/* ---------- base ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 500;
  line-height: 1.25;
  color: var(--text);
  margin: 0 0 0.5em;
}
a { color: var(--data); text-decoration: none; }
a:hover { text-decoration: underline; }
code, .mono { font-family: var(--font-mono); font-size: 0.86em; }
code {
  background: var(--bg-elevated);
  border: 1px solid var(--border-soft);
  border-radius: 5px;
  padding: 0.1em 0.4em;
}
button { font-family: var(--font-body); cursor: pointer; }
::selection { background: var(--accent-soft); }

/* ---------- app frame ---------- */
.app { display: flex; min-height: 100vh; }

.sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  width: var(--sidebar-w);
  background: var(--bg-raised);
  border-right: 1px solid var(--border-soft);
  display: flex;
  flex-direction: column;
  z-index: 30;
}
.view {
  flex: 1;
  margin-left: var(--sidebar-w);
  padding: 56px 48px 96px;
  min-width: 0;
  outline: none;
}

/* ---------- brand ---------- */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 22px 20px 18px;
  border-bottom: 1px solid var(--border-soft);
  color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 38px; height: 38px;
  display: grid; place-items: center;
  background: linear-gradient(135deg, var(--accent) 0%, #c77f1f 100%);
  color: #14110a;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 20px;
  border-radius: 9px;
  flex: none;
}
.brand-title { display: block; font-family: var(--font-display); font-size: 15.5px; font-weight: 500; }
.brand-sub { display: block; font-size: 11.5px; color: var(--text-faint); letter-spacing: 0.03em; }

/* ---------- nav ---------- */
.nav { flex: 1; overflow-y: auto; padding: 14px 10px; }
.nav-label {
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-faint);
  padding: 14px 10px 6px;
}
.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 10px;
  border-radius: 7px;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.35;
}
.nav-item:hover { background: var(--bg-hover); color: var(--text); text-decoration: none; }
.nav-item.active { background: var(--accent-soft); color: var(--accent-text); }
.nav-num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-faint);
  width: 18px;
  flex: none;
  text-align: right;
}
.nav-item.active .nav-num { color: var(--accent-text); }
.nav-done {
  margin-left: auto;
  color: var(--good);
  font-size: 12px;
  flex: none;
}

.sidebar-foot { padding: 14px; border-top: 1px solid var(--border-soft); }
.chat-open-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 11px;
  background: var(--bg-elevated);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 14.5px;
  font-weight: 600;
  transition: border-color 0.15s, background 0.15s;
}
.chat-open-btn:hover { border-color: var(--accent); background: var(--bg-hover); }
.chat-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent);
}

.sidebar-toggle { display: none; }

/* ---------- home ---------- */
.hero { max-width: 880px; margin-bottom: 44px; }
.hero h1 { font-size: 42px; letter-spacing: -0.01em; }
.hero .lede { font-size: 19px; color: var(--text-dim); max-width: var(--measure); }
.hero-meta { display: flex; gap: 22px; margin-top: 18px; font-size: 13.5px; color: var(--text-faint); }
.hero-meta strong { color: var(--accent-text); font-weight: 600; }

.section-label {
  font-size: 11.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin: 40px 0 14px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.section-label::after { content: ""; flex: 1; height: 1px; background: var(--border-soft); }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 14px;
  max-width: 1100px;
}
.mod-card {
  display: block;
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 20px 20px 18px;
  color: var(--text);
  transition: border-color 0.15s, transform 0.15s, background 0.15s;
}
.mod-card:hover {
  text-decoration: none;
  border-color: var(--border);
  background: var(--bg-elevated);
  transform: translateY(-2px);
}
.mod-card-top { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 10px; }
.mod-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-text);
  background: var(--accent-soft);
  border-radius: 6px;
  padding: 3px 8px;
}
.mod-card h3 { font-size: 19px; margin-bottom: 4px; }
.mod-card p { margin: 0; font-size: 14px; color: var(--text-dim); line-height: 1.55; }
.mod-card-foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 14px;
  font-size: 12.5px;
  color: var(--text-faint);
}
.mod-score { color: var(--good); font-weight: 600; }

.tool-card { border-left: 3px solid var(--data); }
.tool-card .mod-num { color: var(--data); background: var(--data-soft); }

/* progress ring */
.ring { width: 26px; height: 26px; transform: rotate(-90deg); }
.ring circle { fill: none; stroke-width: 3; }
.ring .ring-bg { stroke: var(--border); }
.ring .ring-fg { stroke: var(--good); stroke-linecap: round; }

/* ---------- module page ---------- */
.module-page { max-width: 860px; }
.mod-header { margin-bottom: 38px; padding-bottom: 26px; border-bottom: 1px solid var(--border-soft); }
.mod-kicker {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--accent-text);
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}
.mod-header h1 { font-size: 36px; letter-spacing: -0.01em; }
.mod-header .subtitle { font-size: 18px; color: var(--text-dim); margin: 6px 0 0; max-width: var(--measure); }

.module-page h2 {
  font-size: 26px;
  margin: 48px 0 14px;
  padding-top: 8px;
}
.module-page h3 { font-size: 20px; margin: 30px 0 10px; }
.module-page p, .module-page li { max-width: var(--measure); color: var(--text); }
.module-page p { margin: 0 0 1.1em; }
.module-page ul, .module-page ol { padding-left: 1.3em; margin: 0 0 1.2em; }
.module-page li { margin-bottom: 0.45em; }
.module-page strong { color: var(--text); font-weight: 700; }
.module-page em { color: var(--text-dim); }

.module-page table {
  border-collapse: collapse;
  margin: 8px 0 24px;
  font-size: 15px;
  width: 100%;
  max-width: 760px;
}
.module-page th {
  text-align: left;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-faint);
  border-bottom: 1px solid var(--border);
  padding: 8px 14px 8px 0;
}
.module-page td {
  border-bottom: 1px solid var(--border-soft);
  padding: 9px 14px 9px 0;
  vertical-align: top;
  color: var(--text-dim);
}
.module-page td:first-child { color: var(--text); }

/* diagram block */
.diagram-block {
  margin: 30px 0 36px;
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 26px 22px 14px;
}
.diagram-block svg { width: 100%; height: auto; display: block; }
.diagram-caption {
  font-size: 13px;
  color: var(--text-faint);
  text-align: center;
  margin-top: 12px;
  font-style: italic;
}

/* worked example */
.example-block {
  margin: 30px 0 36px;
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 22px 26px 14px;
}
.example-block .example-tag {
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-text);
  font-weight: 700;
  margin-bottom: 10px;
}
.example-block h3 { margin-top: 0; }

/* callouts */
.callout {
  margin: 26px 0;
  border-radius: var(--radius);
  padding: 16px 20px;
  font-size: 15.5px;
  max-width: 760px;
  border: 1px solid;
}
.callout p:last-child { margin-bottom: 0; }
.callout-tip { background: var(--good-soft); border-color: rgba(93, 187, 122, 0.3); }
.callout-warning { background: var(--warn-soft); border-color: rgba(224, 177, 62, 0.3); }
.callout-danger { background: var(--bad-soft); border-color: rgba(224, 108, 92, 0.3); }
.callout-note { background: var(--data-soft); border-color: rgba(92, 200, 222, 0.3); }
.callout .callout-tag {
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-weight: 700;
  display: block;
  margin-bottom: 6px;
}
.callout-tip .callout-tag { color: var(--good); }
.callout-warning .callout-tag { color: var(--warn); }
.callout-danger .callout-tag { color: var(--bad); }
.callout-note .callout-tag { color: var(--data); }

/* obsolete-practice strike block */
.obsolete {
  margin: 26px 0;
  padding: 16px 20px;
  border: 1px dashed var(--bad);
  border-radius: var(--radius);
  background: var(--bad-soft);
  max-width: 760px;
}
.obsolete .callout-tag { color: var(--bad); font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase; font-weight: 700; display: block; margin-bottom: 6px; }

/* footer nav between modules */
.mod-footer {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-top: 64px;
  padding-top: 26px;
  border-top: 1px solid var(--border-soft);
}
.mod-nav-link {
  flex: 1;
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 14px 18px;
  color: var(--text);
  transition: border-color 0.15s;
}
.mod-nav-link:hover { border-color: var(--accent); text-decoration: none; }
.mod-nav-link.next { text-align: right; }
.mod-nav-link .dir { font-size: 11.5px; color: var(--text-faint); text-transform: uppercase; letter-spacing: 0.1em; display: block; }
.mod-nav-link .t { font-family: var(--font-display); font-size: 16px; }

/* ---------- quiz ---------- */
.quiz {
  margin-top: 56px;
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 28px 30px;
}
.quiz-head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 18px; }
.quiz-head h2 { margin: 0; font-size: 23px; }
.quiz-best { font-size: 13px; color: var(--text-faint); }
.quiz-q { margin-bottom: 24px; }
.quiz-q-text { font-weight: 600; margin-bottom: 10px; max-width: var(--measure); }
.quiz-q-num { color: var(--accent-text); font-family: var(--font-mono); font-size: 13px; margin-right: 8px; }
.quiz-opt {
  display: block;
  width: 100%;
  text-align: left;
  background: var(--bg-elevated);
  border: 1px solid var(--border-soft);
  color: var(--text);
  border-radius: 8px;
  padding: 10px 14px;
  margin-bottom: 7px;
  font-size: 15px;
  line-height: 1.5;
  transition: border-color 0.12s, background 0.12s;
}
.quiz-opt:hover:not(:disabled) { border-color: var(--accent); }
.quiz-opt.selected { border-color: var(--accent); background: var(--accent-soft); }
.quiz-opt.correct { border-color: var(--good); background: var(--good-soft); }
.quiz-opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.quiz-opt:disabled { cursor: default; opacity: 0.85; }
.quiz-expl {
  font-size: 14.5px;
  color: var(--text-dim);
  background: var(--bg);
  border-radius: 8px;
  padding: 12px 16px;
  margin-top: 8px;
  border-left: 2px solid var(--data);
}
.quiz-actions { display: flex; align-items: center; gap: 16px; margin-top: 8px; }
.btn {
  background: var(--accent);
  color: #14110a;
  border: none;
  border-radius: 8px;
  padding: 11px 22px;
  font-size: 15px;
  font-weight: 700;
  transition: filter 0.12s;
}
.btn:hover { filter: brightness(1.08); }
.btn:disabled { opacity: 0.45; cursor: default; filter: none; }
.btn-ghost {
  background: transparent;
  color: var(--text-dim);
  border: 1px solid var(--border);
}
.btn-ghost:hover { color: var(--text); border-color: var(--text-faint); }
.quiz-result { font-size: 17px; font-weight: 700; }
.quiz-result.pass { color: var(--good); }
.quiz-result.fail { color: var(--warn); }

/* ---------- calculators ---------- */
.calc-page { max-width: 980px; }
.calc {
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 26px 28px;
  margin-bottom: 26px;
}
.calc h2 { margin: 0 0 6px; font-size: 23px; }
.calc .calc-desc { color: var(--text-dim); font-size: 15px; margin-bottom: 20px; max-width: var(--measure); }
.calc-body { display: grid; grid-template-columns: minmax(260px, 340px) 1fr; gap: 30px; }
.calc-inputs label { display: block; margin-bottom: 14px; font-size: 13.5px; color: var(--text-dim); }
.calc-inputs .lbl { display: block; margin-bottom: 5px; font-weight: 600; color: var(--text); }
.calc-inputs input, .calc-inputs select {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 9px 12px;
  font-size: 15.5px;
  font-family: var(--font-mono);
}
.calc-inputs input:focus { outline: none; border-color: var(--accent); }
.calc-out { display: flex; flex-direction: column; gap: 10px; }
.calc-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  background: var(--bg);
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  padding: 12px 16px;
}
.calc-row .k { font-size: 14px; color: var(--text-dim); }
.calc-row .v { font-family: var(--font-mono); font-size: 19px; color: var(--data); font-weight: 500; white-space: nowrap; }
.calc-row.highlight .v { color: var(--accent-text); }
.calc-row .note { display: block; font-size: 12px; color: var(--text-faint); }
.calc-verdict {
  margin-top: 4px;
  font-size: 14.5px;
  color: var(--text-dim);
  background: var(--bg);
  border-left: 2px solid var(--accent);
  border-radius: 8px;
  padding: 12px 16px;
}
.calc-verdict p { margin: 0 0 0.6em; }
.calc-verdict p:last-child { margin: 0; }
.band-good { color: var(--good); font-weight: 700; }
.band-ok { color: var(--warn); font-weight: 700; }
.band-bad { color: var(--bad); font-weight: 700; }

/* ---------- decision tree ---------- */
.tree {
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 28px 30px;
  max-width: 760px;
  margin: 26px 0;
}
.tree-crumbs { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 18px; min-height: 22px; }
.tree-crumb {
  font-size: 12px;
  color: var(--text-faint);
  background: var(--bg-elevated);
  border-radius: 5px;
  padding: 2px 9px;
}
.tree-crumb b { color: var(--text-dim); font-weight: 600; }
.tree-q { font-family: var(--font-display); font-size: 22px; margin-bottom: 6px; }
.tree-help { font-size: 14.5px; color: var(--text-dim); margin-bottom: 16px; }
.tree-answers { display: flex; flex-direction: column; gap: 8px; }
.tree-answer {
  text-align: left;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 12px 16px;
  font-size: 15.5px;
  transition: border-color 0.12s;
}
.tree-answer:hover { border-color: var(--accent); }
.tree-result { border-radius: var(--radius); padding: 18px 22px; border: 1px solid; }
.tree-result.severity-good { background: var(--good-soft); border-color: rgba(93,187,122,0.35); }
.tree-result.severity-warning { background: var(--warn-soft); border-color: rgba(224,177,62,0.35); }
.tree-result.severity-danger { background: var(--bad-soft); border-color: rgba(224,108,92,0.35); }
.tree-result h3 { margin: 0 0 8px; font-size: 20px; }
.tree-result .detail { font-size: 15px; color: var(--text); }
.tree-result .detail p { margin: 0 0 0.7em; }
.tree-links { margin-top: 12px; display: flex; gap: 10px; flex-wrap: wrap; }
.tree-links a {
  font-size: 13.5px;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 6px 12px;
  border-radius: 7px;
}
.tree-restart { margin-top: 18px; }

/* ---------- chat panel ---------- */
.chat-backdrop {
  position: fixed; inset: 0;
  background: rgba(8, 10, 14, 0.55);
  z-index: 40;
}
.chat-panel {
  position: fixed;
  top: 0; right: 0; bottom: 0;
  width: min(480px, 92vw);
  background: var(--bg-raised);
  border-left: 1px solid var(--border);
  box-shadow: var(--shadow);
  z-index: 50;
  display: flex;
  flex-direction: column;
  transform: translateX(102%);
  transition: transform 0.22s ease;
}
.chat-panel.open { transform: translateX(0); }
.chat-head {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  border-bottom: 1px solid var(--border-soft);
}
.chat-head h2 { margin: 0; font-size: 18px; flex: 1; }
.chat-model {
  background: var(--bg);
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 7px;
  font-size: 12.5px;
  padding: 5px 8px;
  font-family: var(--font-mono);
}
.chat-close { background: none; border: none; color: var(--text-faint); font-size: 20px; line-height: 1; padding: 4px 8px; }
.chat-close:hover { color: var(--text); }
.chat-disclaimer {
  font-size: 12px;
  color: var(--text-faint);
  padding: 8px 18px;
  border-bottom: 1px solid var(--border-soft);
  background: var(--bg);
}
.chat-log { flex: 1; overflow-y: auto; padding: 18px; display: flex; flex-direction: column; gap: 14px; }
.chat-msg { max-width: 92%; border-radius: 12px; padding: 11px 15px; font-size: 14.5px; line-height: 1.6; }
.chat-msg.user { align-self: flex-end; background: var(--accent-soft); border: 1px solid rgba(232,163,61,0.25); white-space: pre-wrap; }
.chat-msg.assistant { align-self: flex-start; background: var(--bg-elevated); border: 1px solid var(--border-soft); }
.chat-msg.assistant p { margin: 0 0 0.7em; }
.chat-msg.assistant p:last-child { margin: 0; }
.chat-msg.assistant ul, .chat-msg.assistant ol { margin: 0 0 0.7em; padding-left: 1.2em; }
.chat-msg.assistant h1, .chat-msg.assistant h2, .chat-msg.assistant h3 { font-size: 15.5px; font-family: var(--font-body); font-weight: 700; margin: 0.4em 0 0.3em; }
.chat-msg.error { align-self: stretch; background: var(--bad-soft); border: 1px solid rgba(224,108,92,0.35); color: var(--text); font-size: 13.5px; }
.chat-thinking { align-self: flex-start; color: var(--text-faint); font-size: 13px; padding: 4px 15px; }
.chat-thinking::after { content: "…"; animation: pulse 1.2s infinite; }
@keyframes pulse { 0%,100% { opacity: 0.3; } 50% { opacity: 1; } }
.chat-foot { padding: 12px 14px 14px; border-top: 1px solid var(--border-soft); }
.chat-templates { display: flex; gap: 8px; margin-bottom: 10px; flex-wrap: wrap; }
.chat-template-btn {
  font-size: 12px;
  background: var(--bg-elevated);
  color: var(--text-dim);
  border: 1px solid var(--border-soft);
  border-radius: 999px;
  padding: 4px 12px;
}
.chat-template-btn:hover { color: var(--text); border-color: var(--border); }
.chat-input-row { display: flex; gap: 8px; align-items: flex-end; }
.chat-input {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 10px;
  padding: 10px 13px;
  font-size: 14.5px;
  font-family: var(--font-body);
  resize: none;
  max-height: 160px;
  line-height: 1.5;
}
.chat-input:focus { outline: none; border-color: var(--accent); }
.chat-send {
  background: var(--accent);
  color: #14110a;
  border: none;
  border-radius: 10px;
  width: 42px; height: 42px;
  font-size: 17px;
  font-weight: 700;
  flex: none;
}
.chat-send:disabled { opacity: 0.4; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); transition: transform 0.2s ease; }
  .sidebar.open { transform: translateX(0); box-shadow: var(--shadow); }
  .view { margin-left: 0; padding: 72px 22px 80px; }
  .sidebar-toggle {
    display: grid;
    place-items: center;
    position: fixed;
    top: 14px; left: 14px;
    z-index: 35;
    width: 42px; height: 42px;
    background: var(--bg-elevated);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 17px;
  }
  .hero h1 { font-size: 30px; }
  .mod-header h1 { font-size: 27px; }
  .calc-body { grid-template-columns: 1fr; }
}