:root {
  --bg: #1e1e2e;
  --surface: #2a2a3e;
  --border: #44475a;
  --text: #cdd6f4;
  --muted: #6c7086;
  --accent: #89b4fa;
  --green: #a6e3a1;
  --yellow: #f9e2af;
  --red: #f38ba8;
  --blank-bg: #313244;
}

body.light {
  --bg: #f0ede8;
  --surface: #faf8f5;
  --border: #c8c4bc;
  --text: #2c2a27;
  --muted: #8a8680;
  --accent: #3b6fd4;
  --green: #2d7a3a;
  --yellow: #8a6200;
  --red: #c0392b;
  --blank-bg: #e8e4de;
}

* { box-sizing: border-box; margin: 0; padding: 0; max-width: 100%; }

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  padding: 2rem;
  max-width: 1050px;
  margin: 0 auto;
}

@media (max-width: 600px) {
  body { padding: 0.5rem; }
  input.blank { min-width: 0 !important; width: calc(100% - 8px); display: block; margin: 0.3rem 0; }
}

h1 { color: var(--accent); font-size: 1.6rem; margin-bottom: 0.3rem; }
h2 { color: var(--yellow); font-size: 1.2rem; margin: 2rem 0 1rem; border-left: 3px solid var(--yellow); padding-left: 0.7rem; }
h3 { color: var(--green); font-size: 1rem; margin: 1.5rem 0 0.5rem; }

.nav-back { display: inline-block; color: var(--muted); text-decoration: none; margin-bottom: 1.5rem; font-size: 0.9rem; }
.nav-back:hover { color: var(--accent); }

.question {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  margin: 1rem 0;
}

.question-header {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin-bottom: 0.5rem;
}

.q-type {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.type-fill { background: var(--border); color: var(--yellow); }
.type-short { background: var(--border); color: var(--green); }
.type-proof { background: var(--border); color: var(--red); }

.q-text { flex: 1; }

/* blank: inline input for fill-in */
input.blank {
  display: inline-block;
  min-width: 120px;
  border: none;
  border-bottom: 2px solid var(--accent);
  margin: 0 4px;
  vertical-align: bottom;
  height: 1.4em;
  background: var(--blank-bg);
  border-radius: 3px 3px 0 0;
  padding: 0 4px;
  color: var(--text);
  font-size: inherit;
  font-family: inherit;
  outline: none;
}
input.blank:focus { border-bottom-color: var(--green); background: #3a3a54; }

/* write area for short/proof */
.write-area {
  width: 100%;
  min-height: 80px;
  background: var(--blank-bg);
  border: 1px dashed var(--border);
  border-radius: 6px;
  margin-top: 0.6rem;
  padding: 0.5rem;
  color: var(--text);
  font-size: 0.85rem;
  resize: vertical;
}
.write-area.tall { min-height: 160px; }
.write-area.xtall { min-height: 240px; }

/* font size controls */
.font-controls {
  position: fixed;
  bottom: 1.2rem;
  right: 1.2rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.7rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  z-index: 100;
  font-size: 0.78rem;
  color: var(--muted);
}
.font-controls .fc-toggle { cursor: pointer; user-select: none; color: var(--text); }
.font-controls .fc-inner { display: none; align-items: center; gap: 0.5rem; flex-wrap: wrap; max-width: 320px; }
.font-controls.open .fc-inner { display: flex; }
.font-controls label { color: var(--muted); white-space: nowrap; }
.font-controls .fc-sep { width: 100%; border-top: 1px solid var(--border); margin: 0.2rem 0; }
.font-controls .fc-api-open { background: none; border: 1px solid var(--border); border-radius: 4px; color: var(--muted); padding: 0.15rem 0.5rem; cursor: pointer; font-size: 0.78rem; }
.font-controls .fc-api-open:hover { border-color: var(--accent); color: var(--accent); }
.font-controls .fc-clear-page { background: none; border: 1px solid var(--border); border-radius: 4px; color: var(--muted); padding: 0.15rem 0.5rem; cursor: pointer; font-size: 0.78rem; }
.font-controls .fc-clear-page:hover { border-color: var(--red); color: var(--red); }

/* API config modal */
.api-modal { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.5); z-index: 200; align-items: center; justify-content: center; }
.api-modal.open { display: flex; }
.api-modal-box { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 1.2rem 1.5rem; width: min(560px, 92vw); display: flex; flex-direction: column; gap: 0.5rem; }
.api-modal-box h3 { color: var(--accent); font-size: 1rem; margin-bottom: 0.2rem; }
.api-modal-box label { font-size: 0.8rem; color: var(--muted); }
.api-modal-box input:not([type=checkbox]), .api-modal-box select { background: var(--blank-bg); border: 1px solid var(--border); border-radius: 5px; color: var(--text); padding: 0.4rem 0.6rem; font-size: 0.88rem; width: 100%; }
.api-modal-box input:not([type=checkbox]):focus, .api-modal-box select:focus { outline: none; border-color: var(--accent); }
.api-modal-box .clr-option { display: flex; align-items: center; gap: 0.6rem; padding: 0.5rem 0.7rem; border: 1px solid var(--border); border-radius: 6px; cursor: pointer; font-size: 0.88rem; color: var(--text); transition: border-color 0.15s; }
.api-modal-box .clr-option:hover { border-color: var(--accent); }
.api-modal-box .clr-option input { width: auto; background: none; border: none; padding: 0; accent-color: var(--accent); cursor: pointer; }
.api-modal-row { display: flex; align-items: center; gap: 0.6rem; margin-top: 0.3rem; }
.api-modal-row button { background: none; border: 1px solid var(--border); border-radius: 5px; color: var(--muted); padding: 0.3rem 0.8rem; cursor: pointer; font-size: 0.82rem; }
.api-modal-row button:hover { border-color: var(--accent); color: var(--accent); }
.api-modal-row .fc-api-status { font-size: 0.82rem; }
.font-controls .fc-size { min-width: 2.2rem; text-align: center; color: var(--text); }
.font-controls input[type=range] { width: 90px; accent-color: var(--accent); cursor: pointer; }
.font-controls .fc-theme { background: none; border: 1px solid var(--border); border-radius: 4px; cursor: pointer; padding: 0.1rem 0.4rem; font-size: 0.85rem; }
.font-controls .fc-ver { color: var(--muted); font-family: monospace; font-size: 0.72rem; }

/* answer reveal */
.answer-btn {
  margin-top: 0.7rem;
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 0.3rem 0.8rem;
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.82rem;
  transition: all 0.15s;
}
.answer-btn:hover { border-color: var(--accent); color: var(--accent); }

.answer {
  display: none;
  margin-top: 0.7rem;
  padding: 0.7rem 1rem;
  background: var(--blank-bg);
  border-left: 3px solid var(--accent);
  border-radius: 0 6px 6px 0;
  font-size: 0.92rem;
}
.answer.visible { display: block; }

/* AI grading */
.grade-btn {
  margin-top: 0.7rem;
  margin-left: 0.4rem;
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 0.3rem 0.8rem;
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.82rem;
  transition: all 0.15s;
}
.grade-btn:hover { border-color: var(--green); color: var(--green); }
.grade-btn:disabled { opacity: 0.5; cursor: not-allowed; }
.grade-btn.section-grade { display: block; margin: 0.5rem 0 0.5rem auto; }
.grade-btn.page-grade { display: block; margin: 2rem auto 1rem; padding: 0.5rem 2rem; font-size: 0.95rem; }

.grade-result {
  margin-top: 0.6rem;
  padding: 0.6rem 0.9rem;
  background: var(--blank-bg);
  border-left: 3px solid var(--accent);
  border-radius: 0 6px 6px 0;
  font-size: 0.88rem;
  white-space: pre-wrap;
  line-height: 1.6;
}
.grade-result.error { border-left-color: var(--red); color: var(--red); }

.grade-result.correct { border-left-color: var(--green); }
.grade-result.wrong { border-left-color: var(--red); }

.edited-mark {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--yellow);
  margin-top: 0.4rem;
}

/* print */
@media print {
  body { background: white; color: black; padding: 1rem; }
  .answer, .answer-btn { display: none !important; }
  .write-area { border: 1px solid #ccc; background: white; color: transparent; }
  input.blank { background: white; border-bottom: 1.5px solid black; color: black; }
  .nav-back { display: none; }
  h1, h2, h3 { color: black; }
  .question { border: 1px solid #ccc; background: white; }
  .q-type { border: 1px solid #999; }
}