:root {
  --bg: #0f172a;
  --card: #1e293b;
  --ink: #e2e8f0;
  --muted: #94a3b8;
  --line: #334155;
  --accent: #3b82f6;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
}

/* Header chung: xem header.css */

main {
  flex: 1;
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 16px;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

.tool-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 22px;
  color: var(--ink);
  text-decoration: none;
  transition: border-color 0.15s, transform 0.15s;
}
.tool-card:hover { border-color: var(--accent); transform: translateY(-2px); }
/* Layout card: hàng trên = icon + title, description nằm dưới. */
.tool-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
}
.tool-icon { font-size: 30px; }
.tool-card h2 { margin: 0; font-size: 17px; }
.tool-card p { margin: 0 0 14px; font-size: 14px; color: var(--muted); line-height: 1.5; }
.tool-go { font-size: 14px; color: var(--accent); font-weight: 600; }

.muted { color: var(--muted); font-size: 13px; }

.footer {
  padding: 16px;
  text-align: center;
  border-top: 1px solid var(--line);
}