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

:root {
  --bg: #0a0a0f;
  --bg-panel: #0d0d14;
  --border: #1a1a2e;
  --cyan: #00f0ff;
  --magenta: #ff00aa;
  --green: #39ff14;
  --text: #e0e0ee;
  --text-dim: #8888a8;
  --glow-cyan: 0 0 10px rgba(0, 240, 255, 0.3), 0 0 40px rgba(0, 240, 255, 0.1);
  --glow-magenta: 0 0 10px rgba(255, 0, 170, 0.3), 0 0 40px rgba(255, 0, 170, 0.1);
  --glow-green: 0 0 10px rgba(57, 255, 20, 0.3), 0 0 40px rgba(57, 255, 20, 0.1);
  --mono: 'Courier New', 'Consolas', monospace;
  --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 60px 20px;
  overflow-x: hidden;
}

.scanlines {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1000;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0, 0, 0, 0.03) 2px,
    rgba(0, 0, 0, 0.03) 4px
  );
}

.container {
  max-width: 720px;
  width: 100%;
}

.title {
  font-family: var(--mono);
  font-size: 2.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.title-sentence {
  color: var(--green);
  text-shadow: var(--glow-green);
}

.title-accent {
  color: var(--magenta);
  text-shadow: var(--glow-magenta);
}

.title-ipv6 {
  color: var(--cyan);
  text-shadow: var(--glow-cyan);
}

.subtitle {
  color: var(--text);
  font-size: 1.05rem;
  font-weight: 500;
  margin-bottom: 40px;
}

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  margin-bottom: 20px;
  position: relative;
}

.panel::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 20px;
  right: 20px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  opacity: 0.4;
  animation: glow-pulse 3s ease-in-out infinite;
}

.label {
  display: block;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text);
  margin-bottom: 10px;
}

.input-row {
  display: flex;
  gap: 12px;
}

.input-field {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 14px 16px;
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--text);
  outline: none;
  transition: border-color 0.3s, box-shadow 0.3s;
}

.input-field:focus {
  border-color: var(--cyan);
  box-shadow: var(--glow-cyan);
}

.input-field::placeholder {
  color: var(--text-dim);
  opacity: 0.7;
}

.input-field--sentence {
  font-family: var(--sans);
}

.convert-btn {
  background: transparent;
  border: 1px solid var(--cyan);
  border-radius: 6px;
  padding: 14px 24px;
  font-family: var(--mono);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--cyan);
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  transition: all 0.3s;
}

.convert-btn:hover {
  background: rgba(0, 240, 255, 0.1);
  box-shadow: var(--glow-cyan);
}

.output-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.output-row:last-child {
  margin-bottom: 0;
}

.ip-display {
  font-family: var(--mono);
  font-size: 1.1rem;
  color: var(--cyan);
  text-shadow: var(--glow-cyan);
  word-break: break-all;
  flex: 1;
}

.sentence-display {
  font-family: var(--sans);
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--green);
  text-shadow: var(--glow-green);
  line-height: 1.6;
  flex: 1;
}

.copy-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 6px 10px;
  color: var(--text-dim);
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.2s;
  flex-shrink: 0;
}

.copy-btn:hover {
  border-color: var(--magenta);
  color: var(--magenta);
}

.result-inline {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 12px;
  padding: 14px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  flex-wrap: wrap;
}

.result-inline--short {
  margin-top: 8px;
}

.result-label {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  min-width: 40px;
}

.error {
  color: var(--magenta);
  font-family: var(--mono);
  font-size: 0.95rem;
  text-shadow: var(--glow-magenta);
  padding: 12px 0;
}

@keyframes glow-pulse {
  0%, 100% { opacity: 0.4; }
  50% { opacity: 0.8; }
}

@media (max-width: 600px) {
  .title { font-size: 1.6rem; }
  .input-row { flex-direction: column; }
  .convert-btn { width: 100%; }
  body { padding: 30px 16px; }
}