/* ===== Reset & Base ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#0f1117;--surface:#1a1d27;--card:#222632;--border:#2e3346;
  --text:#e4e6f0;--text2:#9ca3bf;--accent:#6c63ff;--accent2:#8b83ff;
  --green:#22c55e;--red:#ef4444;--orange:#f59e0b;--blue:#3b82f6;
}
html{font-size:16px;scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI','Noto Sans JP',sans-serif;background:var(--bg);color:var(--text);min-height:100vh;line-height:1.6}
.hidden{display:none!important}

/* ===== Top Bar ===== */
#topbar{position:sticky;top:0;z-index:100;display:flex;align-items:center;justify-content:space-between;padding:.75rem 1.25rem;background:rgba(15,17,23,.92);backdrop-filter:blur(12px);border-bottom:1px solid var(--border)}
.logo{font-size:1.4rem;font-weight:800;color:var(--accent);letter-spacing:.05em}
.logo-sub{font-size:.8rem;color:var(--text2);margin-left:.5rem}
#score-display{font-size:.85rem;color:var(--text2)}
#score-display #score-correct{color:var(--green);font-weight:700}
#score-pct{margin-left:.3rem;color:var(--accent);font-weight:600}

/* ===== Home ===== */
#home-screen{max-width:860px;margin:0 auto;padding:1.5rem 1rem 4rem}
.hero{text-align:center;padding:2.5rem 0 1.5rem}
.hero h1{font-size:2rem;font-weight:800;background:linear-gradient(135deg,var(--accent),var(--blue));-webkit-background-clip:text;-webkit-text-fill-color:transparent}
.hero h1 small{font-size:1rem;font-weight:400;-webkit-text-fill-color:var(--text2)}
.hero-desc{color:var(--text2);margin-top:.5rem;font-size:.9rem}

h2{font-size:1.05rem;font-weight:700;margin-bottom:.75rem;color:var(--text2);text-transform:uppercase;letter-spacing:.08em}

/* Mode Cards */
.mode-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:.75rem;margin-bottom:2rem}
.mode-card{background:var(--card);border:1px solid var(--border);border-radius:12px;padding:1.25rem 1rem;cursor:pointer;text-align:center;transition:all .2s}
.mode-card:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:0 4px 20px rgba(108,99,255,.15)}
.mode-icon{font-size:1.8rem;margin-bottom:.4rem}
.mode-title{font-weight:700;font-size:.95rem}
.mode-desc{color:var(--text2);font-size:.78rem;margin-top:.25rem}

/* Category / Year Grid */
.cat-grid,.year-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:.6rem;margin-bottom:2rem}
.cat-btn,.year-btn{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:.85rem 1rem;cursor:pointer;transition:all .2s;display:flex;justify-content:space-between;align-items:center}
.cat-btn:hover,.year-btn:hover{border-color:var(--accent);background:var(--surface)}
.cat-btn .cat-name,.year-btn .year-name{font-weight:600;font-size:.88rem}
.cat-btn .cat-count,.year-btn .year-count{font-size:.78rem;color:var(--text2);background:var(--surface);padding:.15rem .55rem;border-radius:20px}

/* ===== Quiz ===== */
#quiz-screen{max-width:740px;margin:0 auto;padding:1.25rem 1rem 4rem}
.quiz-progress{margin-bottom:1rem}
.progress-bar{height:4px;background:var(--border);border-radius:4px;overflow:hidden}
.progress-fill{height:100%;background:linear-gradient(90deg,var(--accent),var(--blue));transition:width .3s;border-radius:4px}
.progress-text{text-align:right;font-size:.78rem;color:var(--text2);margin-top:.3rem}
.quiz-card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:1.5rem 1.25rem;margin-bottom:1rem}
.q-meta{display:flex;gap:.5rem;margin-bottom:.8rem;flex-wrap:wrap}
.q-category{font-size:.7rem;font-weight:600;text-transform:uppercase;letter-spacing:.06em;padding:.2rem .6rem;border-radius:20px;background:rgba(108,99,255,.15);color:var(--accent)}
.q-year{font-size:.7rem;font-weight:600;padding:.2rem .6rem;border-radius:20px;background:rgba(59,130,246,.12);color:var(--blue)}
.q-text{font-size:1.02rem;line-height:1.75;margin-bottom:1.2rem;white-space:pre-line}

/* Choices */
.choices{display:flex;flex-direction:column;gap:.55rem}
.choice-btn{background:var(--surface);border:1.5px solid var(--border);border-radius:10px;padding:.85rem 1rem;cursor:pointer;text-align:left;font-size:.92rem;line-height:1.55;transition:all .15s;display:flex;align-items:flex-start;gap:.65rem;color:var(--text)}
.choice-btn:hover:not(.disabled){border-color:var(--accent);background:rgba(108,99,255,.06)}
.choice-label{flex-shrink:0;width:1.7rem;height:1.7rem;display:flex;align-items:center;justify-content:center;border-radius:50%;font-size:.78rem;font-weight:700;border:1.5px solid var(--border);transition:all .15s}
.choice-btn:hover:not(.disabled) .choice-label{border-color:var(--accent);color:var(--accent)}
.choice-btn.correct{border-color:var(--green);background:rgba(34,197,94,.08)}
.choice-btn.correct .choice-label{border-color:var(--green);background:var(--green);color:#fff}
.choice-btn.wrong{border-color:var(--red);background:rgba(239,68,68,.06)}
.choice-btn.wrong .choice-label{border-color:var(--red);background:var(--red);color:#fff}
.choice-btn.disabled{cursor:default;opacity:.85}
.choice-btn.disabled:hover{border-color:var(--border);background:var(--surface)}
.choice-btn.show-correct{border-color:var(--green);background:rgba(34,197,94,.05)}
.choice-btn.show-correct .choice-label{border-color:var(--green);color:var(--green)}

/* Explanation */
.explanation{margin-top:1.2rem;padding:1.1rem;border-radius:10px;background:var(--surface);border-left:3px solid var(--accent);animation:fadeIn .3s ease}
.exp-header{font-weight:700;margin-bottom:.5rem;font-size:.92rem}
.exp-header.correct-h{color:var(--green)}
.exp-header.wrong-h{color:var(--red)}
.exp-body{font-size:.88rem;line-height:1.7;color:var(--text2)}
@keyframes fadeIn{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}

/* Buttons */
.q-actions{margin-top:1rem;display:flex;justify-content:flex-end}
.btn{background:var(--accent);color:#fff;border:none;border-radius:8px;padding:.65rem 1.5rem;font-size:.9rem;font-weight:600;cursor:pointer;transition:all .15s}
.btn:hover{background:var(--accent2);transform:translateY(-1px)}
.btn-outline{background:transparent;border:1.5px solid var(--border);color:var(--text2)}
.btn-outline:hover{border-color:var(--accent);color:var(--accent);background:transparent}
.quiz-nav{text-align:center}

/* ===== Result ===== */
#result-screen{max-width:500px;margin:0 auto;padding:3rem 1rem}
.result-card{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:2.5rem 1.5rem;text-align:center}
.result-icon{font-size:3rem;margin-bottom:.5rem}
.result-card h2{color:var(--text);font-size:1.3rem;margin-bottom:1rem}
.result-score{font-size:2.5rem;font-weight:800;color:var(--accent);margin-bottom:.3rem}
.result-score #result-correct{color:var(--green)}
.result-pct{font-size:1.1rem;color:var(--text2);margin-bottom:1rem}
.result-bar{height:8px;background:var(--border);border-radius:8px;overflow:hidden;margin-bottom:1.5rem}
.result-bar-fill{height:100%;border-radius:8px;transition:width .6s ease}
.result-actions{display:flex;gap:.75rem;justify-content:center;flex-wrap:wrap}

/* ===== Responsive ===== */
@media(max-width:600px){
  .hero h1{font-size:1.5rem}
  .mode-cards{grid-template-columns:repeat(2,1fr)}
  .cat-grid,.year-grid{grid-template-columns:1fr}
  .quiz-card{padding:1.1rem 1rem}
  .q-text{font-size:.95rem}
}