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

:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --primary: #4f6ef7;
  --primary-dark: #3a56d4;
  --primary-light: #eef1fe;
  --text: #1a1d2e;
  --muted: #6b7280;
  --border: #e5e7eb;
  --radius: 14px;
  --shadow: 0 2px 12px rgba(0,0,0,0.07);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.10);
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ── Header ── */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}
.logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
.logo-icon { font-size: 1.4rem; }
nav { display: flex; gap: 20px; align-items: center; }
nav a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s;
}
nav a:hover { color: var(--primary); }

/* ── Footer ── */
footer {
  text-align: center;
  padding: 32px 16px;
  font-size: 0.8rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
  background: var(--surface);
  margin-top: 64px;
}
footer a { color: var(--primary); text-decoration: none; }