:root {
  --blush: #f7e7e9;
  --rose: #d98a96;
  --ink: #3a2e30;
  --ok: #2e7d52;
  --err: #b5485a;
}
* {
  box-sizing: border-box;
}
body {
  font-family: "Apple SD Gothic Neo", "Pretendard", sans-serif;
  max-width: 720px;
  margin: 0 auto;
  padding: 1rem;
  color: var(--ink);
  background: #fffafa;
  line-height: 1.7;
}
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
h1 {
  color: var(--rose);
}
.teacher-toggle {
  font-size: 0.85rem;
  color: #999;
}
#loading {
  padding: 1rem;
  background: var(--blush);
  border-radius: 12px;
  text-align: center;
}
.lesson-text {
  margin: 1.2rem 0;
}
.lesson-text blockquote {
  border-left: 3px solid var(--rose);
  margin: 0.5rem 0;
  padding: 0.2rem 0.9rem;
  background: var(--blush);
  color: #7a5c60;
}
.code-cell {
  margin: 1rem 0;
  border: 1px solid var(--blush);
  border-radius: 12px;
  overflow: hidden;
}
.code-input {
  width: 100%;
  border: none;
  padding: 0.8rem;
  font-family: "SF Mono", Menlo, monospace;
  font-size: 0.95rem;
  background: #2b2b2b;
  color: #f5f5f5;
  resize: vertical;
}
.code-controls {
  display: flex;
  gap: 0.5rem;
  padding: 0.5rem;
  background: var(--blush);
}
.run-btn,
.reset-btn {
  border: none;
  border-radius: 8px;
  padding: 0.4rem 0.9rem;
  cursor: pointer;
}
.run-btn {
  background: var(--rose);
  color: white;
  font-weight: bold;
}
.reset-btn {
  background: white;
  color: #999;
}
.code-output {
  margin: 0;
  padding: 0.8rem;
  white-space: pre-wrap;
  min-height: 1rem;
  font-family: "SF Mono", Menlo, monospace;
}
.code-output.ok {
  background: #eef8f1;
  color: var(--ok);
}
.code-output.err {
  background: #fcecee;
  color: var(--err);
}
/* 선생 메모: 기본 숨김, 선생님 모드에서만 */
.teacher-note {
  display: none;
  margin: 1rem 0;
  border: 1px dashed var(--rose);
  border-radius: 10px;
  padding: 0.3rem 0.8rem;
}
body.show-teacher .teacher-note {
  display: block;
}
.teacher-note summary {
  cursor: pointer;
  color: var(--rose);
  font-weight: bold;
}
#layout {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}
#sidebar {
  flex: 0 0 200px;
  position: sticky;
  top: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
#lessons {
  flex: 1;
  min-width: 0;
}
.toc-phase {
  font-size: 0.8rem;
  font-weight: bold;
  margin-top: 0.6rem;
}
.toc-phase.site {
  color: var(--rose);
}
.toc-phase.later {
  color: #c4b5b8;
  font-weight: normal;
}
.week-link {
  text-align: left;
  border: 1px solid var(--blush);
  background: white;
  border-radius: 10px;
  padding: 0.5rem 0.7rem;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  font-family: inherit;
}
.week-link b {
  color: var(--ink);
  font-size: 0.9rem;
}
.week-link span {
  color: #a98;
  font-size: 0.75rem;
}
.week-link:hover {
  background: var(--blush);
}
.week-link.active {
  background: var(--rose);
}
.week-link.active b,
.week-link.active span {
  color: white;
}
.placeholder {
  color: #999;
}
@media (max-width: 640px) {
  #layout {
    flex-direction: column;
  }
  #sidebar {
    flex: none;
    width: 100%;
    position: static;
    flex-direction: row;
    flex-wrap: wrap;
  }
  #sidebar .toc-phase {
    width: 100%;
  }
}
.pw-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}
.pw-box {
  background: white;
  padding: 1.5rem;
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  min-width: 240px;
}
.pw-box p {
  margin: 0;
  font-weight: bold;
  color: var(--rose);
}
.pw-input {
  padding: 0.5rem;
  border: 1px solid var(--blush);
  border-radius: 8px;
  font-size: 1rem;
}
.pw-btns {
  display: flex;
  gap: 0.5rem;
  justify-content: flex-end;
}
.pw-btns button {
  border: none;
  border-radius: 8px;
  padding: 0.4rem 0.9rem;
  cursor: pointer;
}
.pw-ok {
  background: var(--rose);
  color: white;
  font-weight: bold;
}
.pw-cancel {
  background: #eee;
  color: #666;
}