/* Reset default styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Body */
body {
    background-color: #f7f9fc;
    color: #333;
    line-height: 1.6;
}

/* Container for padding */
.container {
    width: 90%;
    max-width: 900px;
    margin: auto;
    padding: 20px 0;
}

/* Header */
header {
    background-color: #1e90ff;
    color: #fff;
    text-align: center;
    padding: 40px 0;
}

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

header p {
    font-size: 1.1rem;
}

/* Navigation bar */
nav {
    background-color: #fff;
    border-bottom: 2px solid #1e90ff;
}

nav .container {
    display: flex;
    justify-content: center;
    gap: 30px;
    padding: 12px 0;
}

nav a {
    text-decoration: none;
    color: #1e90ff;
    font-weight: bold;
    transition: color 0.3s ease;
}

nav a:hover {
    color: #0d3c91;
}

/* Main content */
main h2 {
    text-align: center;
    margin-bottom: 25px;
    font-size: 1.8rem;
}

/* Calculator container */
.calculator-container {
    background-color: #fff;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

/* Input fields */
.calculator-inputs input {
    width: 45%;
    padding: 12px;
    margin: 8px 2%;
    border-radius: 6px;
    border: 1px solid #ccc;
    font-size: 1rem;
}

/* Buttons */
.calculator-buttons {
    text-align: center;
    margin-top: 20px;
}

.calculator-buttons button {
    padding: 12px 20px;
    margin: 6px;
    border: none;
    border-radius: 8px;
    background-color: #1e90ff;
    color: #fff;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.calculator-buttons button:hover {
    background-color: #0d3c91;
}

/* Result display */
.calculator-result {
    text-align: center;
    margin-top: 20px;
    font-weight: bold;
    font-size: 1.2rem;
    color: #1e90ff;
}

/* History list */
.calculator-history {
    list-style-type: none;
    margin-top: 15px;
    padding-left: 0;
    max-height: 150px;
    overflow-y: auto;
}

.calculator-history li {
    background-color: #f1f5f9;
    margin: 5px 0;
    padding: 8px 12px;