:root {
  --bg: #faf9f6;
  --surface: #ffffff;
  --border: #e6e3da;
  --text: #1c1c1a;
  --text-muted: #6f6d64;
  --accent: #7a9b3f;
  --accent-strong: #5c7a2b;
  --accent-soft: #eaf1dc;
  --radius: 14px;
  --font-body: 'Manrope', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.topbar {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  font-weight: 800;
  text-decoration: none;
  letter-spacing: 0.01em;
  font-size: 18px;
}

.topbar__logout {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
}
.topbar__email {
  font-size: 13px;
  color: var(--text-muted);
}
.topbar__logout-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 14px;
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
}
.topbar__logout-btn:hover { border-color: var(--accent); }

/* ---- auth pages ---- */
.auth-wrap {
  max-width: 380px;
  margin: 40px auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.auth-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 26px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.auth-card--nested {
  margin-top: 10px;
  padding: 20px;
}

.auth-card h1 {
  font-size: 22px;
  margin: 0 0 4px;
}

.auth-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  color: var(--text-muted);
}
.auth-field input {
  font-family: var(--font-body);
  font-size: 15px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  background: var(--bg);
}
.auth-field input:focus {
  outline: none;
  border-color: var(--accent);
}

.auth-submit { width: 100%; justify-content: center; }

.auth-note {
  font-size: 13px;
  color: var(--text-muted);
  margin: 0;
}
.auth-note--error { color: #b3413a; }
.auth-note--warn { color: #a6740f; }

.auth-recover summary {
  cursor: pointer;
  font-size: 14px;
  color: var(--accent-strong);
  font-weight: 600;
  text-align: center;
}

.page {
  max-width: 1100px;
  margin: 0 auto;
  padding: 28px 20px 64px;
}

/* ---- progress bar ---- */
.progress {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 10px;
}
.progress__track {
  flex: 1;
  height: 8px;
  background: var(--border);
  border-radius: 999px;
  overflow: hidden;
  max-width: 260px;
}
.progress__fill {
  height: 100%;
  background: var(--accent);
  border-radius: 999px;
  transition: width .3s ease;
}
.progress__label {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  white-space: nowrap;
}

/* ---- home ---- */
.home-head h1 {
  font-size: clamp(26px, 4vw, 34px);
  margin: 0 0 4px;
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 18px;
  margin-top: 26px;
}

.module-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px 12px;
}

.module-card__head h2 {
  font-size: 19px;
  margin: 0;
}

.lesson-list {
  list-style: none;
  margin: 14px 0 4px;
  padding: 0;
}

.lesson-row a {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  padding: 9px 4px;
  border-radius: 8px;
  color: var(--text);
}
.lesson-row a:hover { background: var(--accent-soft); }
.lesson-row--empty { color: var(--text-muted); padding: 9px 4px; font-size: 14px; }

.lesson-row__check {
  width: 20px;
  height: 20px;
  flex: none;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  color: var(--accent-strong);
}
.lesson-row.is-done .lesson-row__check {
  background: var(--accent-soft);
  border-color: var(--accent);
}
.lesson-row.is-done .lesson-row__title { color: var(--text-muted); }

.empty-state { color: var(--text-muted); }

/* ---- lesson page ---- */
.lesson-layout {
  display: flex;
  gap: 32px;
  align-items: flex-start;
}

.toc-toggle {
  display: none;
}

.toc-wrap {
  flex: none;
  width: 260px;
  position: sticky;
  top: 20px;
}

.toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  max-height: calc(100vh - 40px);
  overflow-y: auto;
}

.side-module { margin-bottom: 14px; }
.side-module:last-child { margin-bottom: 0; }
.side-module__title {
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  padding: 4px 8px;
}
.side-module ul { list-style: none; margin: 0; padding: 0; }

.side-lesson {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text);
  font-size: 14px;
  padding: 7px 8px;
  border-radius: 8px;
}
.side-lesson:hover { background: var(--accent-soft); }
.side-lesson.is-current {
  background: var(--accent-soft);
  font-weight: 700;
}
.side-lesson.is-done { color: var(--text-muted); }
.side-lesson__check {
  width: 15px;
  flex: none;
  font-size: 12px;
  color: var(--accent-strong);
}

.lesson {
  flex: 1;
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px clamp(18px, 4vw, 48px) 40px;
}

.lesson__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-strong);
  margin-bottom: 10px;
}

.lesson__content {
  font-size: 17px;
  max-width: 68ch;
}
.lesson__content h1 { font-size: clamp(24px, 3.4vw, 32px); line-height: 1.2; margin: 0 0 20px; }
.lesson__content h2 { font-size: 22px; margin: 32px 0 12px; }
.lesson__content h3 { font-size: 18px; margin: 26px 0 10px; }
.lesson__content p { margin: 0 0 16px; }
.lesson__content ul, .lesson__content ol { margin: 0 0 16px; padding-left: 1.3em; }
.lesson__content li { margin-bottom: 6px; }
.lesson__content img { max-width: 100%; border-radius: 10px; }
.lesson__content blockquote {
  margin: 0 0 16px;
  padding: 4px 16px;
  border-left: 3px solid var(--accent);
  color: var(--text-muted);
}
.lesson__content code {
  font-family: var(--font-mono);
  background: var(--accent-soft);
  padding: 2px 6px;
  border-radius: 5px;
  font-size: 0.9em;
}
.lesson__content pre {
  background: #1c1c1a;
  color: #f4f2ea;
  padding: 16px;
  border-radius: 10px;
  overflow-x: auto;
}
.lesson__content pre code { background: none; padding: 0; color: inherit; }
.lesson__content a { color: var(--accent-strong); }
.lesson__content hr { border: none; border-top: 1px solid var(--border); margin: 28px 0; }

.lesson__actions {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.lesson__nav {
  display: flex;
  gap: 10px;
  margin-left: auto;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: none;
  border-radius: 999px;
  padding: 11px 20px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 14px;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
}
.btn--primary { background: var(--accent); color: #fff; }
.btn--primary:hover { background: var(--accent-strong); }
.btn--done { background: var(--accent-soft); color: var(--accent-strong); }
.btn--ghost {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
}
.btn--ghost:hover { border-color: var(--accent); }

/* ---- mobile ---- */
@media (max-width: 860px) {
  .lesson-layout { flex-direction: column; }

  .toc-toggle {
    display: block;
    width: 100%;
    text-align: left;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px 14px;
    font-family: var(--font-body);
    font-weight: 700;
    font-size: 14px;
    color: var(--text);
  }

  .toc-wrap {
    width: 100%;
    position: static;
    display: none;
  }
  .toc-wrap.is-open { display: block; margin-top: 10px; }

  .toc { max-height: 50vh; }

  .lesson { padding: 24px 18px 32px; }

  .lesson__actions { flex-direction: column; align-items: stretch; }
  .lesson__nav { margin-left: 0; justify-content: space-between; }
  .btn { justify-content: center; flex: 1; }
}