:root {
    --primary: #2A5470;  
    --secondary: #4CAF50; 
    --background: #f8f9fa;
}
body {
    font-family: 'Segoe UI', Tahoma, sans-serif;
    background: var(--background);
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    line-height: 1.6;
}
.container {
    max-width: 800px;
    margin: 20px auto;
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
}
h1 {
    color: var(--primary);
    text-align: center;
    margin-bottom: 15px;
    font-size: 2.8em;
}
h2 {
    color: var(--primary);
    margin-top: 30px;
    border-bottom: 2px solid var(--primary);
    padding-bottom: 8px;
}
.subtitle {
    text-align: center;
    color: #666;
    font-size: 1.1em;
    margin-bottom: 40px;
    color:#ddd;
}
section {
    margin: 30px 0;
    padding: 20px;
    background: linear-gradient(145deg, #f8f9fa, #fff);
    border-radius: 10px;
}
ol, ul {
    padding-left: 25px;
    margin: 15px 0;
}
li {
    margin: 10px 0;
    padding-left: 10px;
}
strong {
    color: var(--primary);
}
.input-group {
    text-align: center;
    margin: 40px 0;
}
input {
    padding: 15px;
    width: 70%;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
    margin: 10px 0;
    transition: border-color 0.3s;
}
input:focus {
    border-color: var(--primary);
    outline: none;
}
button {
    background: var(--primary);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: transform 0.2s, background 0.3s;
}
button:hover {
    background: #1d3a4d;
    transform: translateY(-2px);
}
.faq-section {
    background: #fff3e6;
    padding: 20px;
    border-radius: 10px;
    margin: 25px 0;
}
#result {
    margin-top: 30px;
    padding: 25px;
    background: linear-gradient(145deg, #f8f9fa, #fff);
    border-radius: 10px;
    border: 1px solid #eee;
}
.number-circle {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--secondary);
    color: white;
    font-size: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 20px auto;
}
.calculation-steps {
    text-align: center;
    color: #666;
    margin: 15px 0;
}
.details-section {
    margin-top: 25px;
    padding: 15px;
    background: #fff9e6;
    border-radius: 8px;
}
.details-section h3 {
    color: var(--primary);
    margin-top: 0;
}
.example-text {
    color: #666;
    font-style: italic;
    margin: 10px 0;
}
/* Navigation Bar Styles */
nav {
    background: var(--primary);
    padding: 15px 0;
    text-align: center;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
    gap: 20px;
}

nav ul li {
    display: inline;
}

nav ul li a {
    color: white;
    text-decoration: none;
    font-size: 18px;
    padding: 12px 18px;
    transition: background 0.3s, border-radius 0.3s, transform 0.2s;
}

nav ul li a:hover {
    background: var(--secondary);
    border-radius: 5px;
    transform: translateY(-2px);
}