body { font-family: "Segoe UI", sans-serif; background-color: #f0f2f5; display: flex; justify-content: center; align-items: center; height: 100vh; margin: 0; }
.calculator-container { background: #ffffff; padding: 30px; border-radius: 10px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); width: 100%; max-width: 400px; position: relative; }
.lang-switch { position: absolute; top: 15px; right: 15px; }
.lang-switch button { background: #e0e0e0; border: none; padding: 5px 10px; border-radius: 5px; cursor: pointer; font-size: 12px; margin-left: 5px; }
.lang-switch button.active { background: #0056b3; color: white; }
h1 { font-size: 22px; text-align: center; color: #1a1a1a; margin-bottom: 20px; margin-top: 10px; }
.input-group { margin-bottom: 15px; }
label { display: block; margin-bottom: 5px; color: #555; font-size: 14px; }
input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 6px; font-size: 16px; box-sizing: border-box; }
button#btn-calc { width: 100%; padding: 12px; background-color: #0056b3; color: white; border: none; border-radius: 6px; font-size: 16px; cursor: pointer; transition: background 0.3s; }
button#btn-calc:hover { background-color: #004494; }
.results { margin-top: 20px; padding-top: 20px; border-top: 1px solid #eee; }
.result-item { display: flex; justify-content: space-between; margin-bottom: 10px; font-size: 15px; color: #333; }
.result-item strong { color: #28a745; font-size: 16px; }
.hidden { display: none; }