:root {
  --bg: #f5f1e8;
  --paper: #fffdf8;
  --ink: #202124;
  --muted: #4d555c;
  --line: #ddd3c3;
  --red: #b83a2f;
  --blue: #1f5c99;
  --green: #2f7d64;
  --gold: #c78920;
  --soft-blue: #e9f2fb;
  --soft-green: #e8f4ed;
  --soft-red: #f8e9e7;
  --shadow: 0 14px 36px rgba(36, 30, 20, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Microsoft JhengHei", "Noto Sans TC", Arial, sans-serif;
}

button,
input,
textarea,
select {
  font: inherit;
}

.topbar {
  min-height: 104px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 22px 32px;
  background: #fffaf0;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--red);
  font-weight: 700;
  font-size: 0.82rem;
  letter-spacing: 0;
}

h1,
h2,
h3 {
  margin: 0;
  letter-spacing: 0;
}

h1 {
  font-size: clamp(1.6rem, 3vw, 2.3rem);
}

h2 {
  font-size: clamp(1.45rem, 2.6vw, 2.15rem);
}

h3 {
  font-size: 1.22rem;
}

.status-pill {
  padding: 10px 14px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--muted);
  border-radius: 8px;
  white-space: nowrap;
}

.layout {
  display: grid;
  grid-template-columns: minmax(270px, 320px) 1fr;
  gap: 24px;
  padding: 24px;
  max-width: 1440px;
  margin: 0 auto;
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.panel,
.card,
.activity-card,
.upload-card,
.submit-card,
.visual-card,
.study-card,
.source-card,
.hero {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.panel {
  padding: 18px;
}

.panel.compact {
  box-shadow: none;
}

.student-form,
.activity-form {
  display: grid;
  gap: 12px;
}

label {
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 700;
}

input,
textarea,
select {
  width: 100%;
  border: 1px solid #cfc5b7;
  background: #fff;
  color: var(--ink);
  border-radius: 6px;
  padding: 10px 11px;
  outline: none;
}

textarea {
  resize: vertical;
}

input:focus,
textarea:focus,
select:focus {
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(31, 92, 153, 0.12);
}

button {
  border: 1px solid #c9bba8;
  background: #fff;
  color: var(--ink);
  border-radius: 6px;
  padding: 10px 12px;
  cursor: pointer;
  font-weight: 700;
}

button:hover {
  background: #f8f3ea;
}

button.primary {
  background: var(--red);
  border-color: var(--red);
  color: #fff;
}

button.primary:hover {
  background: #a63128;
}

button.large {
  min-height: 52px;
  font-size: 1.05rem;
}

button.danger {
  color: #8b231d;
}

.button-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.button-row.end {
  justify-content: flex-end;
}

.unit-nav {
  display: grid;
  gap: 10px;
}

.unit-tab {
  width: 100%;
  text-align: left;
  background: #fff;
}

.unit-tab.active {
  border-color: var(--red);
  background: var(--soft-red);
}

.unit-tab span {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
  margin-top: 2px;
}

.content {
  display: grid;
  gap: 18px;
  min-width: 0;
}

.hero {
  min-height: 230px;
  padding: 32px;
  display: flex;
  align-items: flex-end;
  background:
    linear-gradient(90deg, rgba(255, 253, 248, 0.96), rgba(255, 253, 248, 0.68)),
    var(--hero-image, none) center / cover no-repeat,
    var(--paper);
}

.hero p:not(.eyebrow) {
  max-width: 760px;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.7;
}

.learning-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.card {
  padding: 22px;
}

.study-card,
.source-card {
  padding: 22px;
}

.study-sections {
  display: grid;
  gap: 14px;
}

.study-block {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.study-block:first-child {
  border-top: 0;
  padding-top: 0;
}

.study-block h4 {
  margin: 0 0 8px;
  color: var(--blue);
  font-size: 1.05rem;
}

.study-block p {
  margin: 0;
  color: var(--muted);
  line-height: 1.8;
}

.concept-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 14px;
}

.concept-chip {
  padding: 12px;
  border-radius: 8px;
  border: 1px solid #bed5ec;
  background: var(--soft-blue);
  line-height: 1.5;
}

.concept-chip strong {
  display: block;
  margin-bottom: 4px;
  color: var(--blue);
}

.source-card a {
  color: var(--blue);
  font-weight: 700;
}

ul {
  margin: 14px 0 0;
  padding-left: 1.25rem;
  line-height: 1.75;
}

.visual-card {
  display: grid;
  grid-template-columns: minmax(220px, 0.85fr) minmax(320px, 1.3fr);
  gap: 20px;
  padding: 22px;
  align-items: center;
}

.visual-card p {
  line-height: 1.75;
  color: var(--muted);
}

.visual-card img {
  width: 100%;
  max-height: 420px;
  object-fit: contain;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.annotated-figure {
  display: grid;
  gap: 12px;
}

.image-stage {
  position: relative;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.image-stage img {
  display: block;
  border: 0;
  border-radius: 0;
}

.marker-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.part-marker {
  position: absolute;
  width: 30px;
  height: 30px;
  transform: translate(-50%, -50%);
  border: 2px solid #fff;
  border-radius: 50%;
  background: var(--red);
  color: #fff;
  display: grid;
  place-items: center;
  font-weight: 900;
  box-shadow: 0 4px 14px rgba(32, 33, 36, 0.28);
  color: #fff !important;
}

.part-marker.blue {
  background: var(--blue);
}

.part-marker.green {
  background: var(--green);
}

.part-marker.gold {
  background: var(--gold);
}

.part-legend {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.legend-item {
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 8px;
  align-items: start;
  padding: 10px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.legend-code {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--red);
  color: #fff !important;
  display: grid;
  place-items: center;
  font-weight: 900;
}

.legend-item strong {
  display: block;
  margin-bottom: 3px;
}

.legend-item span {
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.image-question-layout {
  display: grid;
  grid-template-columns: minmax(280px, 1fr) minmax(240px, 0.9fr);
  gap: 14px;
  align-items: start;
}

.mini-figure {
  position: relative;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.mini-figure img {
  display: block;
  width: 100%;
}

.image-answer-grid {
  display: grid;
  gap: 10px;
}

.image-answer-row {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 8px;
  align-items: center;
}

.image-answer-row strong {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--blue);
  color: #fff;
  display: grid;
  place-items: center;
}

.activity-card,
.upload-card,
.submit-card {
  padding: 22px;
}

.section-heading {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
  margin-bottom: 18px;
}

.question {
  border-top: 1px solid var(--line);
  padding: 18px 0;
  display: grid;
  gap: 12px;
}

.question:first-child {
  border-top: 0;
  padding-top: 0;
}

.question-title {
  color: var(--ink);
  font-weight: 800;
  line-height: 1.6;
}

.options {
  display: grid;
  gap: 8px;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px;
  border: 1px solid #ded5c9;
  border-radius: 6px;
  background: #fff;
  color: var(--ink);
  font-weight: 500;
}

.option input {
  width: auto;
  margin-top: 4px;
}

.match-grid {
  display: grid;
  grid-template-columns: minmax(120px, 220px) 1fr;
  gap: 10px;
  align-items: center;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(110px, 1fr));
  gap: 12px;
}

.calc-result {
  padding: 14px;
  background: var(--soft-blue);
  border: 1px solid #bed5ec;
  border-radius: 6px;
  line-height: 1.7;
}

.hint {
  color: var(--muted);
  line-height: 1.65;
  font-size: 0.95rem;
}

.photo-preview {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.photo-item {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
}

.photo-item img {
  width: 100%;
  height: 130px;
  object-fit: cover;
  display: block;
}

.photo-item p {
  margin: 0;
  padding: 8px 10px;
  color: var(--muted);
  font-size: 0.85rem;
  line-height: 1.4;
}

dialog {
  width: min(860px, calc(100% - 32px));
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 20px;
}

dialog textarea {
  font-family: Consolas, monospace;
  font-size: 0.86rem;
}

@media (max-width: 960px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    order: 2;
  }

  .visual-card,
  .learning-grid,
  .image-question-layout {
    grid-template-columns: 1fr;
  }

  .concept-strip {
    grid-template-columns: 1fr;
  }

  .part-legend {
    grid-template-columns: 1fr;
  }

  .calc-grid {
    grid-template-columns: repeat(2, minmax(120px, 1fr));
  }
}

@media (max-width: 560px) {
  .topbar,
  .layout {
    padding: 16px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero,
  .card,
  .activity-card,
  .upload-card,
  .submit-card,
  .visual-card,
  .study-card,
  .source-card,
  .panel {
    padding: 16px;
  }

  .calc-grid {
    grid-template-columns: 1fr;
  }
}