:root {
  --bg: #0f172a; --card: #1e293b; --border: #334155;
  --text: #e2e8f0; --muted: #94a3b8; --accent: #3b82f6;
  --accent2: #10b981; --danger: #ef4444;
}
* { margin:0; padding:0; box-sizing:border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; background: var(--bg); color: var(--text); min-height: 100vh; line-height: 1.6; }
a { color: var(--accent); text-decoration: none; }

/* Top navigation */
.topnav {
  background: var(--card); border-bottom: 1px solid var(--border);
  padding: 0 20px; display: flex; align-items: center; gap: 16px;
  height: 52px; position: sticky; top: 0; z-index: 100;
}
.topnav a { color: #fff; font-weight: 600; font-size: 16px; }
.topnav .nav-sub { color: var(--muted); font-size: 12px; }
.topnav .nav-right { margin-left: auto; display: flex; gap: 8px; align-items: center; }
.topnav .nav-right a { font-size: 13px; color: var(--muted); font-weight: 400; }
.topnav .nav-right a:hover { color: #fff; }

/* Container */
.container { max-width: 960px; margin: 0 auto; padding: 24px 20px; }

/* Hero section on home */
.hero { text-align: center; padding: 40px 0 24px; }
.hero h1 { font-size: 32px; color: #fff; margin-bottom: 8px; }
.hero p { color: var(--muted); font-size: 15px; max-width: 600px; margin: 0 auto; }

/* Tool grid on home */
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 12px; margin: 20px 0; }
.tool-card {
  display: block; background: var(--card); border: 1px solid var(--border);
  border-radius: 10px; padding: 16px; transition: all 0.2s; color: var(--text);
}
.tool-card:hover { border-color: var(--accent); background: rgba(59,130,246,0.08); }
.tool-card .card-icon { font-size: 24px; margin-bottom: 8px; }
.tool-card h3 { font-size: 15px; color: #fff; margin-bottom: 4px; }
.tool-card p { font-size: 12px; color: var(--muted); }
.cat-label { font-size: 13px; color: var(--muted); margin: 24px 0 8px; padding-bottom: 4px; border-bottom: 1px solid var(--border); }

/* Tool page */
.tool-page h2 { font-size: 24px; color: #fff; margin-bottom: 4px; }
.tool-page .subtitle { color: var(--muted); font-size: 13px; margin-bottom: 20px; }
.breadcrumb { font-size: 12px; color: var(--muted); margin-bottom: 12px; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: #fff; }

/* Cards */
.card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 20px; margin-bottom: 16px; }
.card h3 { font-size: 15px; color: #fff; margin-bottom: 12px; }

/* Form elements */
label { display: block; font-size: 12px; color: var(--muted); margin-bottom: 4px; }
input, select, textarea {
  width: 100%; padding: 10px 14px; background: var(--bg);
  border: 1px solid var(--border); border-radius: 8px;
  color: #fff; font-size: 14px; outline: none; font-family: inherit;
}
input:focus, select:focus, textarea:focus { border-color: var(--accent); }
textarea { resize: vertical; min-height: 120px; font-family: 'Consolas', 'Monaco', monospace; font-size: 13px; }
.form-row { display: flex; gap: 10px; align-items: flex-end; margin-bottom: 12px; flex-wrap: wrap; }
.form-row .field { flex: 1; min-width: 120px; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 10px 20px; border-radius: 8px; font-size: 14px; font-weight: 500;
  cursor: pointer; border: none; transition: all 0.15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #2563eb; }
.btn-outline { background: transparent; border: 1px solid var(--border); color: #fff; }
.btn-outline:hover { border-color: var(--accent); }
.btn-sm { padding: 5px 12px; font-size: 12px; }

/* Result */
.result {
  margin-top: 12px; padding: 14px; background: rgba(16,185,129,0.08);
  border: 1px solid rgba(16,185,129,0.2); border-radius: 8px;
  font-family: 'Consolas', 'Monaco', monospace; font-size: 13px;
  white-space: pre-wrap; word-break: break-all; max-height: 400px; overflow-y: auto;
}
.result.error { background: rgba(239,68,68,0.08); border-color: rgba(239,68,68,0.2); color: #fca5a5; }
.val { font-size: 22px; font-weight: bold; color: var(--accent2); }
.unit { font-size: 12px; color: var(--muted); }

/* Tables */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 13px; }
th { padding: 10px 12px; text-align: left; color: #fff; background: rgba(59,130,246,0.12); font-weight: 600; }
td { padding: 8px 12px; border-top: 1px solid var(--border); }
tr:hover td { background: rgba(255,255,255,0.02); }

/* Ad units */
.ad-placeholder {
  background: var(--card); border: 1px dashed var(--border);
  border-radius: 8px; min-height: 90px; margin: 16px 0;
  display: flex; align-items: center; justify-content: center;
  color: var(--muted); font-size: 11px;
}

/* Toast */
.toast {
  position: fixed; bottom: 30px; left: 50%; transform: translateX(-50%);
  background: var(--accent2); color: #000; padding: 10px 24px;
  border-radius: 20px; font-size: 13px; font-weight: 600; z-index: 999;
  animation: toastIn 0.3s, toastOut 0.3s 1.7s forwards;
}
@keyframes toastIn { from { opacity:0; transform: translateX(-50%) translateY(10px); } }
@keyframes toastOut { to { opacity:0; transform: translateX(-50%) translateY(-10px); } }

/* Donation section */
.donate-section {
  text-align: center; padding: 32px 20px; margin: 32px 0 0;
  border-top: 1px solid var(--border);
}
.donate-section .donate-title { font-size: 16px; color: #fff; margin-bottom: 6px; }
.donate-section .donate-sub { font-size: 12px; color: var(--muted); margin-bottom: 20px; }
.donate-section .donate-codes { display: flex; justify-content: center; gap: 24px; flex-wrap: wrap; }
.donate-section .donate-code { text-align: center; }
.donate-section .donate-code img {
  width: 160px; height: 160px; border-radius: 8px; border: 1px solid var(--border);
  margin-bottom: 6px; display: block;
}
.donate-section .donate-code span { font-size: 11px; color: var(--muted); }

/* Footer */
footer { text-align: center; padding: 20px; color: var(--muted); font-size: 11px; border-top: 1px solid var(--border); }

@media (max-width: 768px) {
  .tool-grid { grid-template-columns: repeat(2, 1fr); }
  .topnav { padding: 0 12px; }
  .hero h1 { font-size: 24px; }
}