:root {
  --bg: #f4f5f7;
  --panel: #ffffff;
  --border: #dde1e6;
  --text: #1c2128;
  --muted: #5c636e;
  --accent: #1a5fb4;
  --accent-text: #ffffff;
  --result-bg: #eef5ff;
  --result-border: #b8d4f5;
  --warn-bg: #fff6e5;
  --warn-border: #f0d38a;
  --nav-bg: #ffffff;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16181d;
    --panel: #1e2128;
    --border: #33383f;
    --text: #e8eaed;
    --muted: #9aa1ab;
    --accent: #4d94ff;
    --accent-text: #0b1220;
    --result-bg: #10233f;
    --result-border: #2c5a94;
    --warn-bg: #332a10;
    --warn-border: #7a5c1e;
    --nav-bg: #1e2128;
  }
}
* { box-sizing: border-box; }
html, body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
body {
  display: flex;
  justify-content: center;
  padding-bottom: calc(64px + env(safe-area-inset-bottom));
}
.app {
  width: 100%;
  max-width: 560px;
  padding: 1rem 1rem 0.5rem;
}
h1 {
  font-size: 1.4rem;
  margin: 0.2rem 0 0.1rem;
}
h2 {
  font-size: 1.1rem;
  margin: 0 0 0.6rem;
}
h3 {
  font-size: 0.95rem;
  margin: 0 0 0.3rem;
}
.subtitle {
  color: var(--muted);
  font-size: 0.85rem;
  margin-bottom: 1.2rem;
}
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.1rem;
  margin-bottom: 1rem;
}
.row {
  display: flex;
  gap: 0.6rem;
  margin-bottom: 0.85rem;
}
.row > div { flex: 1; }
label {
  display: block;
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 0.3rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}
select, input[type=number], input[type=search], input[type=text], input[type=date], textarea {
  width: 100%;
  padding: 0.55rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
}
textarea { resize: vertical; }
.unit-toggle {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}
.unit-toggle button {
  flex: 1;
  padding: 0.5rem;
  border: none;
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
  font-size: 0.9rem;
}
.unit-toggle button.active {
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 600;
}
.hint {
  font-size: 0.72rem;
  color: var(--muted);
  margin-top: 0.25rem;
}
.results {
  background: var(--result-bg);
  border: 1px solid var(--result-border);
  border-radius: 10px;
  padding: 1rem 1.1rem;
}
.result-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.4rem 0;
}
.result-row + .result-row {
  border-top: 1px dashed var(--result-border);
}
.result-label {
  color: var(--muted);
  font-size: 0.85rem;
}
.result-value {
  font-size: 1.3rem;
  font-weight: 700;
}
.result-value .unit {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--muted);
  margin-left: 0.2rem;
}
.note {
  background: var(--warn-bg);
  border: 1px solid var(--warn-border);
  border-radius: 8px;
  padding: 0.7rem 0.9rem;
  font-size: 0.8rem;
  color: var(--text);
  margin-top: 1rem;
  line-height: 1.4;
}
.field-group {
  display: none;
}
.field-group.active {
  display: block;
}

/* Tab panels */
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* Bottom nav */
.tabbar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  background: var(--nav-bg);
  border-top: 1px solid var(--border);
  padding-bottom: env(safe-area-inset-bottom);
  z-index: 10;
}
.tabbar button {
  flex: 1;
  background: none;
  border: none;
  color: var(--muted);
  padding: 0.5rem 0.2rem 0.45rem;
  font-size: 0.68rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  cursor: pointer;
}
.tabbar button .icon { font-size: 1.25rem; }
.tabbar button.active { color: var(--accent); font-weight: 700; }

/* G-code reference */
.gcode-list { display: flex; flex-direction: column; gap: 0.5rem; }
.gcode-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.55rem 0.8rem;
  display: flex;
  gap: 0.8rem;
  align-items: baseline;
}
.gcode-code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-weight: 700;
  color: var(--accent);
  min-width: 3.2rem;
}
.gcode-desc { flex: 1; font-size: 0.9rem; }
.gcode-cat {
  font-size: 0.68rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.02em;
}
.section-heading {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--muted);
  margin: 1rem 0 0.4rem;
  font-weight: 700;
}
.section-heading:first-child { margin-top: 0; }

/* Curriculum accordion */
details.subject {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.9rem;
  margin-bottom: 0.5rem;
}
details.subject summary {
  cursor: pointer;
  font-weight: 700;
  font-size: 0.92rem;
}
details.subject .module {
  margin-top: 0.6rem;
  padding-top: 0.5rem;
  border-top: 1px dashed var(--border);
}
details.subject .module:first-of-type { border-top: none; margin-top: 0.5rem; }
details.subject .module-title {
  font-weight: 600;
  font-size: 0.85rem;
  margin-bottom: 0.15rem;
}
ul.module-topics {
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.5;
  margin: 0;
  padding-left: 1.1rem;
}
ul.module-topics li { margin-bottom: 0.15rem; }

/* Journal */
.subtab-bar {
  display: flex;
  gap: 0.4rem;
  margin-bottom: 1rem;
}
.subtab-bar .subtab {
  flex: 1;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--muted);
  border-radius: 999px;
  padding: 0.45rem 0.4rem;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
}
.subtab-bar .subtab.active {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}
.subtab-panel { display: none; }
.subtab-panel.active { display: block; }

#journal form.panel label { margin-top: 0.7rem; }
#journal form.panel label:first-of-type { margin-top: 0; }
#journal form.panel .row { margin-bottom: 0; }
#journal textarea { margin-top: 0.3rem; }

.add-btn {
  display: block;
  width: 100%;
  margin-top: 0.9rem;
  padding: 0.6rem;
  border: none;
  border-radius: 6px;
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 700;
  font-size: 0.92rem;
  cursor: pointer;
}
.add-btn.secondary {
  background: var(--panel);
  color: var(--accent);
  border: 1px solid var(--border);
  margin-top: 0;
}

.journal-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.8rem;
  margin-bottom: 0.5rem;
}
.journal-item.past { opacity: 0.55; }
.journal-item-head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.journal-date {
  font-size: 0.78rem;
  color: var(--muted);
  font-weight: 600;
}
.journal-subject {
  font-size: 0.85rem;
  font-weight: 700;
  flex: 1;
}
.journal-badge {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  white-space: nowrap;
}
.badge-normal { background: var(--result-bg); color: var(--accent); border: 1px solid var(--result-border); }
.badge-soon { background: var(--warn-bg); color: var(--text); border: 1px solid var(--warn-border); }
.badge-past { background: var(--bg); color: var(--muted); border: 1px solid var(--border); }
.journal-del, .journal-cal, .journal-check {
  border: none;
  background: none;
  color: var(--muted);
  font-size: 0.9rem;
  cursor: pointer;
  padding: 0.1rem 0.2rem;
}
.journal-check { font-size: 1.1rem; color: var(--accent); }
.journal-text {
  font-size: 0.85rem;
  margin-top: 0.35rem;
  line-height: 1.4;
}

/* Resources */
.resource-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.7rem 0.9rem;
  margin-bottom: 0.5rem;
}
.resource-item a {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
  font-size: 0.92rem;
}
.resource-item .desc {
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 0.2rem;
  line-height: 1.4;
}
.tip-list {
  padding-left: 1.1rem;
  font-size: 0.88rem;
  line-height: 1.6;
}
.tip-list li { margin-bottom: 0.4rem; }