:root {
  --bg: #f5f5f7;
  --surface: #ffffff;
  --surface2: #f0f0f5;
  --border: #d1d1d6;
  --text: #1d1d1f;
  --text2: #6e6e73;
  --accent: #0071e3;
  --accent2: #ff6b35;
  --success: #34c759;
  --error: #ff3b30;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --radius: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1c1c1e;
    --surface: #2c2c2e;
    --surface2: #3a3a3c;
    --border: #3a3a3c;
    --text: #f2f2f7;
    --text2: #98989d;
    --accent: #0a84ff;
    --accent2: #ff9f0a;
    --shadow: 0 2px 12px rgba(0,0,0,0.4);
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 24px 32px;
}

header h1 {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

header p { color: var(--text2); margin-top: 4px; }

header .badge {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 20px;
  margin-left: 10px;
  vertical-align: middle;
  letter-spacing: 0.04em;
}

main {
  max-width: 860px;
  margin: 0 auto;
  padding: 24px 16px 48px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}

.card h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.card .description {
  color: var(--text2);
  font-size: 0.9rem;
  margin-bottom: 16px;
  line-height: 1.5;
}

/* Sample buttons */
.sample-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.sample-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.82rem;
  padding: 6px 14px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.sample-btn:hover { background: var(--border); border-color: var(--accent); }

/* Textarea */
#input-text {
  width: 100%;
  height: 160px;
  padding: 12px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: "SF Mono", "Fira Code", monospace;
  font-size: 0.85rem;
  resize: vertical;
  outline: none;
  transition: border-color 0.15s;
}

#input-text:focus { border-color: var(--accent); }

/* File upload */
.file-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 12px;
}

.file-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.85rem;
  padding: 7px 14px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s;
}

.file-label:hover { background: var(--border); }
.file-label input[type="file"] { display: none; }
#file-name { font-size: 0.82rem; color: var(--text2); }

/* Controls */
.controls-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.controls-row label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text2);
}

select {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.9rem;
  padding: 7px 10px;
  border-radius: 8px;
  outline: none;
  cursor: pointer;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: opacity 0.15s, transform 0.1s;
}

.btn:hover:not(:disabled) { opacity: 0.88; transform: translateY(-1px); }
.btn:active:not(:disabled) { transform: translateY(0); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-primary { background: var(--accent); color: #fff; }
.btn-secondary { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }

/* Stats grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 12px;
  margin-bottom: 20px;
}

.stat-box {
  background: var(--surface2);
  border-radius: 10px;
  padding: 14px 16px;
}

.stat-box .label {
  font-size: 0.75rem;
  color: var(--text2);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 4px;
}

.stat-box .value {
  font-size: 1.3rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.stat-box.ratio .value { color: var(--success); }
.stat-box.time .value { color: var(--accent); }

/* Compression ratio visual bar */
.ratio-bar-wrap { margin-bottom: 20px; }
.ratio-bar-wrap .bar-label {
  font-size: 0.82rem;
  color: var(--text2);
  margin-bottom: 6px;
}

.ratio-bar-track {
  height: 8px;
  background: var(--surface2);
  border-radius: 4px;
  overflow: hidden;
}

.ratio-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--success), var(--accent));
  border-radius: 4px;
  transition: width 0.4s ease;
}

/* Hex preview */
.hex-section h3 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text2);
}

#hex-dump {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  font-family: "SF Mono", "Fira Code", monospace;
  font-size: 0.78rem;
  line-height: 1.8;
  overflow-x: auto;
  color: var(--accent);
  white-space: pre;
}

/* Benchmark */
#bench-btn { margin-bottom: 16px; }

.bench-progress {
  height: 4px;
  background: var(--surface2);
  border-radius: 2px;
  margin-bottom: 16px;
  overflow: hidden;
}

.bench-progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.3s;
}

#bench-chart {
  display: block;
  width: 100%;
  max-width: 700px;
  height: auto;
  margin-bottom: 20px;
  border-radius: 8px;
}

#bench-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

#bench-table th {
  text-align: left;
  padding: 8px 12px;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text2);
  border-bottom: 1px solid var(--border);
}

#bench-table td {
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
}

#bench-table tr:last-child td { border-bottom: none; }
#bench-table tr:hover td { background: var(--surface2); }

.level-fast { color: var(--success); font-weight: 600; }
.level-hc { color: var(--accent2); }

/* Loading overlay */
#loading {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  color: var(--text2);
  z-index: 100;
}

#loading::after {
  content: "";
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  margin-left: 12px;
  animation: spin 0.7s linear infinite;
}

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

/* Status bar */
#status-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 8px 24px;
  font-size: 0.82rem;
  background: var(--surface);
  border-top: 1px solid var(--border);
  color: var(--text2);
  z-index: 50;
}

.hidden { display: none !important; }

/* Responsive */
@media (max-width: 600px) {
  header { padding: 16px; }
  main { padding: 12px 8px 64px; gap: 12px; }
  .card { padding: 16px; }
  header h1 { font-size: 1.4rem; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}