* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; color: #1a1a1a; background: #f5f5f5; line-height: 1.5; }
nav { background: #2c3e50; padding: 0.5rem 1.5rem; display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap; }
nav a { color: #ecf0f1; text-decoration: none; font-size: 0.9rem; padding: 0.3rem 0.6rem; border-radius: 4px; transition: background 0.2s; }
nav a:hover { background: rgba(255,255,255,0.15); }
nav a.active { background: rgba(255,255,255,0.2); font-weight: 600; }
nav .brand { font-weight: 700; font-size: 1rem; margin-right: auto; }
.container { max-width: 800px; margin: 2rem auto; padding: 0 1.5rem; }
h1 { font-size: 1.5rem; margin-bottom: 0.5rem; color: #2c3e50; }
p { margin-bottom: 0.75rem; }
.result { background: #fff; border: 1px solid #ddd; border-radius: 6px; padding: 1rem; margin-bottom: 1.5rem; }
.result-label { font-weight: 600; margin-bottom: 0.5rem; color: #27ae60; }
textarea { width: 100%; font-family: monospace; font-size: 0.9rem; padding: 0.75rem; border: 1px solid #ccc; border-radius: 6px; resize: vertical; }
textarea:disabled { background: #f9f9f9; color: #333; }
label { font-size: 0.9rem; }
input[type="text"], input[type="number"], select { padding: 0.5rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; }
input[type="submit"] { background: #2c3e50; color: #fff; border: none; padding: 0.6rem 1.5rem; border-radius: 4px; font-size: 0.9rem; cursor: pointer; transition: background 0.2s; }
input[type="submit"]:hover { background: #34495e; }
.radio-group, .options-group { margin: 1rem 0; display: flex; gap: 1.5rem; align-items: center; flex-wrap: wrap; }
.form-row { margin-bottom: 1rem; }
.form-row label { display: block; font-weight: 600; margin-bottom: 0.3rem; }
.form-row input[type="text"], .form-row select, .form-row textarea { width: 100%; }
.tool-card { background: #fff; border: 1px solid #ddd; border-radius: 8px; padding: 1.5rem; margin-bottom: 1rem; transition: box-shadow 0.2s; }
.tool-card:hover { box-shadow: 0 2px 8px rgba(0,0,0,0.1); }
.tool-card h2 { font-size: 1.1rem; margin-bottom: 0.3rem; }
.tool-card h2 a { color: #2c3e50; text-decoration: none; }
.tool-card h2 a:hover { color: #3498db; }
.tool-card p { color: #666; font-size: 0.9rem; margin: 0; }