:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #14141f;
  --bg-tertiary: #1e1e2e;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  --accent: #00d4ff;
  --accent-secondary: #00ff88;
  --danger: #ff4466;
  --focus-ring: #00d4ff;
  --focus-glow: rgba(0, 212, 255, 0.4);
  --radius-md: 12px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body {
  width: 600px; height: 600px; overflow: hidden;
  background: #000;
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}
#app { width: 100%; height: 100%; position: relative; }
.screen { width: 100%; height: 100%; position: absolute; top: 0; left: 0; display: flex; flex-direction: column; }
.screen.hidden { display: none; }
.focusable { transition: all 0.15s ease; border: 2px solid transparent; cursor: pointer; outline: none; }
.focusable:focus { border-color: var(--focus-ring); box-shadow: 0 0 20px var(--focus-glow); }
.hidden { display: none !important; }

/* ---- header ---- */
.hdr { padding: 12px 18px 8px; }
.hdr h1 { font-size: 26px; font-weight: 700; letter-spacing: 0.5px; }
.hdr .sub { color: var(--text-secondary); font-size: 14px; margin-top: 2px; }
.hdr.bar { display: flex; align-items: center; gap: 12px; padding: 12px 16px; border-bottom: 1px solid var(--bg-tertiary); }
.hdr.bar h2 { font-size: 22px; font-weight: 600; }
.back {
  width: 48px; height: 48px; flex: 0 0 48px;
  background: var(--bg-secondary); color: var(--text-primary);
  border-radius: var(--radius-md); font-size: 30px; line-height: 1;
}

/* ---- output panel ---- */
.out {
  margin: 4px 16px 0; padding: 6px 0;
  display: flex; flex-direction: column; gap: 6px;
}
.orow {
  display: flex; align-items: center; gap: 12px;
  background: var(--bg-secondary);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  padding: 8px 14px; min-height: 44px;
}
.orow.active { border-color: var(--accent); background: var(--bg-tertiary); }
.olbl {
  flex: 0 0 44px; font-size: 13px; font-weight: 700;
  color: var(--accent); letter-spacing: 1px;
}
.oval {
  font-family: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 22px; font-weight: 600; word-break: break-all;
}
.orow.active .oval { color: var(--accent); }
.mono-bin { font-size: 14px; line-height: 1.35; letter-spacing: 0.5px; color: var(--text-secondary); }
.orow.active .mono-bin { color: var(--accent); }

.note {
  text-align: center; color: var(--text-muted);
  font-size: 13px; padding: 6px 16px 2px;
}
.note.warn { color: var(--danger); }

/* ---- base tabs ---- */
.tabs {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 8px; padding: 4px 16px 8px;
}
.tab {
  height: 48px; border-radius: var(--radius-md);
  background: var(--bg-secondary); color: var(--text-secondary);
  font-size: 16px; font-weight: 700; letter-spacing: 1px;
}
.tab.sel { background: var(--accent); color: #001018; border-color: var(--accent); }

/* ---- keypad ---- */
.keypad {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 8px; padding: 0 16px;
}
.key {
  height: 50px; border-radius: var(--radius-md);
  background: var(--bg-tertiary); color: var(--text-primary);
  font-family: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 22px; font-weight: 600;
}
.key.disabled {
  background: #0c0c12; color: var(--text-muted);
  pointer-events: none; opacity: 0.45;
}

/* ---- action row ---- */
.row-actions {
  display: flex; gap: 8px; padding: 10px 16px 12px;
  margin-top: auto;
}
.minor {
  flex: 1; height: 48px; border-radius: var(--radius-md);
  background: var(--bg-secondary); color: var(--text-primary);
  font-size: 15px; font-weight: 600;
}
.minor.wide { margin: 12px 16px; flex: none; }

/* ---- bit grid ---- */
.bit-readout {
  display: flex; gap: 10px; padding: 12px 16px 6px;
}
.bm {
  flex: 1; background: var(--bg-secondary); border-radius: var(--radius-md);
  padding: 8px 12px; display: flex; flex-direction: column; gap: 2px;
}
.bk { font-size: 12px; font-weight: 700; color: var(--accent); letter-spacing: 1px; }
.bv {
  font-family: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 20px; font-weight: 600; word-break: break-all;
}
.bit-grid {
  display: grid; grid-template-columns: repeat(8, 1fr);
  gap: 6px; padding: 8px 16px;
}
.bit {
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  height: 56px; border-radius: 10px;
  background: var(--bg-tertiary); color: var(--text-muted);
  font-family: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, monospace;
}
.bit .bval { font-size: 22px; font-weight: 700; line-height: 1; }
.bit .bidx { font-size: 10px; color: var(--text-muted); margin-top: 3px; }
.bit.on { background: var(--accent); color: #001018; }
.bit.on .bidx { color: #00465c; }

/* ---- reference ---- */
.ref-wrap { flex: 1; overflow: hidden; padding: 12px 16px; }
.ref {
  width: 100%; border-collapse: collapse;
  font-family: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, monospace;
}
.ref th {
  text-align: left; color: var(--accent); font-size: 14px;
  padding: 6px 8px; border-bottom: 2px solid var(--bg-tertiary);
}
.ref td {
  padding: 5px 8px; font-size: 15px; color: var(--text-primary);
  border-bottom: 1px solid var(--bg-secondary);
}
.ref td.b { color: var(--text-secondary); }