:root {
  --bg: #f3f5f9;
  --panel: #ffffff;
  --panel-soft: #fbfdff;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --btn-secondary: #334155;
  --topbar-bg: #eaf1fb;
  --topbar-text: #0f172a;
  --border: #dbe2ea;
  --input-bg: #ffffff;
  --input-text: #1f2937;
}

:root[data-theme="dark"] {
  --bg: #0b1220;
  --panel: #121a2a;
  --panel-soft: #172033;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --accent: #3b82f6;
  --btn-secondary: #1f2937;
  --topbar-bg: #020617;
  --topbar-text: #e5e7eb;
  --border: #263247;
  --input-bg: #111827;
  --input-text: #e5e7eb;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}
a { color: inherit; }

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  background: var(--topbar-bg);
  color: var(--topbar-text);
}
.topbar h1 { margin: 0; font-size: 1.45rem; }
.topbar-nav { display: flex; align-items: center; gap: 0.75rem; }
.topbar-link {
  padding: 0.35rem 0.5rem;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--topbar-text);
  font: inherit;
  font-size: 0.92rem;
  text-decoration: underline;
  text-underline-offset: 0.15em;
  cursor: pointer;
}
.topbar-link:hover,.topbar-link:focus-visible {
  background: color-mix(in srgb, var(--topbar-text) 12%, transparent);
  outline: none;
}
.theme-toggle-btn {
  width: 38px;
  height: 38px;
  padding: 0;
  min-width: 38px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: color-mix(in srgb, var(--topbar-text) 10%, transparent);
  color: var(--topbar-text);
  cursor: pointer;
}
.theme-toggle-btn svg { width: 22px; height: 22px; display: block; margin: auto; }

.container { max-width: 1200px; margin: 1rem auto; padding: 0 1rem 2rem; }
.panel { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 1.2rem; }
.muted { color: var(--muted); }

.hero { margin-bottom: 1rem; }
.hero h2 { margin: 0 0 0.4rem; font-size: 1.6rem; }
.hero p { margin: 0.2rem 0 0.8rem; line-height: 1.5; }
.disclaimer {
  margin-top: 0.8rem;
  padding: 0.75rem 0.9rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--panel-soft);
  font-size: 0.9rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0.9rem;
  margin-top: 1rem;
}
.tool-card {
  display: block;
  text-decoration: none;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
  background: var(--panel-soft);
  transition: transform .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.tool-card:hover,.tool-card:focus-visible {
  transform: translateY(-1px);
  border-color: var(--accent);
  box-shadow: 0 6px 20px rgba(15, 23, 42, .12);
  outline: none;
}
.tool-card h3 { margin: 0 0 0.3rem; font-size: 1.08rem; }
.tool-card p { margin: 0; color: var(--muted); }
.tool-icon { font-size: 1.25rem; margin-bottom: 0.35rem; display: inline-block; }
.page-intro { margin-bottom: 0.9rem; }