin-top:10px;}
  .stop-arrow{font-size:11px;color:var(--shu);margin-top:6px;letter-spacing:.05em;}

  @media(max-width:640px){
    .journey::before{left:14px;}
    .stop, .stop:nth-child(odd), .stop:nth-child(even){
      width:calc(100% - 40px);margin-left:40px;text-align:left;
    }
    .stop:nth-child(odd) .stop-dot,.stop:nth-child(even) .stop-dot{left:-30px;right:auto;}
  }

  /* ---------- CHAPTER 3: TWO-CHOICE QUIZ ---------- */
  .quizzes3{max-width:720px;margin:0 auto;display:flex;flex-direction:column;gap:18px;}
  .q3-card{
    background:#fff;border:1px solid var(--washi-deep);border-radius:12px;
    padding:22px;box-shadow:0 6px 18px rgba(173,126,43,.08);
  }
  .q3-top{display:flex;align-items:center;gap:14px;flex-wrap:wrap;}
  .q3-badge{
    font-family:var(--font-d);font-size:24px;color:var(--gold-deep);
    background:var(--gold-pale);width:48px;height:48px;border-radius:50%;
    display:flex;align-items:center;justify-content:center;flex:none;
  }
  .q3-name{font-family:var(--font-d);font-size:19px;font-weight:700;}
  .q3-question{font-size:13px;color:var(--sumi-soft);margin-top:2px;}
  .q3-choices{display:flex;gap:10px;margin-top:16px;}
  .q3-choices button{
    flex:1;padding:11px;border-radius:8px;border:1.5px solid var(--gold);
    background:#fff;color:var(--gold-deep);font-family:var(--font-b);font-weight:700;
    font-size:14px;cursor:pointer;transition:all .2s ease;letter-spacing:.05em;
  }
  .q3-choices button:hover{background:var(--gold-pale);}
  .q3-choices button:disabled{cursor:default;}
  .q3-choices button.chosen-right{background:var(--ai);border-color:var(--ai);color:#fff;}
  .q3-choices button.chosen-wrong{background:var(--shu);border-color:var(--shu);color:#fff;}
  .q3-reveal{
    display:none;margin-top:14px;padding-top:14px;border-top:1px dashed var(--washi-deep);
    font-size:13px;color:var(--sumi-soft);
  }
  .q3-reveal b{color:var(--sumi);font-family:var(--font-d);font-size:14.5px;}
  .q3-card.answered .q3-reveal{display:block;}

  /* ---------- QUIZ (chapter recap, multi-choice) ---------- */
  .recap{max-width:640px;margin:56px auto 0;background:#fff;border-radius:14px;
    padding:30px 26px;border:1px solid var(--washi-deep);}
  .recap h3{font-size:16px;letter-spacing:.1em;margin-bottom:4px;}
  .recap .sub{font-size:12px;color:var(--sumi-soft);margin-bottom:20px;}
  .rq{margin-bottom:22px;}
  .rq p{font-weight:700;font-size:14.5px;margin-bottom:10px;}
  .rq .opts{display:grid;grid-template-columns:1fr 1fr;gap:8px;}
  .rq .opts button{
    padding:10px;border-radius:8px;border:1.5px solid var(--washi-deep);
    background:var(--washi);font-family:var(--font-b);font-size:13px;cursor:pointer;
    text-align:left;transition:all .15s ease;
  }
  .rq .opts button:hover{border-color:var(--sumi-soft);}
  .rq .opts button.right{background:var(--ai);border-color:var(--ai);color:#fff;}
  .rq .opts button.wrong{background:var(--shu);border-color:var(--shu);color:#fff;}
  .rq .opts button:disabled{cursor:default;}
  .recap-progress{
    text-align:center;font-size:12px;color:var(--sumi-soft);margin-top:8px;letter-spacing:.05em;
  }
  #japan .recap, #fukuoka .recap{border-top:4px solid var(--ai);}
  #fukuoka .recap{border-top-color:var(--shu);}

  /* ---------- CERTIFICATE ---------- */
  .cert-wrap{padding:70px 24px 100px;text-align:center;}
  .mizuhiki{width:120px;margin:0 auto 30px;}
  .mizuhiki svg{width:100%;height:auto;}
  .certificate{
    max-width:560px;margin:0 auto;background:var(--washi);
    border:3px double var(--gold);border-radius:6px;padding:46px 32px;
    position:relative;box-shadow:0 14px 40px rgba(0,0,0,.12);
    opacity:.35;filter:grayscale(1);transition:opacity .6s ease, filter .6s ease;
  }
  .certificate.unlocked{opacity:1;filter:none;}
  .certificate h3{font-size:26px;letter-spacing:.2em;color:var(--sumi);}
  .certificate .sub{font-size:12px;letter-spacing:.3em;color:var(--sumi-soft);margin-top:8px;}
  .certificate p.msg{margin-top:24px;font-size:13.5px;color:var(--sumi-soft);}
  .certificate .final-hanko{
    width:80px;height:80px;margin:26px auto 0;
    border-radius:46% 54% 52% 48%/48% 52% 45% 55%;
    background:var(--shu);color:#fff;display:flex;align-items:center;justify-content:center;
    font-family:var(--font-d);font-weight:800;font-size:15px;letter-spacing:.1em;
    transform:rotate(-8deg);box-shadow:0 0 0 3px rgba(193,59,42,.15) inset;
    line-height:1.3;text-align:center;
  }
  .cert-lock{font-size:12px;color:var(--sumi-soft);margin-top:14px;letter-spacing:.05em;}

  footer{
    text-align:center;padding:30px 24px 90px;font-size:11.5px;color:var(--sumi-soft);
  }
  footer .note{max-width:520px;margin:0 auto 8px;}