:root {
  --bg: #0e1117;
  --bg-soft: #161b22;
  --bg-card: #1b2230;
  --border: #2a3342;
  --text: #e6edf3;
  --text-dim: #9aa7b8;
  --accent: #ff9900;        /* AWS orange */
  --accent-2: #4f9cf9;
  --ok: #3fb950;
  --ng: #f85149;
  --radius: 14px;
  --shadow: 0 8px 24px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: radial-gradient(1200px 600px at 50% -10%, #1b2536 0%, var(--bg) 55%);
  color: var(--text);
  font-family: "Pretendard", -apple-system, BlinkMacSystemFont, "Segoe UI",
               "Noto Sans KR", "Malgun Gothic", sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--accent-2); }

.wrap {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px 80px;
}

/* ---------- header ---------- */
header {
  border-bottom: 1px solid var(--border);
  background: rgba(14, 17, 23, .8);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo {
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -.3px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo .mark {
  width: 28px; height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), #ff5f6d);
  display: grid; place-items: center;
  font-size: 15px;
}

.logo small {
  display: block;
  font-size: 11px;
  font-weight: 500;
  color: var(--text-dim);
  letter-spacing: 0;
}

.nav { margin-left: auto; display: flex; gap: 6px; }

.nav button {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-dim);
  padding: 7px 13px;
  border-radius: 999px;
  font-size: 13px;
  cursor: pointer;
  font-family: inherit;
}
.nav button:hover { color: var(--text); background: var(--bg-soft); }
.nav button.active { color: var(--text); border-color: var(--border); background: var(--bg-card); }

.demo-badge {
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--accent);
  color: var(--accent);
}

/* ---------- common ---------- */
.hero { padding: 44px 0 28px; }
.hero h1 { font-size: 30px; margin: 0 0 10px; letter-spacing: -.6px; }
.hero p { color: var(--text-dim); margin: 0; }

h2.section { font-size: 15px; color: var(--text-dim); font-weight: 600; margin: 34px 0 14px;
  text-transform: uppercase; letter-spacing: .5px; }

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.grid { display: grid; gap: 14px; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }

button.btn {
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  border-radius: 10px;
  padding: 11px 18px;
  cursor: pointer;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  transition: .12s;
}
button.btn:hover:not(:disabled) { border-color: #3d4a5e; }
button.btn.primary {
  background: linear-gradient(135deg, var(--accent), #ff7a18);
  border-color: transparent;
  color: #1a1206;
}
button.btn.primary:hover:not(:disabled) { filter: brightness(1.08); }
button.btn:disabled { opacity: .4; cursor: not-allowed; }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; }

/* ---------- exam cards ---------- */
.exam-card {
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: .15s;
}
.exam-card:hover { transform: translateY(-2px); border-color: #3d4a5e; box-shadow: var(--shadow); }
.exam-card .code {
  font-size: 12px; font-weight: 700; letter-spacing: .5px;
  color: var(--accent); margin-bottom: 4px;
}
.exam-card h3 { margin: 0 0 6px; font-size: 19px; letter-spacing: -.3px; }
.exam-card p { margin: 0 0 14px; color: var(--text-dim); font-size: 13.5px; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip {
  font-size: 11.5px; padding: 3px 9px; border-radius: 999px;
  background: var(--bg-soft); border: 1px solid var(--border); color: var(--text-dim);
}

.meter { height: 6px; border-radius: 999px; background: var(--bg-soft); overflow: hidden; margin: 12px 0 6px; }
.meter > i { display: block; height: 100%; background: linear-gradient(90deg, var(--accent-2), var(--ok)); }

/* ---------- setup ---------- */
.opt-group { margin-bottom: 18px; }
.opt-group > label.title { font-size: 13px; color: var(--text-dim); display: block; margin-bottom: 8px; }
.seg { display: flex; flex-wrap: wrap; gap: 8px; }
.seg button {
  font-family: inherit; font-size: 13px; cursor: pointer;
  padding: 8px 14px; border-radius: 999px;
  border: 1px solid var(--border); background: var(--bg-soft); color: var(--text-dim);
}
.seg button.on { border-color: var(--accent); color: var(--accent); background: rgba(255,153,0,.08); }

/* ---------- quiz ---------- */
.progress-bar { height: 4px; background: var(--bg-soft); border-radius: 999px; overflow: hidden; }
.progress-bar > i { display: block; height: 100%; background: var(--accent); transition: width .2s; }
.quiz-meta { display: flex; align-items: center; gap: 12px; font-size: 13px; color: var(--text-dim); margin: 26px 0 10px; }
.quiz-meta .spacer { margin-left: auto; }

.q-text { font-size: 18px; font-weight: 600; line-height: 1.55; margin: 6px 0 18px; letter-spacing: -.2px; }

.choices { display: grid; gap: 10px; }
.choice {
  display: flex; gap: 12px; align-items: flex-start;
  text-align: left; width: 100%;
  font-family: inherit; font-size: 14.5px; line-height: 1.5;
  background: var(--bg-soft); color: var(--text);
  border: 1px solid var(--border); border-radius: 12px;
  padding: 13px 15px; cursor: pointer; transition: .12s;
}
.choice:hover:not(:disabled) { border-color: #46566e; }
.choice .key {
  flex: 0 0 24px; height: 24px; border-radius: 7px;
  background: var(--bg-card); border: 1px solid var(--border);
  display: grid; place-items: center; font-size: 12px; font-weight: 700; color: var(--text-dim);
}
.choice.sel { border-color: var(--accent-2); background: rgba(79,156,249,.08); }
.choice.sel .key { border-color: var(--accent-2); color: var(--accent-2); }
.choice.correct { border-color: var(--ok); background: rgba(63,185,80,.1); }
.choice.correct .key { border-color: var(--ok); color: var(--ok); }
.choice.wrong { border-color: var(--ng); background: rgba(248,81,73,.1); }
.choice.wrong .key { border-color: var(--ng); color: var(--ng); }
.choice:disabled { cursor: default; }

.explain {
  margin-top: 16px; padding: 14px 16px; border-radius: 12px;
  background: var(--bg-soft); border: 1px solid var(--border);
  border-left: 3px solid var(--accent-2);
  font-size: 14px; color: #cfd9e5;
}
.explain b { color: var(--text); }

.verdict { font-weight: 700; font-size: 14px; }
.verdict.ok { color: var(--ok); }
.verdict.ng { color: var(--ng); }

/* ---------- result ---------- */
.score-ring {
  display: grid; place-items: center; gap: 2px;
  width: 150px; height: 150px; border-radius: 50%;
  margin: 0 auto 18px;
  background: conic-gradient(var(--accent) var(--pct), var(--bg-soft) 0);
  position: relative;
}
.score-ring::after {
  content: ''; position: absolute; inset: 11px;
  background: var(--bg-card); border-radius: 50%;
}
.score-ring > div { position: relative; z-index: 1; text-align: center; }
.score-ring .big { font-size: 34px; font-weight: 800; line-height: 1.1; }
.score-ring .sub { font-size: 12px; color: var(--text-dim); }

.stat { text-align: center; padding: 16px 10px; }
.stat .v { font-size: 24px; font-weight: 800; letter-spacing: -.5px; }
.stat .k { font-size: 12px; color: var(--text-dim); }

.dom-row { display: flex; align-items: center; gap: 12px; font-size: 13.5px; margin-bottom: 10px; }
.dom-row .name { flex: 0 0 132px; color: var(--text-dim); }
.dom-row .bar { flex: 1; height: 8px; border-radius: 999px; background: var(--bg-soft); overflow: hidden; }
.dom-row .bar > i { display: block; height: 100%; }
.dom-row .num { flex: 0 0 56px; text-align: right; color: var(--text-dim); font-variant-numeric: tabular-nums; }

.review-item { border-top: 1px solid var(--border); padding: 16px 0; }
.review-item:first-child { border-top: 0; padding-top: 0; }
.review-item .qq { font-weight: 600; margin-bottom: 8px; }
.review-item .line { font-size: 13.5px; margin: 3px 0; }
.review-item .line .lbl { color: var(--text-dim); display: inline-block; min-width: 62px; }

.empty { text-align: center; color: var(--text-dim); padding: 40px 20px; }

footer { text-align: center; color: #5d6b7e; font-size: 12px; padding: 30px 0 10px; }

@media (max-width: 560px) {
  .hero h1 { font-size: 24px; }
  .q-text { font-size: 16.5px; }
  .dom-row .name { flex-basis: 96px; font-size: 12px; }
}