:root {
  --ink: #15212b;
  --ink-soft: #5b6b78;
  --paper: #f5f7f6;
  --card: #ffffff;
  --line: #dfe6e3;
  --accent: #0e7d6b;       /* 신뢰감 있는 청록 */
  --accent-soft: #e3f2ee;
  --correct: #0e7d6b;
  --wrong: #c0392b;
  --wrong-soft: #fbeae8;
  --gold: #b98a17;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: "Pretendard", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
}
.hidden { display: none !important; }
.muted { color: var(--ink-soft); font-size: 0.92rem; }

/* ── 상단바 ── */
.topbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; flex-wrap: wrap;
  padding: 14px 24px;
  background: var(--card);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 10;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-mark {
  display: inline-grid; place-items: center;
  width: 38px; height: 38px; border-radius: 10px;
  background: var(--accent); color: #fff;
  font-weight: 800; font-size: 1.2rem;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; }
.nav-btn {
  border: none; background: transparent; cursor: pointer;
  padding: 8px 14px; border-radius: 8px;
  font-size: 0.95rem; color: var(--ink-soft); font-weight: 600;
}
.nav-btn.active { background: var(--accent-soft); color: var(--accent); }
.nav-btn:focus-visible { outline: 2px solid var(--accent); }

main { max-width: 760px; margin: 0 auto; padding: 28px 20px 60px; }
.view-head { display: flex; align-items: center; gap: 12px; }
h1 { font-size: 1.5rem; margin: 0 0 8px; }
h2 { font-size: 1.3rem; margin: 0; }
h3 { font-size: 1.05rem; margin: 24px 0 10px; }

.pill {
  font-size: 0.8rem; font-weight: 700;
  background: var(--accent-soft); color: var(--accent);
  padding: 3px 10px; border-radius: 999px;
}
.pill-gray { background: #eceff1; color: var(--ink-soft); }

/* ── 인증 카드 ── */
.auth-card {
  max-width: 420px; margin: 40px auto;
  background: var(--card); border: 1px solid var(--line);
  border-radius: 16px; padding: 32px 28px;
}
.tab-row { display: flex; gap: 4px; margin: 20px 0 16px; background: var(--paper); border-radius: 10px; padding: 4px; }
.tab { flex: 1; border: none; background: transparent; padding: 8px; border-radius: 8px; cursor: pointer; font-weight: 600; color: var(--ink-soft); }
.tab.active { background: var(--card); color: var(--ink); box-shadow: 0 1px 3px rgba(0,0,0,0.08); }

.auth-form { display: flex; flex-direction: column; gap: 12px; }
.auth-form label { display: flex; flex-direction: column; gap: 4px; font-size: 0.88rem; font-weight: 600; color: var(--ink-soft); }
input, select {
  font: inherit; padding: 10px 12px;
  border: 1px solid var(--line); border-radius: 8px;
  background: #fff;
}
input:focus, select:focus { outline: 2px solid var(--accent); border-color: transparent; }

button { font: inherit; cursor: pointer; }
button.primary {
  background: var(--accent); color: #fff; border: none;
  padding: 11px 18px; border-radius: 8px; font-weight: 700;
}
button.primary:hover { filter: brightness(1.05); }
button.danger { background: #fff; color: var(--wrong); border: 1px solid var(--wrong); padding: 9px 16px; border-radius: 8px; margin-top: 16px; }
.inline-form { display: flex; gap: 8px; }
.inline-form input { flex: 1; }
.inline-form button, .auth-form button:not(.primary) {
  background: var(--ink); color: #fff; border: none; padding: 9px 16px; border-radius: 8px; font-weight: 600;
}

.msg { min-height: 1.2em; font-size: 0.88rem; color: var(--wrong); }
.msg.ok { color: var(--correct); }

/* ── 문제 카드 ── */
.q-card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: 14px; padding: 20px 22px; margin: 16px 0;
}
.q-meta { display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px; }
.q-num { font-weight: 800; color: var(--accent); }
.q-cat { font-size: 0.78rem; color: var(--ink-soft); background: var(--paper); padding: 2px 8px; border-radius: 6px; }
.q-stem { font-weight: 600; white-space: pre-wrap; margin-bottom: 14px; }

.opt {
  display: flex; gap: 10px; align-items: flex-start;
  width: 100%; text-align: left;
  background: #fff; border: 1px solid var(--line); border-radius: 10px;
  padding: 10px 14px; margin: 6px 0; cursor: pointer;
}
.opt:hover { border-color: var(--accent); }
.opt .opt-no { font-weight: 700; color: var(--ink-soft); flex-shrink: 0; }
.opt.selected { border-color: var(--accent); background: var(--accent-soft); }
.opt.correct { border-color: var(--correct); background: var(--accent-soft); }
.opt.wrong { border-color: var(--wrong); background: var(--wrong-soft); }
.opt:disabled { cursor: default; }

.q-actions { margin-top: 12px; }
.result-badge { font-weight: 800; margin: 10px 0 4px; }
.result-badge.ok { color: var(--correct); }
.result-badge.no { color: var(--wrong); }
.explanation {
  background: var(--paper); border-left: 4px solid var(--accent);
  border-radius: 0 10px 10px 0;
  padding: 12px 16px; margin-top: 10px;
  font-size: 0.95rem; white-space: pre-wrap;
}
.explanation strong { color: var(--accent); }

.practice-controls { display: flex; gap: 10px; margin: 14px 0 4px; flex-wrap: wrap; }
.practice-controls select { min-width: 220px; }

/* ── 랭킹 ── */
.rank-table { width: 100%; border-collapse: collapse; background: var(--card); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.rank-table th, .rank-table td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--line); font-size: 0.94rem; }
.rank-table th { background: var(--paper); color: var(--ink-soft); font-size: 0.82rem; }
.rank-table tr:last-child td { border-bottom: none; }
.rank-1 .rank-no { color: var(--gold); font-weight: 800; }
.rank-no { font-weight: 700; }
.empty { padding: 24px; text-align: center; color: var(--ink-soft); background: var(--card); border: 1px dashed var(--line); border-radius: 12px; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 18px 20px; margin: 14px 0; }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 12px; margin-top: 10px; }
.stat { background: var(--paper); border-radius: 10px; padding: 12px; text-align: center; }
.stat b { display: block; font-size: 1.3rem; color: var(--accent); }
.stat span { font-size: 0.8rem; color: var(--ink-soft); }

.foot { text-align: center; padding: 20px; font-size: 0.8rem; }
.spinner { text-align: center; padding: 28px; color: var(--ink-soft); }

/* 랭킹 표가 좁은 화면에서 잘리지 않도록 가로 스크롤 허용 */
#ranking-daily, #ranking-monthly { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.rank-table { min-width: 420px; }

/* ── 모바일 뷰 ── */
@media (max-width: 700px) {
  .topbar { padding: 10px 12px; flex-direction: column; align-items: stretch; gap: 8px; }
  .brand-mark { width: 32px; height: 32px; font-size: 1rem; }
  /* 탭 내비게이션: 한 줄 유지 + 가로 스크롤, 엄지로 누르기 쉬운 크기 */
  .nav { flex-wrap: nowrap; overflow-x: auto; -webkit-overflow-scrolling: touch; scrollbar-width: none; }
  .nav::-webkit-scrollbar { display: none; }
  .nav-btn { flex: 1 0 auto; min-height: 44px; padding: 10px 14px; white-space: nowrap; }

  main { padding: 18px 12px 60px; }
  .auth-card { padding: 24px 18px; margin: 16px auto; }

  /* iOS에서 입력란 포커스 시 화면 자동 확대 방지(16px 이상이면 확대 안 함) */
  input, select, button { font-size: 16px; }

  /* 터치 타깃 최소 44px 확보 */
  .opt { min-height: 48px; padding: 12px 14px; }
  button.primary, .btn-submit, #btn-new-practice { min-height: 46px; width: 100%; }
  .practice-controls { flex-direction: column; }
  .practice-controls select { width: 100%; min-width: 0; }
  .inline-form { flex-direction: column; }
  .inline-form button { min-height: 44px; }

  .q-card { padding: 16px 14px; border-radius: 12px; }
  .q-stem { font-size: 0.98rem; }
  .stat-grid { grid-template-columns: repeat(3, 1fr); gap: 8px; }
  .stat b { font-size: 1.1rem; }
  .rank-table th, .rank-table td { padding: 9px 10px; font-size: 0.88rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}