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

:root {
  --pcb-dark: #0a1a0a;
  --pcb-green: #1a3a1a;
  --pcb-light: #1e4a1e;
  --copper: #c8a84e;
  --copper-dim: #8a6d2b;
  --led-red: #ff2200;
  --led-red-dim: #331000;
  --led-red-glow: rgba(255, 34, 0, 0.6);
  --phosphor: #33ff33;
  --phosphor-dim: #0a3a0a;
  --btn-tan: #c8b080;
  --btn-tan-dark: #9a7a50;
  --btn-red: #cc3333;
  --text-light: #e0d8c0;
  --text-dim: #6a6a5a;
  --panel-bg: #0d1a0d;
  --panel-border: #2a4a2a;
}

body {
  background: var(--pcb-dark);
  color: var(--text-light);
  font-family: 'IBM Plex Mono', monospace;
  min-height: 100vh;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background:
    repeating-linear-gradient(0deg, transparent, transparent 2px, rgba(0,255,0,0.01) 2px, rgba(0,255,0,0.01) 4px),
    radial-gradient(ellipse at 50% 30%, rgba(26,58,26,0.4) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

#root { position: relative; z-index: 1; }

/* Header */
.header {
  background: linear-gradient(180deg, var(--pcb-green) 0%, var(--pcb-dark) 100%);
  border-bottom: 2px solid var(--copper);
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

.header-title {
  font-family: 'VT323', monospace;
  font-size: 28px;
  color: var(--copper);
  letter-spacing: 3px;
  text-shadow: 0 0 10px rgba(200, 168, 78, 0.3);
}

.header-subtitle {
  font-size: 11px;
  color: var(--text-dim);
  letter-spacing: 1px;
}

.status-led {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-right: 6px;
  vertical-align: middle;
}

.status-led.stopped { background: #ff2200; box-shadow: 0 0 6px #ff2200; }
.status-led.running { background: #33ff33; box-shadow: 0 0 6px #33ff33; animation: led-blink 1s ease infinite; }
.status-led.waiting { background: #ffcc00; box-shadow: 0 0 6px #ffcc00; animation: led-blink 0.5s ease infinite; }

@keyframes led-blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

/* Main Layout */
.main-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 16px;
  padding: 16px;
  max-width: 1400px;
  margin: 0 auto;
}

@media (max-width: 900px) {
  .main-layout {
    grid-template-columns: 1fr;
  }
}

/* Panel */
.panel {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 6px;
  overflow: hidden;
}

.panel-header {
  background: linear-gradient(180deg, var(--pcb-green), var(--pcb-dark));
  border-bottom: 1px solid var(--copper-dim);
  padding: 8px 12px;
  font-size: 12px;
  color: var(--copper);
  letter-spacing: 1px;
  font-weight: 600;
  cursor: pointer;
  user-select: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.panel-body { padding: 12px; }

/* ROM Upload */
.rom-dropzone {
  border: 2px dashed var(--copper-dim);
  border-radius: 6px;
  padding: 24px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  background: rgba(200, 168, 78, 0.03);
}

.rom-dropzone:hover, .rom-dropzone.dragover {
  border-color: var(--copper);
  background: rgba(200, 168, 78, 0.08);
}

.rom-status-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 0;
  font-size: 13px;
}

.rom-status-item .check { color: var(--phosphor); }
.rom-status-item .uncheck { color: var(--text-dim); }

/* Seven Segment Display */
.display-container {
  background: #0a0a0a;
  border: 2px solid #333;
  border-radius: 8px;
  padding: 16px 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  box-shadow: inset 0 2px 8px rgba(0,0,0,0.8);
  position: relative;
}

.display-separator {
  width: 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.display-separator .dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--led-red-dim);
}

.digit-wrapper {
  position: relative;
  width: 36px;
  height: 56px;
}

.segment {
  position: absolute;
  background: var(--led-red-dim);
  border-radius: 1px;
  transition: background 0.08s, box-shadow 0.08s;
}

.segment.on {
  background: var(--led-red);
  box-shadow: 0 0 8px var(--led-red-glow), 0 0 16px rgba(255,34,0,0.3);
}

/* Horizontal segments */
.seg-h { width: 22px; height: 4px; left: 7px; }
.seg-a { top: 0; }
.seg-g { top: 26px; }
.seg-d { top: 52px; }

/* Vertical segments */
.seg-v { width: 4px; height: 22px; }
.seg-b { right: 3px; top: 3px; }
.seg-c { right: 3px; top: 29px; }
.seg-e { left: 3px; top: 29px; }
.seg-f { left: 3px; top: 3px; }

/* Keypad */
.keypad {
  display: grid;
  gap: 6px;
  margin-top: 12px;
}

.keypad-main {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 6px;
}

.key-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 700;
  font-size: 14px;
  padding: 10px 4px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  background: linear-gradient(180deg, var(--btn-tan) 0%, var(--btn-tan-dark) 100%);
  color: #1a1a0a;
  box-shadow: 0 3px 0 #6a5a30, 0 4px 6px rgba(0,0,0,0.4);
  transition: all 0.05s;
  user-select: none;
  text-align: center;
  min-width: 0;
}

.key-btn:active, .key-btn.pressed {
  transform: translateY(2px);
  box-shadow: 0 1px 0 #6a5a30, 0 2px 3px rgba(0,0,0,0.4);
}

.key-btn.key-rs {
  background: linear-gradient(180deg, #dd4444, #993333);
  color: #fff;
  box-shadow: 0 3px 0 #661111, 0 4px 6px rgba(0,0,0,0.4);
}

.key-btn.key-rs:active { box-shadow: 0 1px 0 #661111, 0 2px 3px rgba(0,0,0,0.4); }

.key-btn.key-go {
  background: linear-gradient(180deg, #44aa44, #338833);
  color: #fff;
  box-shadow: 0 3px 0 #226622, 0 4px 6px rgba(0,0,0,0.4);
}

.key-special-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 6px;
  margin-top: 6px;
}

/* Control Bar */
.control-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding: 10px 12px;
  background: var(--pcb-green);
  border-bottom: 1px solid var(--copper-dim);
}

.ctrl-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  font-weight: 600;
  padding: 6px 12px;
  border: 1px solid var(--copper-dim);
  border-radius: 3px;
  cursor: pointer;
  background: var(--pcb-dark);
  color: var(--copper);
  transition: all 0.15s;
}

.ctrl-btn:hover { background: var(--pcb-green); border-color: var(--copper); }
.ctrl-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.ctrl-btn.active { background: var(--copper-dim); color: #fff; }

.speed-control {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--text-dim);
}

.speed-control input[type="range"] {
  width: 80px;
  accent-color: var(--copper);
}

/* CPU Registers */
.register-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 12px;
  font-size: 13px;
}

.reg-label {
  color: var(--copper);
  font-weight: 600;
}

.reg-value {
  font-family: 'VT323', monospace;
  font-size: 18px;
  color: var(--phosphor);
  text-shadow: 0 0 6px rgba(51,255,51,0.4);
}

.flags-display {
  display: flex;
  gap: 4px;
  margin-top: 8px;
}

.flag {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 700;
  border-radius: 3px;
  background: var(--pcb-dark);
  border: 1px solid var(--panel-border);
  color: var(--text-dim);
}

.flag.set {
  color: var(--phosphor);
  background: rgba(51,255,51,0.1);
  border-color: var(--phosphor);
  text-shadow: 0 0 6px rgba(51,255,51,0.5);
}

/* Memory Inspector */
.mem-row {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  line-height: 1.6;
  white-space: pre;
  color: var(--text-dim);
}

.mem-addr { color: var(--copper); }
.mem-ram { color: #6699cc; }
.mem-ioram { color: var(--phosphor); }
.mem-io { color: #cccc44; }
.mem-rom { color: #cc6644; }
.mem-unmapped { color: #444; }
.mem-ascii { color: #666; }

.mem-input {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  background: var(--pcb-dark);
  border: 1px solid var(--panel-border);
  color: var(--copper);
  padding: 4px 8px;
  border-radius: 3px;
  width: 80px;
}

.mem-input:focus { border-color: var(--copper); outline: none; }

/* TTY Terminal */
.tty-output {
  background: #0a0a0a;
  border: 1px solid #222;
  border-radius: 4px;
  padding: 8px;
  font-family: 'VT323', monospace;
  font-size: 16px;
  color: var(--phosphor);
  height: 120px;
  overflow-y: auto;
  white-space: pre-wrap;
  word-break: break-all;
  text-shadow: 0 0 4px rgba(51,255,51,0.3);
  position: relative;
}

.tty-output.crt::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: repeating-linear-gradient(
    transparent 0px, transparent 2px,
    rgba(0,0,0,0.15) 2px, rgba(0,0,0,0.15) 4px
  );
  pointer-events: none;
}

.tty-input {
  font-family: 'VT323', monospace;
  font-size: 16px;
  background: #0a0a0a;
  border: 1px solid #222;
  color: var(--phosphor);
  padding: 6px 8px;
  width: 100%;
  border-radius: 4px;
  margin-top: 4px;
}

.tty-input:focus { border-color: var(--phosphor); outline: none; }

/* Program Loader */
.loader-textarea {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  background: var(--pcb-dark);
  border: 1px solid var(--panel-border);
  color: var(--text-light);
  padding: 8px;
  width: 100%;
  border-radius: 4px;
  resize: vertical;
  min-height: 60px;
}

.loader-textarea:focus { border-color: var(--copper); outline: none; }

.preset-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  padding: 4px 8px;
  background: var(--pcb-dark);
  border: 1px solid var(--panel-border);
  color: var(--copper);
  border-radius: 3px;
  cursor: pointer;
}

.preset-btn:hover { border-color: var(--copper); }

/* Help overlay */
.help-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.85);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.help-content {
  background: var(--panel-bg);
  border: 2px solid var(--copper);
  border-radius: 8px;
  padding: 24px;
  max-width: 500px;
  width: 90%;
  max-height: 80vh;
  overflow-y: auto;
  font-size: 13px;
  line-height: 1.6;
}

.help-content h2 { color: var(--copper); margin-bottom: 12px; font-family: 'VT323', monospace; font-size: 24px; }
.help-content h3 { color: var(--copper); margin: 12px 0 6px; font-size: 14px; }
.help-content kbd {
  background: var(--pcb-green);
  border: 1px solid var(--copper-dim);
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 12px;
}

/* Footer */
.footer {
  border-top: 1px solid var(--copper-dim);
  padding: 12px 20px;
  text-align: center;
  font-size: 11px;
  color: var(--text-dim);
}

.footer a {
  color: var(--copper);
  text-decoration: none;
}

.footer a:hover { text-decoration: underline; }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--pcb-dark); }
::-webkit-scrollbar-thumb { background: var(--copper-dim); border-radius: 3px; }

/* Warning */
.warning { color: #ffaa00; font-size: 11px; margin-top: 4px; }

.cycle-counter {
  font-family: 'VT323', monospace;
  font-size: 14px;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 8px;
}

.mhz-display {
  color: var(--phosphor);
  text-shadow: 0 0 4px rgba(51,255,51,0.3);
}