:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --surface2: #242836;
  --border: #2e3345;
  --text: #e8eaed;
  --text-muted: #9aa0b4;
  --accent: #6c8cff;
  --accent-hover: #8aa4ff;
  --success: #4ade80;
  --error: #f87171;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,.35);
}

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

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

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: .75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent), #a78bfa);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

nav { display: flex; gap: .5rem; flex-wrap: wrap; }

nav a {
  padding: .4rem .85rem;
  border-radius: 8px;
  color: var(--text-muted);
  font-size: .9rem;
  transition: all .2s;
}

nav a:hover, nav a.active {
  background: var(--surface2);
  color: var(--text);
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

.hero {
  text-align: center;
  padding: 3rem 1rem 2rem;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: .75rem;
  background: linear-gradient(135deg, var(--text) 30%, var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto;
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
}

.tool-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  cursor: pointer;
  transition: all .25s;
  text-decoration: none;
  color: inherit;
  display: block;
}

.tool-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.tool-card .icon {
  font-size: 2rem;
  margin-bottom: .75rem;
}

.tool-card h3 {
  font-size: 1.1rem;
  margin-bottom: .4rem;
}

.tool-card p {
  color: var(--text-muted);
  font-size: .875rem;
}

.tool-page { display: none; }
.tool-page.active { display: block; }

.tool-header {
  margin-bottom: 1.5rem;
}

.tool-header h2 {
  font-size: 1.75rem;
  margin-bottom: .5rem;
}

.tool-header p { color: var(--text-muted); }

.back-btn {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  color: var(--text-muted);
  font-size: .9rem;
  margin-bottom: 1rem;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
  font-family: inherit;
}

.back-btn:hover { color: var(--accent); }

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

.panel label {
  display: block;
  font-size: .85rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: .5rem;
  text-transform: uppercase;
  letter-spacing: .05em;
}

textarea, input[type="text"], input[type="number"] {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  padding: .75rem 1rem;
  font-family: 'SF Mono', 'Fira Code', monospace;
  font-size: .9rem;
  resize: vertical;
  transition: border-color .2s;
}

textarea { min-height: 160px; }

textarea:focus, input:focus {
  outline: none;
  border-color: var(--accent);
}

.btn-row {
  display: flex;
  gap: .75rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

button, .btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: .6rem 1.25rem;
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .2s;
  font-family: inherit;
}

button:hover, .btn:hover { background: var(--accent-hover); }

button.secondary {
  background: var(--surface2);
  color: var(--text);
  border: 1px solid var(--border);
}

button.secondary:hover { background: var(--border); }

.output {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  font-family: 'SF Mono', 'Fira Code', monospace;
  font-size: .875rem;
  white-space: pre-wrap;
  word-break: break-all;
  min-height: 80px;
  margin-top: .75rem;
}

.output.error { border-color: var(--error); color: var(--error); }
.output.success { border-color: var(--success); }

.options-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
  margin: .75rem 0;
}

.options-row label.inline {
  display: flex;
  align-items: center;
  gap: .4rem;
  text-transform: none;
  font-weight: 400;
  color: var(--text);
  margin: 0;
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

@media (max-width: 768px) {
  .split { grid-template-columns: 1fr; }
  .hero h1 { font-size: 1.75rem; }
  header { padding: 1rem; }
  main { padding: 1rem; }
}

footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: .85rem;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--surface2);
  border: 1px solid var(--border);
  padding: .75rem 1.25rem;
  border-radius: 8px;
  font-size: .9rem;
  opacity: 0;
  transform: translateY(10px);
  transition: all .3s;
  z-index: 1000;
}

.toast.show { opacity: 1; transform: translateY(0); }