* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #f3f5f9;
  --card: #ffffff;
  --primary: #4f6ef7;
  --primary-dark: #3a56d4;
  --green: #2f9e5c;
  --red: #e5533d;
  --text: #1f2430;
  --dim: #7a8299;
  --border: #e3e7f0;
  --radius: 14px;
}

body {
  font-family: "Segoe UI", "Noto Sans Thai", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container { max-width: 960px; margin: 0 auto; padding: 0 20px; width: 100%; }

/* topbar */
.topbar { background: #fff; border-bottom: 1px solid var(--border); }
.topbar-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { font-weight: 800; font-size: 20px; text-decoration: none; color: var(--text); }
.nav a { margin-left: 18px; text-decoration: none; color: var(--primary); font-weight: 600; }

/* main */
main { flex: 1; padding: 28px 0 40px; }
.footer { border-top: 1px solid var(--border); padding: 18px 0; color: var(--dim); font-size: 13px; text-align: center; background: #fff; }

/* hero */
.hero { text-align: center; padding: 40px 0 24px; }
.hero h1 { font-size: 40px; }
.subtitle { color: var(--dim); font-size: 17px; line-height: 1.6; margin: 12px 0 22px; }
.hero-actions { display: flex; justify-content: center; gap: 12px; }

/* cards */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: 0 1px 3px rgba(20, 30, 60, .05);
}

.howto-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 14px; }
.howto .card { line-height: 1.7; }
.dim { color: var(--dim); font-size: 14px; }

.section { margin-top: 34px; }
.section h2 { margin-bottom: 14px; }

/* buttons */
.btn {
  display: inline-block;
  padding: 11px 22px;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  text-decoration: none;
  color: var(--text);
  transition: all .15s;
}
.btn:hover { background: #f0f2f8; }
.btn-primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-danger { background: #fdecec; border-color: #f5c6c6; color: var(--red); }
.btn-block { display: block; width: 100%; text-align: center; }

/* quiz list */
.quiz-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(270px, 1fr)); gap: 14px; }
.quiz-card h3 { margin-bottom: 6px; }
.quiz-card p { color: var(--dim); font-size: 14px; min-height: 40px; }
.quiz-card .meta { margin: 10px 0; font-size: 13px; color: var(--dim); }
.quiz-card .btn { width: 100%; text-align: center; }

/* leaderboard */
.leaderboard { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.lb-row { display: grid; grid-template-columns: 40px 1fr 1fr 70px; gap: 10px; padding: 12px 18px; align-items: center; border-bottom: 1px solid var(--border); }
.lb-row:last-child { border-bottom: none; }
.lb-row.head { background: #f7f9ff; font-weight: 700; color: var(--dim); font-size: 13px; }
.lb-rank { font-weight: 800; }
.lb-empty { padding: 30px; text-align: center; color: var(--dim); }

/* game */
.hud { display: flex; justify-content: space-between; align-items: center; background: #fff; border: 1px solid var(--border); border-radius: 12px; padding: 12px 18px; margin-bottom: 20px; }
.hud-left, .hud-right { display: flex; align-items: center; gap: 14px; }
.badge { background: var(--primary); color: #fff; border-radius: 20px; padding: 4px 14px; font-weight: 700; font-size: 13px; }

.question-area { text-align: center; background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 30px 24px; }
.instruction {
  display: inline-block;
  background: #eef1ff;
  color: #3a56d4;
  font-weight: 700;
  border-radius: 20px;
  padding: 8px 18px;
  margin-bottom: 18px;
  font-size: 15px;
}
.question-area h2 { font-size: 28px; margin-bottom: 16px; word-break: break-word; }
.q-image { max-width: 420px; margin: 0 auto 16px; }
.q-image img { width: 100%; border-radius: 10px; }

.options { display: flex; flex-direction: column; gap: 12px; max-width: 520px; margin: 0 auto; }
.option {
  background: #fff;
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  font-size: 17px;
  cursor: pointer;
  text-align: left;
  transition: all .15s;
}
.option:hover { border-color: var(--primary); background: #f4f6ff; }
.option.correct { border-color: var(--green); background: #eaf7f0; font-weight: 700; }
.option.wrong { border-color: var(--red); background: #fdefec; }
.option:disabled { cursor: default; }

/* feedback */
.feedback { position: fixed; inset: 0; background: rgba(20, 30, 60, .55); display: flex; align-items: center; justify-content: center; z-index: 20; padding: 20px; }
.fb-card { max-width: 480px; width: 100%; text-align: center; }
.fb-card h2 { margin: 8px 0; }
.fb-card p { color: var(--dim); margin-bottom: 10px; }
.li-text { white-space: pre-line; line-height: 1.8; text-align: left; padding: 6px 12px; }
#fb-icon { font-size: 52px; }
#fb-image-wrap { margin: 12px auto; max-width: 380px; }
#fb-image { width: 100%; border-radius: 10px; }
.feedback .btn { margin-top: 8px; }

/* result */
.result { text-align: center; }
.result-card { max-width: 480px; margin: 30px auto; }
.stars { font-size: 44px; letter-spacing: 8px; margin: 12px 0; }
.result-actions { display: flex; gap: 10px; justify-content: center; margin-top: 18px; }

/* review */
.review { max-width: 720px; margin: 10px auto 60px; text-align: left; }
.review h3 { margin: 24px 0 10px; }
.review .rv-note { color: var(--dim); margin-bottom: 8px; }
.review-list { display: flex; flex-direction: column; gap: 10px; }
.rv-item { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; }
.rv-item .rv-word { font-weight: 800; font-size: 18px; color: var(--primary); }
.rv-item .rv-th { font-weight: 700; color: var(--green); margin-left: 8px; }
.rv-item .rv-meaning { color: var(--dim); margin-top: 4px; font-size: 14px; }
.rv-item .rv-sentence { margin-top: 4px; font-style: italic; color: #444; font-size: 14px; }
.rv-item .rv-tags { margin-top: 6px; }
.rv-tag { display: inline-block; font-size: 12px; padding: 2px 8px; border-radius: 999px; background: #eef1ff; color: var(--primary); margin-right: 6px; }

.hidden { display: none !important; }
.row-between { display: flex; align-items: center; justify-content: space-between; gap: 12px; }

/* match game */
.m-instruction { display: block; background: #eef1ff; color: #3a56d4; font-weight: 700; border-radius: 14px; padding: 12px 18px; margin-bottom: 18px; font-size: 14px; line-height: 1.7; text-align: center; }
.m-board { position: relative; display: flex; gap: 10px; background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; }
.m-col { display: flex; flex-direction: column; gap: 14px; flex: 1; }
.m-lines { position: absolute; top: 0; left: 0; pointer-events: none; z-index: 1; }
.m-line { stroke: #9db1ff; stroke-width: 3; }
.m-line.ok { stroke: var(--green); stroke-width: 4; }
.m-line.bad { stroke: var(--red); stroke-width: 4; }
.m-item {
  background: #fff;
  border: 2px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  font-size: 15px;
  cursor: pointer;
  line-height: 1.4;
  transition: all .12s;
  position: relative;
  z-index: 2;
}
.m-item:hover { border-color: var(--primary); background: #f4f6ff; }
.m-left-item { text-align: right; font-weight: 700; }
.m-left-item.selected { border-color: var(--primary); background: #e4eaff; box-shadow: 0 0 0 3px rgba(79,110,247,.2); }
.m-right-item { text-align: left; display: flex; align-items: center; gap: 10px; }
.m-text { flex: 1; }
.m-tag {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 24px;
  height: 24px;
  border-radius: 50%;
  background: #fff;
  border: 2px solid var(--primary);
  color: var(--primary);
  font-weight: 800;
  font-size: 13px;
  visibility: hidden;
}
.m-item.linked { border-color: var(--green); background: #d9f4e3; }
.m-right-item.linked .m-tag { visibility: visible; background: var(--green); border-color: var(--green); color: #fff; }
.m-item.ok { border-color: var(--green); background: #eaf7f0; font-weight: 700; }
.m-item.bad { border-color: var(--red); background: #fdefec; }

.candidate-list { margin-top: 10px; display: flex; flex-direction: column; gap: 6px; }
.candidate-item { background: #fff; border: 1px solid var(--border); border-radius: 10px; padding: 8px 12px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.candidate-item .check { font-size: 15px; }
.candidate-item .dim { font-size: 13px; }
.candidate-list .btn { margin-top: 8px; }

/* auth */
.auth-card { max-width: 400px; margin: 50px auto; background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 30px; }
.auth-card h2 { margin-bottom: 16px; }
.auth-card label { display: block; font-weight: 700; margin: 12px 0 6px; font-size: 14px; }
.auth-card input { width: 100%; padding: 12px; border: 1px solid var(--border); border-radius: 10px; font-size: 15px; }
.auth-card .btn { margin-top: 18px; }
.auth-link { text-align: center; margin-top: 16px; color: var(--dim); }
.error { color: var(--red); font-size: 14px; margin-top: 10px; min-height: 18px; }

/* admin */
.admin-layout { display: grid; grid-template-columns: 240px 1fr; gap: 20px; }
.quiz-nav { display: flex; flex-direction: column; gap: 8px; margin-top: 14px; }
.quiz-nav-item { padding: 12px; border: 1px solid var(--border); border-radius: 10px; cursor: pointer; background: #fff; }
.quiz-nav-item.active { border-color: var(--primary); background: #f4f6ff; }
.quiz-nav-item b { display: block; }
.quiz-nav-item span { font-size: 12px; color: var(--dim); }

.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 20px; }
.form-grid .span-2 { grid-column: span 2; }
.form-grid label { display: block; font-size: 13px; font-weight: 700; margin-bottom: 4px; }
.form-grid input, .form-grid textarea, .form-grid select { width: 100%; padding: 10px; border: 1px solid var(--border); border-radius: 8px; font-size: 14px; }

.word-row { display: grid; grid-template-columns: 1fr 2fr 2fr auto auto; gap: 8px; align-items: center; padding: 10px 0; border-bottom: 1px solid var(--border); font-size: 14px; }
.word-row.head { color: var(--dim); font-weight: 700; font-size: 12px; border-bottom: 2px solid var(--border); }
.word-row .thumb { width: 56px; height: 40px; object-fit: cover; border-radius: 6px; border: 1px solid var(--border); }
.icon-btn { background: none; border: none; cursor: pointer; font-size: 16px; }

.file-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; margin-top: 16px; }
.file-item { border: 1px solid var(--border); border-radius: 10px; padding: 10px; text-align: center; }
.file-item img { width: 100%; height: 90px; object-fit: cover; border-radius: 8px; margin-bottom: 6px; }
.file-item .fname { font-size: 11px; color: var(--dim); word-break: break-all; }
.file-item .copy { font-size: 12px; margin-top: 4px; }

#upload-panel, #quiz-panel { margin-bottom: 20px; }
code { background: #f0f2f8; padding: 2px 6px; border-radius: 6px; font-size: 13px; }

@media (max-width: 720px) {
  .admin-layout { grid-template-columns: 1fr; }
  .form-grid { grid-template-columns: 1fr; }
  .form-grid .span-2 { grid-column: span 1; }
  .word-row { grid-template-columns: 1fr; gap: 4px; }
  .lb-row { grid-template-columns: 30px 1fr 1fr 60px; }
  .hero h1 { font-size: 30px; }
  .m-board { padding: 10px; gap: 6px; }
  .m-col { gap: 8px; }
  .m-item { padding: 7px 8px; font-size: 13px; }
  .m-tag { min-width: 20px; height: 20px; font-size: 11px; }
  .m-instruction { font-size: 12px; padding: 10px 12px; }
}