/* DevToolKit.io — Design System */
:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --bg-input: #0d1117;
  --border: #30363d;
  --border-focus: #58a6ff;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #484f58;
  --accent: #58a6ff;
  --accent-hover: #79c0ff;
  --success: #3fb950;
  --error: #f85149;
  --warning: #d29922;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --font-mono: 'SF Mono', 'Cascadia Code', 'Fira Code', 'JetBrains Mono', Consolas, monospace;
  --radius: 8px;
  --radius-sm: 4px;
  --shadow: 0 1px 3px rgba(0,0,0,.4);
  --transition: 150ms ease;
}

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

html { font-size: 16px; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* Nav */
.nav {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: .75rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
  flex-wrap: wrap;
}
.nav-logo {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}
.nav-logo span { color: var(--text-muted); }
.nav-links { display: flex; gap: .25rem; flex-wrap: wrap; }
.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  padding: .35rem .7rem;
  border-radius: var(--radius-sm);
  font-size: .85rem;
  transition: all var(--transition);
  white-space: nowrap;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

/* Layout */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}
.tool-header { margin-bottom: 1.5rem; }
.tool-header h1 {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  margin-bottom: .25rem;
}
.tool-header p { color: var(--text-secondary); font-size: .95rem; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .5rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: .85rem;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  user-select: none;
}
.btn:hover { border-color: var(--border-focus); background: var(--bg-secondary); }
.btn-primary { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 600; }
.btn-primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); }
.btn-sm { padding: .3rem .6rem; font-size: .8rem; }
.btn-group { display: flex; gap: .5rem; flex-wrap: wrap; margin: .75rem 0; }

/* Inputs & Textareas */
textarea, input[type="text"], input[type="number"], select {
  width: 100%;
  padding: .6rem .8rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: .875rem;
  line-height: 1.5;
  transition: border-color var(--transition);
  resize: vertical;
}
textarea:focus, input:focus, select:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(88,166,255,.15);
}
textarea { min-height: 180px; }
label {
  display: block;
  font-size: .85rem;
  color: var(--text-secondary);
  margin-bottom: .3rem;
  font-weight: 500;
}

/* Panels */
.panel {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: 1rem;
}
.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: .75rem;
}
.panel-header h3 { font-size: .9rem; font-family: var(--font-mono); }

/* Split layout */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
@media (max-width: 700px) { .split { grid-template-columns: 1fr; } }

/* Status */
.status {
  font-family: var(--font-mono);
  font-size: .8rem;
  padding: .35rem .7rem;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  gap: .35rem;
}
.status-ok { color: var(--success); }
.status-err { color: var(--error); }

/* Output pre */
.output-pre {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: .8rem;
  font-family: var(--font-mono);
  font-size: .85rem;
  white-space: pre-wrap;
  word-break: break-all;
  overflow-x: auto;
  min-height: 180px;
  line-height: 1.5;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: .6rem 1rem;
  font-size: .85rem;
  color: var(--text-primary);
  box-shadow: var(--shadow);
  opacity: 0;
  transform: translateY(10px);
  transition: all .2s ease;
  pointer-events: none;
  z-index: 999;
}
.toast.show { opacity: 1; transform: translateY(0); }

/* Highlight for regex */
mark { background: rgba(88,166,255,.3); color: var(--text-primary); border-radius: 2px; padding: 0 1px; }
mark.g1 { background: rgba(63,185,80,.3); }
mark.g2 { background: rgba(210,153,34,.3); }
mark.g3 { background: rgba(248,81,73,.3); }

/* Landing page */
.hero { text-align: center; padding: 3rem 0 2rem; }
.hero h1 { font-family: var(--font-mono); font-size: 2.2rem; margin-bottom: .5rem; }
.hero h1 span { color: var(--accent); }
.hero p { color: var(--text-secondary); font-size: 1.1rem; max-width: 600px; margin: 0 auto; }

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}
.tool-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-decoration: none;
  color: inherit;
  transition: all var(--transition);
  display: block;
}
.tool-card:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,.3); }
.tool-card h3 { font-family: var(--font-mono); font-size: 1rem; margin-bottom: .4rem; color: var(--accent); }
.tool-card p { color: var(--text-secondary); font-size: .9rem; }
.tool-icon { font-size: 1.5rem; margin-bottom: .5rem; }

.footer {
  text-align: center;
  padding: 2rem 0;
  color: var(--text-muted);
  font-size: .8rem;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

/* Tabs */
.tabs { display: flex; gap: 0; border-bottom: 1px solid var(--border); margin-bottom: 1rem; }
.tab {
  padding: .5rem 1rem;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: .85rem;
  font-family: var(--font-sans);
  transition: all var(--transition);
}
.tab:hover { color: var(--text-primary); }
.tab.active { color: var(--accent); border-bottom-color: var(--accent); }

/* Scrollbar */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--bg-tertiary); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--border); }