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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: #f0f2f5;
    color: #222;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.1);
    padding: 40px 36px;
    width: 100%;
    max-width: 420px;
}

h1 {
    font-size: 1.8rem;
    margin-bottom: 4px;
}

.subtitle {
    color: #666;
    margin-bottom: 28px;
    font-size: 0.95rem;
}

.field {
    margin-bottom: 18px;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 6px;
    font-size: 0.9rem;
}

input[type="number"] {
    width: 100%;
    padding: 10px 14px;
    border: 1.5px solid #d0d5dd;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

input[type="number"]:focus {
    outline: none;
    border-color: #4a7cf0;
}

button {
    width: 100%;
    padding: 12px;
    background: #4a7cf0;
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 6px;
    transition: background 0.2s;
}

button:hover {
    background: #3563d4;
}

.result {
    margin-top: 28px;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
}

.bmi-value {
    font-size: 2.8rem;
    font-weight: 700;
    line-height: 1;
}

.bmi-category {
    font-size: 1.1rem;
    font-weight: 600;
    margin-top: 6px;
}

.normal    { background: #d4edda; color: #1a5c2a; }
.overweight { background: #fff3cd; color: #7a5300; }
.obese     { background: #f8d7da; color: #7a1a20; }
.underweight { background: #cce5ff; color: #00407a; }
.error     { background: #f8d7da; color: #7a1a20; font-weight: 500; }

.scale {
    margin-top: 28px;
    border-top: 1px solid #eee;
    padding-top: 20px;
}

.scale h2 {
    font-size: 0.95rem;
    color: #666;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.scale ul {
    list-style: none;
}

.scale li {
    padding: 6px 12px;
    border-radius: 6px;
    margin-bottom: 4px;
    font-size: 0.88rem;
    font-weight: 500;
}