/* SPDX-License-Identifier: MIT */
/* Dark oscilloscope theme */

:root {
  --bg:        #0d1117;
  --surface:   #161b22;
  --border:    #30363d;
  --text:      #e6edf3;
  --muted:     #8b949e;
  --accent:    #58a6ff;
  --green:     #3fb950;
  --amber:     #d29922;
  --red:       #f85149;
  --mono-font: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  --sans-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans-font);
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Layout ───────────────────────────────────────────────────── */

header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  position: sticky;
  top: 0;
  z-index: 100;
}

header h1 {
  font-size: 18px;
  font-weight: 600;
  font-family: var(--mono-font);
  color: var(--accent);
}

nav { display: flex; gap: 4px; }

nav a {
  color: var(--muted);
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 15px;
  transition: color 0.15s, background 0.15s;
}

nav a:hover, nav a.active {
  color: var(--text);
  background: var(--border);
  text-decoration: none;
}

nav a.active { color: var(--accent); }

main { max-width: 900px; margin: 0 auto; padding: 32px 24px; }

footer {
  text-align: center;
  padding: 24px;
  color: var(--muted);
  font-size: 13px;
  border-top: 1px solid var(--border);
  margin-top: 48px;
}

/* ── Tabs ─────────────────────────────────────────────────────── */

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── Step cards ───────────────────────────────────────────────── */

.step-list { display: flex; flex-direction: column; gap: 12px; }

.step-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  transition: border-color 0.2s;
}

.step-card.active { border-color: var(--accent); }

.step-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  cursor: default;
}

.step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-family: var(--mono-font);
  flex-shrink: 0;
}

.step-card.active .step-num { background: var(--accent); color: var(--bg); }
.step-card.done .step-num { background: var(--green); color: var(--bg); }

.step-title { font-weight: 600; flex: 1; }
.step-badge { font-size: 13px; color: var(--muted); font-family: var(--mono-font); }

.step-body {
  padding: 0 16px 16px;
  display: none;
  border-top: 1px solid var(--border);
}

.step-card.active .step-body,
.step-card.done .step-body { display: block; }

.step-desc {
  color: var(--text);
  font-size: 15px;
  margin: 12px 0 16px;
  line-height: 1.65;
}

/* ── Form elements ────────────────────────────────────────────── */

.input-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
  align-items: flex-end;
}

label {
  display: block;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 4px;
  font-family: var(--mono-font);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

input[type="text"], textarea, select {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-family: var(--mono-font);
  font-size: 14px;
  padding: 8px 10px;
  outline: none;
  transition: border-color 0.15s;
}

input[type="text"]:focus, textarea:focus, select:focus {
  border-color: var(--accent);
}

textarea { resize: vertical; min-height: 80px; width: 100%; }

.input-error {
  color: var(--red);
  font-size: 12px;
  margin-top: 4px;
  font-family: var(--mono-font);
  display: none;
}

.input-error.visible { display: block; }

input[aria-invalid="true"] { border-color: var(--red); }

/* ── Buttons ──────────────────────────────────────────────────── */

button {
  background: var(--accent);
  color: var(--bg);
  border: none;
  border-radius: 6px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s;
}

button:hover { opacity: 0.85; }
button:disabled { opacity: 0.4; cursor: not-allowed; }
button.secondary { background: var(--border); color: var(--text); }
button.danger { background: var(--red); }

/* ── Canvas & visualization ───────────────────────────────────── */

canvas {
  display: block;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  max-width: 100%;
}

.canvas-wrap { margin: 12px 0; }
.canvas-wrap figcaption {
  font-size: 13px;
  color: var(--muted);
  margin-top: 6px;
  font-family: var(--mono-font);
}

/* ── Bit/symbol tables ────────────────────────────────────────── */

.bit-label {
  font-family: var(--mono-font);
  font-size: 13px;
  padding: 2px 6px;
  border-radius: 4px;
  display: inline-block;
  margin: 2px;
}

.mono { font-family: var(--mono-font); }

.field-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 8px 0;
}

.field-swatch {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-family: var(--mono-font);
}

.swatch-dot {
  width: 10px; height: 10px;
  border-radius: 2px;
  flex-shrink: 0;
}

/* ── Result/output boxes ──────────────────────────────────────── */

.result-box {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px 16px;
  font-family: var(--mono-font);
  font-size: 14px;
  margin: 8px 0;
  white-space: pre-wrap;
  word-break: break-all;
}

.terminal-box {
  background: #000;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 24px;
  font-family: var(--mono-font);
  font-size: 20px;
  color: var(--green);
  margin: 12px 0;
  box-shadow: 0 0 20px rgba(63, 185, 80, 0.1);
}

/* ── Status badges ────────────────────────────────────────────── */

.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 12px;
  font-size: 12px;
  font-weight: 600;
  font-family: var(--mono-font);
}

.badge-green { background: rgba(63,185,80,.2); color: var(--green); border: 1px solid rgba(63,185,80,.4); }
.badge-red { background: rgba(248,81,73,.2); color: var(--red); border: 1px solid rgba(248,81,73,.4); }
.badge-amber { background: rgba(210,153,34,.2); color: var(--amber); border: 1px solid rgba(210,153,34,.4); }
.badge-blue { background: rgba(88,166,255,.2); color: var(--accent); border: 1px solid rgba(88,166,255,.4); }

/* ── Collapsible tables ───────────────────────────────────────── */

.collapse-toggle {
  background: none;
  border: 1px solid var(--border);
  color: var(--accent);
  font-size: 12px;
  padding: 4px 10px;
  margin-top: 8px;
  border-radius: 4px;
  cursor: pointer;
}

.collapse-toggle:hover { background: var(--border); opacity: 1; }

.collapsible { overflow: hidden; }
.collapsible.collapsed { display: none; }

/* ── Progress bar ─────────────────────────────────────────────── */

.progress-wrap {
  background: var(--border);
  border-radius: 4px;
  height: 6px;
  margin: 8px 0;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: var(--accent);
  border-radius: 4px;
  transition: width 0.1s linear;
  width: 0%;
}

/* ── SNR slider ───────────────────────────────────────────────── */

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

/* ── About page ───────────────────────────────────────────────── */

.pipeline-diagram {
  font-family: var(--mono-font);
  font-size: 13px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 24px;
  line-height: 2;
  color: var(--muted);
  margin: 16px 0;
}

.pipeline-diagram .highlight { color: var(--accent); }

h2 { font-size: 22px; margin-bottom: 12px; font-weight: 600; }
h3 { font-size: 16px; margin: 20px 0 8px; font-weight: 600; color: var(--text); }

p { color: var(--text); margin-bottom: 12px; }
p strong { color: var(--text); }

.const-table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 13px; }
.const-table th { text-align: left; padding: 6px 12px; color: var(--muted); border-bottom: 1px solid var(--border); }
.const-table td { padding: 6px 12px; font-family: var(--mono-font); border-bottom: 1px solid rgba(48,54,61,.5); }

/* ── Loading overlay ──────────────────────────────────────────── */

#loading {
  position: fixed; inset: 0;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  z-index: 999;
  transition: opacity 0.3s;
}

#loading.hidden { opacity: 0; pointer-events: none; }

.spinner {
  width: 40px; height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

#loading p { color: var(--muted); font-family: var(--mono-font); font-size: 14px; }

/* ── Utility ────────────────────────────────────────────────────── */
.hidden { display: none; }
.mt-8  { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mb-12 { margin-bottom: 12px; }
.my-8  { margin: 8px 0; }
.my-12 { margin: 12px 0; }
.text-muted { color: var(--muted); }
.result-box-sm { font-size: 12px; }

/* ── Field legend swatch colors ─────────────────────────────────── */
.swatch-blue   { background: #58a6ff; }
.swatch-green  { background: #3fb950; }
.swatch-amber  { background: #d29922; }
.swatch-purple { background: #bc8cff; }
.swatch-border { background: #30363d; }
.swatch-muted  { background: #8b949e; }
.swatch-red    { background: #f85149; }
.swatch-ltblue { background: #79c0ff; }
.swatch-ltgreen { background: #39d353; }

/* ── Tone colors (Gray code 8-FSK, tone 0–7) ────────────────────── */
.tone-0 { background: #58a6ff; }
.tone-1 { background: #3fb950; }
.tone-2 { background: #d29922; }
.tone-3 { background: #f85149; }
.tone-4 { background: #bc8cff; }
.tone-5 { background: #39d353; }
.tone-6 { background: #ff7b72; }
.tone-7 { background: #79c0ff; }

/* ── Tone swatch cell ────────────────────────────────────────────── */
.tone-swatch {
  width: 14px; height: 14px;
  border-radius: 3px;
  display: inline-block;
}

/* ── Gray code table ─────────────────────────────────────────────── */
.gray-code-table {
  border-collapse: collapse;
  font-size: 12px;
  font-family: var(--mono-font);
  width: 100%;
}
.gray-code-table thead tr {
  color: var(--muted);
  border-bottom: 1px solid var(--border);
}
.gray-code-table th { padding: 4px 8px; text-align: left; }
.gray-code-table th.th-empty { padding: 4px 8px; text-align: left; }
.gray-code-table td { padding: 3px 8px; }

/* ── Play controls row ───────────────────────────────────────────── */
.play-controls {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 12px;
}