:root {
  --bg: #1e1e1e;
  --fg: #d4d4d4;
  --panel: #252526;
  --panel-border: #3c3c3c;
  --pane-title-bg: #1a1a1a;
  --muted: #858585;
  --border: #333;
  --btn-bg: #3c3c3c;
  --btn-hover: #4a4a4a;
  --btn-border: #555;
  --label: #9cdcfe;
  --addr: #569cd6;
  --bytes: #ce9178;
  --ok: #6a9955;
  --primary-bg: #0e639c;
  --primary-border: #1177bb;
  --primary-hover: #1177bb;
  --primary-fg: #ffffff;
  --danger-fg: #f48771;
  --danger-border: #6a3a3a;
  --danger-hover: #4a2a2a;
  --err-fg: #f48771;
  --err-bg: #2d1f1f;
  --err-border: #5a3a3a;
  --modal-backdrop: rgba(0, 0, 0, 0.55);
  --modal-shadow: 0 10px 40px rgba(0, 0, 0, 0.6);
  --kbd-bg: rgba(255, 255, 255, 0.18);
  --kbd-border: rgba(255, 255, 255, 0.25);
  color-scheme: dark;
}

body.theme-light {
  --bg: #ffffff;
  --fg: #1f1f1f;
  --panel: #f3f3f3;
  --panel-border: #d0d0d0;
  --pane-title-bg: #f6f6f6;
  --muted: #6a737d;
  --border: #d0d0d0;
  --btn-bg: #ffffff;
  --btn-hover: #f0f0f0;
  --btn-border: #c6c6c6;
  --label: #005cc5;
  --addr: #005cc5;
  --bytes: #b35900;
  --ok: #22863a;
  --primary-bg: #0366d6;
  --primary-border: #0366d6;
  --primary-hover: #0254b0;
  --primary-fg: #ffffff;
  --danger-fg: #b31d28;
  --danger-border: #f9aeb3;
  --danger-hover: #ffeef0;
  --err-fg: #b31d28;
  --err-bg: #ffeef0;
  --err-border: #f9aeb3;
  --modal-backdrop: rgba(0, 0, 0, 0.35);
  --modal-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
  --kbd-bg: rgba(0, 0, 0, 0.08);
  --kbd-border: rgba(0, 0, 0, 0.18);
  color-scheme: light;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: system-ui, -apple-system, Segoe UI, sans-serif;
  background: var(--bg);
  color: var(--fg);
}

body {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

header {
  flex: 0 0 auto;
  padding: 10px 16px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: flex-start;
  gap: 16px;
  flex-wrap: wrap;
}

header h1 {
  font-size: 16px;
  margin: 0;
  font-weight: 500;
}

header h1 .sub {
  font-size: 12px;
  color: var(--muted);
  font-weight: 400;
}

.title {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.build-time {
  font-size: 9px;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  line-height: 1;
}

.build-time:empty { display: none; }

.toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1;
  flex-wrap: wrap;
}

.toolbar label {
  font-size: 13px;
  color: var(--label);
}

.toolbar select,
.toolbar button,
.toolbar input[type="text"] {
  background: var(--btn-bg);
  color: var(--fg);
  border: 1px solid var(--btn-border);
  padding: 4px 8px;
  font-size: 13px;
  font-family: inherit;
  cursor: pointer;
}

.toolbar input[type="text"] {
  cursor: text;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
}

#filename { width: 14ch; }
#org, #stack { width: 8ch; }

.toolbar button:hover:not(:disabled) { background: var(--btn-hover); }

.toolbar button.primary {
  background: var(--primary-bg);
  border-color: var(--primary-border);
  color: var(--primary-fg);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.toolbar button.primary:hover:not(:disabled) { background: var(--primary-hover); }

.toolbar button.primary kbd {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  font-size: 11px;
  font-weight: 500;
  padding: 1px 5px;
  border-radius: 3px;
  background: var(--kbd-bg);
  border: 1px solid var(--kbd-border);
  color: var(--primary-fg);
}

.toolbar button.danger {
  color: var(--danger-fg);
  border-color: var(--danger-border);
}

.toolbar button.danger:hover:not(:disabled) { background: var(--danger-hover); }
.toolbar button:disabled { opacity: 0.4; cursor: not-allowed; }

.icon-btn {
  padding: 4px 6px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
}

.icon-btn .icon { display: block; }

/* Dark theme → show the sun (click to switch TO light);
   light theme → show the moon (click to switch TO dark). */
.icon-btn .icon-moon { display: none; }
body.theme-light .icon-btn .icon-sun { display: none; }
body.theme-light .icon-btn .icon-moon { display: block; }

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.tabs {
  flex: 0 0 auto;
  display: flex;
  gap: 1px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
  overflow-y: hidden;
  scrollbar-width: thin;
}

.tab {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  font-size: 12px;
  color: var(--muted);
  background: var(--panel);
  border-right: 1px solid var(--border);
  cursor: pointer;
  white-space: nowrap;
  user-select: none;
}

.tab:hover { color: var(--fg); }

.tab.example,
.tab.example:hover,
.tab.active.example {
  color: var(--muted);
  opacity: 0.65;
}

.tab.modified,
.tab.modified:hover,
.tab.active.modified {
  color: var(--ok);
}

.tab.active {
  background: var(--bg);
  color: var(--fg);
  border-top: 2px solid var(--primary-bg);
  padding-top: 4px;
}

.tab.active.modified { border-top-color: var(--ok); }

.tab .close {
  background: transparent;
  border: none;
  color: inherit;
  font-size: 14px;
  line-height: 1;
  padding: 0 2px;
  cursor: pointer;
  border-radius: 2px;
  opacity: 0.5;
}

.tab .close:hover { opacity: 1; background: var(--btn-hover); }

.tab-add {
  padding: 4px 12px;
  background: transparent;
  border: none;
  color: var(--muted);
  font-size: 16px;
  cursor: pointer;
  font-family: inherit;
}

.tab-add:hover { color: var(--fg); background: var(--btn-hover); }

.panes {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 7fr 3fr;
  min-height: 0;
  background: var(--bg);
}

.pane-source { grid-row: 1 / span 2; }
.pane-asm { grid-row: 1; grid-column: 2; }
.pane-bytes { grid-row: 2; grid-column: 2; }

.pane {
  display: flex;
  flex-direction: column;
  min-height: 0;
  min-width: 0;
  overflow: hidden;
}

.pane-source { border-right: 1px solid var(--border); }
.pane-asm { border-bottom: 1px solid var(--border); }

.pane-title {
  flex: 0 0 auto;
  padding: 4px 12px;
  background: var(--pane-title-bg);
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  font-size: 11px;
  border-bottom: 1px solid var(--border);
}

#source,
#asm,
#bytes {
  flex: 1;
  min-height: 0;
  padding: 8px 12px;
  margin: 0;
  border: 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  font-size: 13px;
  line-height: 18px;
  white-space: pre;
  overflow: auto;
  tab-size: 4;
  background: transparent;
  color: var(--fg);
}

#source {
  resize: none;
  outline: none;
  caret-color: var(--fg);
}

#asm, #bytes {
  user-select: text;
}

#bytes .addr { color: var(--addr); }
#bytes .byte { color: var(--bytes); }
#bytes .ascii { color: var(--muted); }

.error {
  flex: 0 0 auto;
  min-height: 28px;
  padding: 6px 12px;
  background: var(--err-bg);
  border-top: 1px solid var(--err-border);
  color: var(--err-fg);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  font-size: 12px;
  white-space: pre-wrap;
  display: none;
}

.error.visible { display: block; }

.modal[hidden] { display: none; }

.modal {
  position: fixed;
  inset: 0;
  background: var(--modal-backdrop);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.modal-panel {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 6px;
  padding: 16px 20px;
  max-width: min(80vw, 720px);
  max-height: 70vh;
  overflow: auto;
  box-shadow: var(--modal-shadow);
}

.confirm-panel { min-width: 320px; max-width: 480px; }

.confirm-panel p {
  margin: 0 0 16px;
  color: var(--fg);
  font-size: 14px;
  line-height: 1.4;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
}

.modal-actions button {
  background: var(--btn-bg);
  color: var(--fg);
  border: 1px solid var(--btn-border);
  padding: 6px 14px;
  font-size: 13px;
  font-family: inherit;
  cursor: pointer;
  border-radius: 2px;
}

.modal-actions button:hover { background: var(--btn-hover); }

.modal-actions button.primary {
  background: var(--primary-bg);
  border-color: var(--primary-border);
  color: var(--primary-fg);
}

.modal-actions button.primary:hover { background: var(--primary-hover); }