/* base.css — reset, CSS variables, typography, ortak buton */
:root {
  --sky: #007AFF;
  --sky-dark: #0056b3;
  --sky-pale: #cfe4ff;
  --ink: #1a1a1a;
  --ink-soft: #666;
  --bg: #f5f9ff;
  --white: #fff;
  --radius: 10px;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.10);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.5;
}
a { color: var(--sky); text-decoration: none; }
a:hover { text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
h1, h2, h3, h4 { margin: 0 0 12px; line-height: 1.25; }

.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-weight: 600;
  cursor: pointer;
  border: none;
  font-family: inherit;
  font-size: 15px;
  transition: transform 0.15s ease, opacity 0.15s ease;
}
.btn--primary { background: var(--sky); color: var(--white); }
.btn--primary:hover { opacity: 0.9; }
.btn--ghost { background: transparent; color: var(--sky); border: 1.5px solid var(--sky); }
.btn--ghost:hover { background: var(--sky); color: var(--white); }
.btn--lg { padding: 16px 32px; font-size: 17px; }