/* Reset and Global */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f2f5f7;
    color: #333;
    line-height: 1.6;
}

/* Header */
header {
    background: linear-gradient(90deg, #007bff, #00c6ff);
    color: white;
    text-align: center;
    padding: 40px 20px;
}

header h1 {
    font-size: 2.2em;
    margin-bottom: 10px;
}

header p {
    font-size: 1.1em;
}

/* Navigation */
nav {
    background: #fff;
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    flex-wrap: wrap;
}

nav ul li {
    margin: 10px 20px;
}

nav ul li a {
    text-decoration: none;
    color: #007bff;
    font-weight: bold;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: #0056b3;
}

/* Main & Calculators */
main {
    max-width: 900px;
    margin: 30px auto;
    padding: 0 15px;
}

.calculator {
    background: #fff;
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 30px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.calculator:hover {
    transform: translateY(-5px);
}

.calculator h2 {
    margin-bottom: 20px;
    color: #007bff;
}

.calculator label {
    display: block;
    margin-bottom: 12px;
    font-weight: 600;
}

.calculator input {
    width: 100%;
    padding: 10px;
    margin-top: 5px;
    border-radius: 8px;
    border: 1px solid #ccc;
    transition: border 0.3s;
}

.calculator input:focus {
    border: 2px solid #007bff;
    outline: none;
}

.calculator button {
    background: #007bff;
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1em;
    margin-top: 10px;
    transition: background 0.3s;
}

.calculator button:hover {
    background: #0056b3;
}

.result {
    font-weight: bold;
    margin-top: 15px;
    color: #333;
    font-size: 1.1em;
}

/* Footer */
footer {
    background: #007bff;
    color: white;
    text-align: center;
    padding: 25px 10px;
    margin-top: 40px;
    font-size: 0.9em;
}

footer a {
    color: #ffd700;
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 650px) {
    nav ul {
        flex-direction: column;
        align-items: center;
    }
    nav ul li {
        margin: 8px 0;
    }
}