:root {
  color-scheme: dark;
  --ink: #eef8ff;
  --muted: #9db5cd;
  --navy: #071a33;
  --panel: rgba(12, 37, 67, .92);
  --panel-2: #102d50;
  --cyan: #5ee6d0;
  --yellow: #ffd166;
  --coral: #ff7f66;
  --orange: #f2a65a;
  --line: rgba(157, 190, 219, .18);
  --shadow: 0 22px 70px rgba(0, 10, 26, .42);
  font-family: "Pretendard", "Noto Sans KR", system-ui, sans-serif;
}
* { box-sizing: border-box; }
html { min-height: 100%; background: var(--navy); }
body { margin: 0; min-height: 100vh; color: var(--ink); background: radial-gradient(circle at 80% 0%, #173e64 0, transparent 35%), linear-gradient(155deg, #06172e, #0b2946 60%, #071a33); }
button, input, select { font: inherit; }
button { cursor: pointer; }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 3px solid var(--yellow); outline-offset: 3px; }
.sky-glow { position: fixed; inset: 0; pointer-events: none; opacity: .3; background-image: radial-gradient(#fff 1px, transparent 1px); background-size: 44px 44px; mask-image: linear-gradient(to bottom, #000, transparent 65%); }
#app { position: relative; z-index: 1; min-height: 100vh; }
.shell { width: min(1180px, calc(100% - 32px)); margin: 0 auto; padding: 20px 0 44px; }
.topbar { min-height: 64px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: flex; align-items: center; gap: 12px; color: white; font-weight: 900; letter-spacing: -.02em; }
.brand-mark { width: 40px; height: 40px; display: grid; place-items: center; border-radius: 13px; background: var(--cyan); color: var(--navy); box-shadow: 0 8px 22px rgba(94,230,208,.25); }
.utility { display: flex; align-items: center; gap: 8px; }
.icon-btn, .ghost-btn { border: 1px solid var(--line); background: rgba(255,255,255,.06); color: var(--ink); border-radius: 12px; min-height: 44px; padding: 0 14px; }
.icon-btn { width: 44px; padding: 0; }
.screen { animation: rise .35s ease both; }
@keyframes rise { from { opacity: 0; transform: translateY(8px); } }
.login-wrap { min-height: calc(100vh - 90px); display: grid; grid-template-columns: 1.1fr .9fr; align-items: center; gap: 36px; }
.intro h1 { margin: 0; max-width: 720px; font-size: clamp(3rem, 7vw, 6.7rem); line-height: .94; letter-spacing: -.075em; }
.intro h1 span { display: block; color: var(--cyan); }
.intro p { font-size: 1.1rem; line-height: 1.8; color: var(--muted); max-width: 560px; margin: 24px 0; }
.track-mini { position: relative; margin-top: 24px; height: 190px; border-bottom: 5px dashed rgba(255,255,255,.18); overflow: hidden; }
.character-lineup { width: 100%; height: 100%; object-fit: contain; object-position: center bottom; filter: drop-shadow(0 14px 12px rgba(0,0,0,.26)); }
.track-mini .runner { position: absolute; bottom: 10px; font-size: 3.6rem; filter: drop-shadow(0 8px 8px rgba(0,0,0,.25)); animation: jog 1.2s ease-in-out infinite alternate; }
.track-mini .runner:nth-child(1) { left: 8%; }
.track-mini .runner:nth-child(2) { left: 30%; animation-delay: -.3s; }
.track-mini .runner:nth-child(3) { left: 52%; animation-delay: -.6s; }
.track-mini .runner:nth-child(4) { left: 74%; animation-delay: -.9s; }
@keyframes jog { to { transform: translateY(-7px) rotate(-3deg); } }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 28px; box-shadow: var(--shadow); }
.login-card { padding: clamp(24px, 5vw, 44px); }
.login-card h2 { margin: 0 0 8px; font-size: 1.75rem; }
.login-card > p { margin: 0 0 24px; color: var(--muted); line-height: 1.6; }
.role-tabs { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; padding: 5px; background: rgba(0,0,0,.18); border-radius: 14px; margin-bottom: 22px; }
.role-tabs button { min-height: 44px; border: 0; border-radius: 10px; background: transparent; color: var(--muted); font-weight: 800; }
.role-tabs button.active { color: var(--navy); background: var(--cyan); }
.field { display: grid; gap: 8px; margin: 16px 0; }
.field label { font-size: .95rem; font-weight: 750; }
.field input, .field select { width: 100%; min-height: 54px; border: 1px solid var(--line); border-radius: 14px; background: #081f3a; color: white; padding: 0 16px; font-size: 1rem; }
.primary-btn { width: 100%; min-height: 58px; border: 0; border-radius: 16px; background: var(--yellow); color: #10243a; font-weight: 950; box-shadow: 0 9px 0 #c78f22; margin-top: 12px; transition: .15s; }
.primary-btn:hover { transform: translateY(-2px); box-shadow: 0 11px 0 #c78f22; }
.primary-btn:active { transform: translateY(4px); box-shadow: 0 5px 0 #c78f22; }
.hint { color: var(--muted); font-size: .85rem; margin-top: 14px; line-height: 1.5; }
.connection-status { display: inline-flex; align-items: center; gap: 8px; margin-top: 14px; color: var(--muted); font-size: .85rem; }
.connection-status::before { content: ""; width: 9px; height: 9px; border-radius: 50%; background: var(--orange); box-shadow: 0 0 0 4px rgba(242,166,90,.12); }
.connection-status.connected::before { background: var(--cyan); box-shadow: 0 0 0 4px rgba(94,230,208,.12); }
.setup-list { display: grid; gap: 10px; margin: 14px 0 0; padding: 0; list-style: none; }
.setup-list li { display: grid; grid-template-columns: 26px 1fr; gap: 8px; align-items: start; color: var(--muted); line-height: 1.5; }
.setup-list b { color: var(--ink); }
.home-head { display: flex; justify-content: space-between; align-items: end; margin: 30px 0 20px; gap: 20px; }
.eyebrow { color: var(--cyan); text-transform: uppercase; font-weight: 900; letter-spacing: .12em; font-size: .78rem; }
.home-head h1 { margin: 6px 0 0; font-size: clamp(2rem, 5vw, 4.2rem); letter-spacing: -.055em; line-height: 1; }
.level-pill { white-space: nowrap; padding: 12px 16px; border: 1px solid var(--line); border-radius: 999px; background: rgba(255,255,255,.06); font-weight: 800; }
.mission-strip { display: grid; grid-template-columns: auto 1fr auto; gap: 16px; align-items: center; padding: 18px 20px; border: 1px solid rgba(94,230,208,.28); border-radius: 20px; background: linear-gradient(90deg, rgba(94,230,208,.12), rgba(255,209,102,.05)); }
.mission-icon { width: 50px; height: 50px; display: grid; place-items: center; border-radius: 15px; background: var(--cyan); color: var(--navy); font-size: 1.5rem; }
.mission-strip strong { display: block; font-size: 1.05rem; }
.mission-strip small { color: var(--muted); }
.progress-ring { width: 56px; height: 56px; display: grid; place-items: center; border-radius: 50%; background: conic-gradient(var(--yellow) var(--p), rgba(255,255,255,.09) 0); font-weight: 900; position: relative; }
.progress-ring::after { content: ""; position: absolute; inset: 6px; background: #103052; border-radius: 50%; }
.progress-ring span { position: relative; z-index: 1; font-size: .76rem; }
.home-grid { display: grid; grid-template-columns: 1.35fr .65fr; gap: 18px; margin-top: 18px; }
.modes { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.mode-card { position: relative; overflow: hidden; text-align: left; min-height: 180px; padding: 22px; border: 1px solid var(--line); border-radius: 24px; color: white; background: linear-gradient(145deg, #123b62, #0e2a49); transition: transform .2s, border-color .2s; }
.mode-card:hover { transform: translateY(-4px); border-color: rgba(94,230,208,.7); }
.mode-card.practice { grid-column: span 2; background: linear-gradient(110deg, #0b5b61, #123b62); }
.mode-card .emoji { font-size: 2.4rem; }
.mode-card h3 { margin: 16px 0 6px; font-size: 1.35rem; }
.mode-card p { margin: 0; max-width: 340px; color: #c7dceb; line-height: 1.5; }
.mode-card .arrow { position: absolute; right: 18px; bottom: 16px; width: 42px; height: 42px; display: grid; place-items: center; border-radius: 50%; background: rgba(255,255,255,.1); font-size: 1.2rem; }
.side-stack { display: grid; gap: 14px; }
.panel { padding: 20px; }
.panel h3 { margin: 0 0 14px; }
.mastery-row { display: grid; grid-template-columns: 32px 1fr 42px; gap: 10px; align-items: center; margin: 10px 0; }
.bar { height: 8px; border-radius: 999px; overflow: hidden; background: rgba(255,255,255,.08); }
.bar > i { display: block; height: 100%; background: linear-gradient(90deg, var(--cyan), var(--yellow)); border-radius: inherit; }
.rank-list { display: grid; gap: 10px; }
.rank { display: grid; grid-template-columns: 28px 1fr auto; align-items: center; gap: 10px; color: var(--muted); }
.rank.you { color: var(--ink); background: rgba(94,230,208,.1); margin: 0 -8px; padding: 9px 8px; border-radius: 12px; }
.game-layout { padding-top: 8px; }
.game-hud { display: grid; grid-template-columns: 1fr auto 1fr; gap: 14px; align-items: center; margin: 14px 0; }
.hud-stat { display: flex; gap: 12px; align-items: center; }
.hud-stat.right { justify-content: end; text-align: right; }
.hud-stat strong { display: block; font-size: 1.1rem; }
.hud-stat span { color: var(--muted); font-size: .84rem; }
.timer { min-width: 98px; padding: 12px 16px; border: 1px solid var(--line); border-radius: 16px; background: rgba(0,0,0,.2); text-align: center; font-size: 1.45rem; font-weight: 950; font-variant-numeric: tabular-nums; }
.race-track { position: relative; height: 160px; overflow: hidden; border: 1px solid rgba(255,255,255,.15); border-radius: 25px; background: linear-gradient(#164d65 0 52%, #183d37 52% 56%, #7e5b3a 56%); }
.race-track::before, .race-track::after { content: ""; position: absolute; left: 34px; right: 28px; height: 4px; background: repeating-linear-gradient(90deg, rgba(255,255,255,.35) 0 20px, transparent 20px 40px); }
.race-track::before { top: 78px; } .race-track::after { top: 132px; }
.finish { position: absolute; right: 28px; top: 42px; bottom: 8px; width: 12px; background: repeating-linear-gradient(0deg, white 0 8px, #172740 8px 16px); }
.racer { position: absolute; left: 20px; font-size: 2.8rem; transition: left .55s cubic-bezier(.2,.8,.2,1); filter: drop-shadow(0 8px 6px rgba(0,0,0,.25)); }
.racer.me { top: 48px; } .racer.rival { top: 102px; }
.game-card { width: min(700px, 100%); margin: 18px auto 0; padding: clamp(20px, 5vw, 36px); text-align: center; }
.game-card .label { color: var(--cyan); font-weight: 900; letter-spacing: .08em; }
.question { margin: 14px 0 18px; font-size: clamp(2.5rem, 9vw, 5.8rem); font-weight: 950; letter-spacing: -.04em; font-variant-numeric: tabular-nums; }
.feedback { min-height: 32px; font-weight: 900; font-size: 1.05rem; }
.feedback.good { color: var(--cyan); } .feedback.bad { color: var(--orange); }
.keypad { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; width: min(430px, 100%); margin: 8px auto 0; }
.keypad button { min-height: 60px; border: 1px solid var(--line); border-radius: 16px; background: #153d65; color: white; font-size: 1.3rem; font-weight: 900; box-shadow: 0 4px 0 #06192f; }
.keypad button:hover { background: #1c507f; }
.keypad .submit { background: var(--yellow); color: var(--navy); grid-column: span 2; }
.answer-display { width: min(430px, 100%); min-height: 58px; margin: 0 auto 10px; display: grid; place-items: center; border: 2px solid var(--line); border-radius: 16px; background: #061a32; font-size: 1.7rem; font-weight: 950; }
.answer-display.empty { color: #65819d; }
.result-wrap { width: min(860px, 100%); margin: 36px auto; }
.result-hero { text-align: center; padding: 34px; }
.result-hero .big { font-size: 4rem; }
.result-hero h1 { margin: 8px 0; font-size: clamp(2rem, 6vw, 3.8rem); letter-spacing: -.05em; }
.result-hero p { color: var(--muted); }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin: 16px 0; }
.stat { padding: 18px; text-align: center; }
.stat b { display: block; color: var(--cyan); font-size: 1.6rem; }
.stat span { color: var(--muted); font-size: .84rem; }
.review-list { display: grid; gap: 8px; }
.review-item { display: flex; justify-content: space-between; gap: 10px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.review-item:last-child { border-bottom: 0; }
.actions { display: flex; gap: 10px; margin-top: 18px; }
.actions .primary-btn { margin: 0; }
.teacher-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin: 18px 0; }
.teacher-grid .stat { text-align: left; }
.heatmap { display: grid; grid-template-columns: 120px repeat(8, 1fr); gap: 5px; align-items: center; font-size: .84rem; }
.heat-cell { min-height: 42px; display: grid; place-items: center; border-radius: 9px; background: color-mix(in srgb, var(--coral) calc((100 - var(--score)) * 1%), var(--cyan)); color: #071a33; font-weight: 900; }
.student-row { display: grid; grid-template-columns: 1.2fr .8fr .8fr auto; gap: 12px; align-items: center; padding: 13px 0; border-bottom: 1px solid var(--line); }
.class-settings { margin-top: 14px; }
.class-settings fieldset { margin: 0; padding: 0; border: 0; }
.class-settings legend { margin-bottom: 10px; font-weight: 800; }
.table-checks { display: grid; grid-template-columns: repeat(8, minmax(54px, 1fr)); gap: 8px; }
.table-checks label, .check-line { display: flex; min-height: 44px; align-items: center; justify-content: center; gap: 7px; border: 1px solid var(--line); border-radius: 12px; background: rgba(255,255,255,.04); }
.table-checks input, .check-line input { width: 18px; height: 18px; accent-color: var(--cyan); }
.settings-row { display: grid; grid-template-columns: minmax(180px, 1fr) minmax(220px, 1fr) auto; align-items: end; gap: 12px; margin-top: 16px; }
.settings-row > label:first-child { display: grid; gap: 7px; font-weight: 800; }
.settings-row select { min-height: 44px; border: 1px solid var(--line); border-radius: 12px; background: #081f3a; color: white; padding: 0 12px; }
.teacher-loading { margin-top: 30px; }
dialog { width: min(480px, calc(100% - 24px)); padding: 0; border: 1px solid var(--line); border-radius: 24px; background: #0d2a49; color: var(--ink); box-shadow: var(--shadow); }
dialog::backdrop { background: rgba(0,10,26,.72); backdrop-filter: blur(5px); }
.dialog-card { padding: 24px; }
.dialog-head { display: flex; align-items: start; justify-content: space-between; gap: 14px; }
.dialog-head h2 { margin: 6px 0 8px; }
.dialog-card input[readonly] { opacity: .7; }
#toast { position: fixed; z-index: 20; left: 50%; bottom: 24px; transform: translate(-50%, 20px); opacity: 0; padding: 12px 18px; border-radius: 999px; background: #eef8ff; color: #071a33; font-weight: 800; transition: .2s; pointer-events: none; }
#toast.show { opacity: 1; transform: translate(-50%, 0); }
@media (max-width: 820px) {
  .login-wrap, .home-grid { grid-template-columns: 1fr; }
  .intro { padding-top: 28px; }
  .intro h1 { font-size: clamp(3.2rem, 15vw, 5.5rem); }
  .track-mini { margin-top: 8px; height: 140px; }
  .home-head { align-items: start; flex-direction: column; }
  .teacher-grid, .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .heatmap { grid-template-columns: 82px repeat(8, minmax(34px, 1fr)); overflow-x: auto; }
  .table-checks { grid-template-columns: repeat(4, 1fr); }
  .settings-row { grid-template-columns: 1fr; align-items: stretch; }
}
@media (max-width: 520px) {
  .shell { width: min(100% - 20px, 1180px); padding-top: 10px; }
  .topbar { min-height: 54px; }
  .intro p { font-size: 1rem; margin: 16px 0; }
  .login-card { border-radius: 22px; }
  .mission-strip { grid-template-columns: auto 1fr; }
  .mission-strip .progress-ring { display: none; }
  .modes { grid-template-columns: 1fr; }
  .mode-card.practice { grid-column: auto; }
  .game-hud { grid-template-columns: 1fr 76px 1fr; gap: 6px; }
  .hud-stat { gap: 4px; } .hud-stat .face { display: none; }
  .timer { min-width: 0; padding: 10px 6px; font-size: 1.15rem; }
  .race-track { height: 144px; }
  .racer { font-size: 2.4rem; }
  .game-card { border-radius: 22px; }
  .question { margin-top: 8px; }
  .keypad button { min-height: 56px; }
  .teacher-grid, .stats-grid { grid-template-columns: 1fr 1fr; }
  .student-row { grid-template-columns: 1fr auto; }
  .student-row span:nth-child(2), .student-row span:nth-child(3) { display: none; }
}
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; } }