body { font-family: Arial, sans-serif; margin: 0; padding: 0; }
header { background: #0077cc; color: #fff; padding: 1em; }
.navbar { display: flex; justify-content: space-between; align-items: center; }
.nav-links a { margin-left: 1em; color: #fff; text-decoration: none; }
footer { background: #333; color: #fff; text-align: center; padding: 1em; margin-top: 2em; }
.ad-top, .ad-right, .ad-bottom { margin: 1em 0; padding: 1em; text-align: center; background: #eee; border: 1px dashed #aaa; }
.content-section { margin: 1em; }
.calculator-card { margin: 1em 0; padding: 1em; border: 1px solid #ccc; border-radius: 8px; background: #f9f9f9; }
.form-group { margin: 0.5em 0; }
.form-group label { display: block; margin-bottom: 0.3em; }
.form-group input { width: 100%; padding: 0.4em; }
button { margin-top: 0.5em; padding: 0.5em 1em; cursor: pointer; background: #0077cc; color: #fff; border: none; border-radius: 4px; }
.result { margin-top: 1em; padding: 0.5em; background: #eef; border-left: 3px solid #0077cc; }