/* BambuHelper Web Flasher
   Direction: dev-docs layout. Sticky left rail (brand + TOC + links),
   main content column to the right. Zinc neutrals + one cyan accent
   (CLR_CYAN from the device's own AP screen).
   Geist Sans for UI, Geist Mono for technical content. */

:root {
  --bg:         #09090b;
  --bg-elev-1:  #0e0e11;
  --bg-elev-2:  #131318;
  --bg-inset:   #0a0a0d;
  --border:     #1f1f25;
  --border-soft:#16161b;
  --border-strong:#2a2a32;

  --fg:         #e7e7ea;
  --fg-bright:  #fafafa;
  --fg-mute:    #a1a1aa;
  --fg-dim:     #71717a;
  --fg-faint:   #52525b;

  --accent:     #22d3ee;
  --accent-fg:  #0a0a0d;
  --accent-soft:rgba(34, 211, 238, 0.12);
  --accent-line:rgba(34, 211, 238, 0.32);

  --ok:    #4ade80;
  --warn:  #facc15;
  --err:   #f87171;

  --sans: "Geist", ui-sans-serif, system-ui, -apple-system, "Segoe UI",
          "Helvetica Neue", Arial, sans-serif;
  --mono: "Geist Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 14px;

  --rail-width: 224px;
  --rail-gap:   72px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  font-feature-settings: "ss01", "cv11";
}

body::before {
  content: "";
  position: fixed;
  inset: 0 0 auto 0;
  height: 540px;
  pointer-events: none;
  background:
    radial-gradient(900px 280px at 40% -40px,
      rgba(34, 211, 238, 0.06), transparent 70%);
  z-index: 0;
}

/* ────────── shell + layout ────────── */

.shell {
  position: relative;
  z-index: 1;
  max-width: 1280px;
  margin: 0 auto;
  padding: 36px 56px 72px;
}

.layout {
  display: grid;
  grid-template-columns: var(--rail-width) minmax(0, 1fr);
  gap: var(--rail-gap);
  align-items: start;
}

/* ────────── left rail ────────── */

.rail {
  position: sticky;
  top: 36px;
  align-self: start;
  max-height: calc(100vh - 72px);
  overflow-y: auto;
  padding-right: 8px;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}
.rail::-webkit-scrollbar { width: 6px; }
.rail::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 999px; }

.rail-inner {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}
.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: linear-gradient(135deg, #1a1a22 0%, #0e0e11 100%);
  border: 1px solid var(--border-strong);
  display: grid;
  place-items: center;
  flex: none;
}
.brand-mark::after {
  content: "";
  width: 11px;
  height: 11px;
  border-radius: 2px;
  background: var(--accent);
  box-shadow: 0 0 14px var(--accent-line);
}
.brand-text { min-width: 0; }
.brand-name {
  font-weight: 600;
  color: var(--fg-bright);
  letter-spacing: -0.01em;
  font-size: 15px;
  line-height: 1.15;
}
.brand-sub {
  color: var(--fg-dim);
  font-family: var(--mono);
  font-size: 11.5px;
  line-height: 1.4;
}

.rail-label {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-faint);
  margin-bottom: 10px;
}

.toc {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.toc-item {
  display: grid;
  grid-template-columns: 30px 1fr;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  margin-left: -10px;
  border-radius: 8px;
  font-size: 13.5px;
  color: var(--fg-mute);
  border: 0;
  text-decoration: none;
  transition: background 120ms ease, color 120ms ease;
  position: relative;
}
.toc-item .toc-num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-faint);
  letter-spacing: 0.04em;
}
.toc-item:hover {
  background: var(--bg-elev-1);
  color: var(--fg-bright);
}
.toc-item:hover .toc-num { color: var(--fg-mute); }
.toc-item.is-active {
  color: var(--fg-bright);
  background: var(--bg-elev-1);
}
.toc-item.is-active::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  border-radius: 2px;
  background: var(--accent);
}
.toc-item.is-active .toc-num { color: var(--accent); }

.rail-links {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.rail-links a {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--fg-mute);
  padding: 5px 0;
  border-bottom: 0;
  transition: color 120ms ease;
}
.rail-links a:hover { color: var(--fg-bright); }

.rail-foot {
  margin-top: auto;
  padding-top: 16px;
  border-top: 1px solid var(--border-soft);
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-faint);
}
.rail-foot .rail-version span { color: var(--fg-dim); }

/* ────────── main column ────────── */

.main { min-width: 0; }

/* ────────── hero ────────── */

.hero {
  margin-bottom: 36px;
  padding-top: 4px;
}
.hero h1 {
  margin: 0 0 14px;
  font-size: 48px;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--fg-bright);
  font-weight: 600;
  text-wrap: balance;
  max-width: 18ch;
}
.hero h1 .accent { color: var(--accent); }
.hero p {
  margin: 0;
  max-width: 64ch;
  color: var(--fg-mute);
  font-size: 16.5px;
  text-wrap: pretty;
}

/* ────────── browser support callout ────────── */

.browser-callout {
  display: none;
  margin: 0 0 32px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  background: var(--bg-elev-1);
  border-radius: var(--r-md);
  color: var(--fg-mute);
  font-size: 14px;
  gap: 12px;
  align-items: flex-start;
  max-width: 640px;
}
.browser-callout.show { display: flex; }
.browser-callout strong { color: var(--fg-bright); font-weight: 600; display: block; margin-bottom: 2px; }
.browser-callout .pulse {
  flex: none;
  width: 8px;
  height: 8px;
  margin-top: 7px;
  border-radius: 999px;
  background: var(--warn);
  box-shadow: 0 0 0 4px rgba(250, 204, 21, 0.12);
}

/* ────────── panels ────────── */

.panel {
  border-top: 1px solid var(--border-soft);
  padding: 36px 0;
}
.panel:last-of-type { padding-bottom: 12px; }

.panel-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 22px;
}
.panel-head .num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-dim);
  padding: 3px 8px;
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: 6px;
  letter-spacing: 0.04em;
}
.panel-head h2 {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.015em;
  color: var(--fg-bright);
  scroll-margin-top: 36px;
}

.lede {
  margin: 0 0 18px;
  max-width: 68ch;
  color: var(--fg-mute);
  font-size: 15px;
  text-wrap: pretty;
}

/* ────────── form: board select ────────── */

.field-label {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--fg-dim);
  margin: 0 0 8px;
}

.select-wrap {
  position: relative;
  max-width: 560px;
  margin-bottom: 22px;
}
.select-wrap::after {
  content: "";
  position: absolute;
  right: 14px;
  top: 50%;
  width: 8px;
  height: 8px;
  border-right: 1.5px solid var(--fg-mute);
  border-bottom: 1.5px solid var(--fg-mute);
  transform: translateY(-70%) rotate(45deg);
  pointer-events: none;
}
select {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  /* Distinctly lighter than the surrounding panel + specs block so the
     dropdown reads as an interactive control, not flat page chrome. */
  background: #1c1c24;
  color: var(--fg-bright);
  border: 1px solid #353541;
  border-radius: var(--r-md);
  padding: 12px 36px 12px 14px;
  font: inherit;
  font-size: 14px;
  cursor: pointer;
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.02) inset,
              0 1px 2px rgba(0, 0, 0, 0.4);
  transition: background 120ms ease, border-color 120ms ease;
}
select:hover {
  background: #20202a;
  border-color: #44444f;
}
select:focus {
  outline: none;
  border-color: var(--accent-line);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

/* ────────── specs ────────── */

.specs {
  margin: 0 0 20px;
  max-width: 560px;
  padding: 14px 16px;
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.spec-row {
  display: grid;
  grid-template-columns: 92px 1fr;
  gap: 16px;
  align-items: baseline;
  font-family: var(--mono);
  font-size: 13px;
}
.spec-row dt {
  color: var(--fg-dim);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  text-transform: lowercase;
}
.spec-row dd {
  margin: 0;
  color: var(--fg-bright);
  word-break: break-word;
}

.status-line {
  margin: 0 0 14px;
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--fg-dim);
  min-height: 1em;
  max-width: 560px;
}
.status-line.error { color: var(--err); }
.status-line.warn  { color: var(--warn); }
.status-line:empty { display: none; }

/* ────────── install row ────────── */

.install-row {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
#install-slot {
  --esp-tools-button-color: var(--accent);
  --esp-tools-button-text-color: var(--accent-fg);
  display: flex;
  align-items: center;
  min-height: 44px;
}
#install-slot esp-web-install-button { display: inline-block; }

.hint {
  color: var(--fg-dim);
  font-size: 13px;
  margin: 0;
  text-wrap: pretty;
  max-width: 68ch;
}
.unsupported {
  color: var(--err);
  font-size: 13px;
  font-family: var(--mono);
}

/* ────────── checklist ────────── */

.checklist {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.checklist li {
  position: relative;
  padding-left: 22px;
  max-width: 72ch;
  font-size: 14.5px;
  color: var(--fg-mute);
  text-wrap: pretty;
}
.checklist li::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: var(--fg-faint);
}
.checklist li strong {
  color: var(--fg-bright);
  font-weight: 600;
  margin-right: 4px;
}

/* ────────── after-flash paths ────────── */

.path {
  margin: 0 0 4px;
}
.path-head {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}
.path-head h3 {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--fg-bright);
  letter-spacing: -0.005em;
}
.path-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid var(--accent-line);
  border-radius: 999px;
}
.path-tag-muted {
  color: var(--fg-dim);
  background: var(--bg-elev-1);
  border-color: var(--border);
}
.path-timer {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: auto;
  padding: 3px 9px;
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.04em;
  color: var(--fg-dim);
  background: var(--bg-inset);
  border: 1px solid var(--border);
  border-radius: 999px;
}
.path-timer-dot {
  width: 6px;
  height: 6px;
  border-radius: 999px;
  border: 1.5px solid var(--fg-dim);
  border-top-color: transparent;
}
.path-pulse {
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: var(--accent);
  box-shadow: 0 0 0 0 var(--accent-line);
  animation: path-pulse 1.8s ease-out infinite;
}
@keyframes path-pulse {
  0%   { box-shadow: 0 0 0 0 rgba(34, 211, 238, 0.45); }
  100% { box-shadow: 0 0 0 8px rgba(34, 211, 238, 0); }
}
@media (prefers-reduced-motion: reduce) {
  .path-pulse { animation: none; }
}

.path-body {
  margin: 0 0 14px;
  max-width: 68ch;
  color: var(--fg-mute);
  font-size: 14.5px;
  text-wrap: pretty;
}
.path-body strong { color: var(--fg-bright); font-weight: 500; }
.path-body a { color: var(--fg-bright); }

.path-divider {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 24px 0;
  color: var(--fg-faint);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  max-width: 640px;
}
.path-divider::before,
.path-divider::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border-soft);
}

/* ────────── credentials block ────────── */

.creds {
  margin: 0 0 22px;
  max-width: 560px;
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  overflow: hidden;
}
.creds-head {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-inset);
}
.creds-dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent-line);
}
.creds-title {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--fg-dim);
  letter-spacing: 0.04em;
  text-transform: lowercase;
}
.creds-row {
  display: grid;
  grid-template-columns: 92px 1fr;
  gap: 16px;
  align-items: baseline;
  padding: 11px 16px;
  font-family: var(--mono);
  font-size: 14px;
  border-bottom: 1px dashed var(--border);
}
.creds-row:last-of-type { border-bottom: 0; }
.creds-key {
  color: var(--fg-dim);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  text-transform: lowercase;
}
.creds-val {
  color: var(--fg-bright);
  word-break: break-all;
}
.creds-val .dim { color: var(--fg-faint); }
.creds-val a { color: var(--accent); border-bottom: 1px dotted var(--accent-line); }
.creds-val a:hover { border-bottom-color: var(--accent); }

.creds-note {
  margin: 0;
  padding: 8px 16px 12px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-faint);
  background: var(--bg-inset);
  border-top: 1px solid var(--border);
}

/* ────────── step list ────────── */

.step-list {
  counter-reset: step;
  list-style: none;
  padding: 0;
  margin: 0 0 18px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.step-list li {
  counter-increment: step;
  position: relative;
  padding-left: 34px;
  min-height: 22px;
  max-width: 72ch;
  font-size: 14.5px;
  color: var(--fg-mute);
  text-wrap: pretty;
}
.step-list li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-dim);
  background: var(--bg-elev-1);
  border: 1px solid var(--border);
  border-radius: 6px;
  width: 22px;
  height: 22px;
  display: inline-grid;
  place-items: center;
}

/* ────────── links ────────── */

a {
  color: var(--fg-bright);
  text-decoration: none;
  border-bottom: 1px solid var(--border-strong);
  transition: border-color 120ms ease, color 120ms ease;
}
a:hover { border-color: var(--accent); color: var(--accent); }

/* ────────── footer ────────── */

.footer {
  margin-top: 40px;
  padding-top: 22px;
  border-top: 1px solid var(--border-soft);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  color: var(--fg-dim);
  font-family: var(--mono);
  font-size: 11.5px;
  flex-wrap: wrap;
}
.footer a {
  color: var(--fg-mute);
  border-bottom: 0;
}
.footer a:hover { color: var(--fg-bright); }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

esp-web-install-button::part(button) {
  font-family: var(--sans) !important;
}

/* ────────── responsive ────────── */

@media (max-width: 980px) {
  :root { --rail-gap: 48px; --rail-width: 200px; }
  .shell { padding: 28px 36px 60px; }
  .hero h1 { font-size: 40px; }
}

@media (max-width: 820px) {
  .shell { padding: 24px 24px 48px; }
  .layout {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .rail {
    position: static;
    max-height: none;
    overflow: visible;
    padding-right: 0;
    padding-bottom: 18px;
    border-bottom: 1px solid var(--border-soft);
  }
  .rail-inner {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 16px 24px;
    align-items: center;
  }
  .toc, .rail-foot { display: none; }
  .rail-links {
    flex-direction: row;
    gap: 16px;
    grid-column: 1 / -1;
  }
  .rail-links .rail-label { display: none; }
  .hero h1 { font-size: 32px; }
}

@media (max-width: 480px) {
  .spec-row, .creds-row { grid-template-columns: 76px 1fr; gap: 12px; }
  .hero h1 { font-size: 26px; }
}