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

:root {
    --olive-green: #708238;
    --light-olive: #9db56b;
    --dark-olive: #3d4b26;
    --background: #f4f6f0;
}

body {
    font-family: 'Prompt', sans-serif;
    background-color: var(--background);
    color: var(--dark-olive);
    line-height: 1.6;
}

h2 {
    text-align: center; /* จัดกึ่งกลางข้อความ */
    margin: 10px 0; /* เพิ่มระยะห่างด้านบนและล่าง */
}

/* Header Styles - Enhanced */
.main-header {
    background-color: var(--dark-olive);
    color: white;
    padding: 1.5rem 0;
    box-shadow: 
        0 4px 6px rgba(0,0,0,0.1), 
        0 1px 3px rgba(0,0,0,0.08);
    position: relative;
    overflow: hidden;
}

.header-container {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 5%;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    z-index: 2;
}

.brand-name {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 1.5px;
    text-align: center;
    
    /* Text Shadow for Depth */
    text-shadow: 
        2px 2px 4px rgba(0,0,0,0.3),
        -1px -1px 2px rgba(255,255,255,0.1);
    
    /* Cross-browser Gradient Text */
    background: linear-gradient(
        to right, 
        var(--light-olive), 
        #ffffff
    );
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    -webkit-text-fill-color: transparent;
    
    /* Subtle Hover Effect */
    transition: transform 0.3s ease;
}

.brand-name:hover {
    transform: scale(1.05);
}

/* Optional Background Animation */
.main-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        45deg, 
        rgba(61, 75, 38, 0.9), 
        rgba(112, 130, 56, 0.7)
    );
    opacity: 0.7;
    z-index: 1;
    animation: headerWave 10s ease infinite;
}

@keyframes headerWave {
    0% {
        transform: skewX(-5deg) translateX(-50%);
    }
    50% {
        transform: skewX(5deg) translateX(50%);
    }
    100% {
        transform: skewX(-5deg) translateX(-50%);
    }
}

/* Container Styles */
.container {
    max-width: 500px;
    margin: 2rem auto;
    padding: 0 15px;
}

.container h1 {
    text-align: center;
    color: var(--dark-olive);
    margin-bottom: 1.5rem;
    font-weight: 600;
}

/* Calculator Card */
.calculator-card {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(61, 75, 38, 0.1);
    padding: 2rem;
    border-left: 6px solid var(--olive-green);
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--dark-olive);
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--light-olive);
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--olive-green);
    box-shadow: 0 0 0 3px rgba(112, 130, 56, 0.2);
}

.calculate-btn {
    width: 100%;
    padding: 1rem;
    background-color: var(--olive-green);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
}

.calculate-btn:hover {
    background-color: var(--dark-olive);
    transform: translateY(-2px);
}

.result {
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: white;
    border-radius: 6px;
    color: var(--dark-olive);
}

/* Footer Styles */
.main-footer {
    background-color: var(--dark-olive);
    color: var(--light-olive);
    padding: 2rem 0;
    margin-top: 2rem;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.contact-info h3 {
    margin-bottom: 0.5rem;
    color: white;
}

.contact-info p {
    color: var(--light-olive);
    font-size: 0.9rem;
}

.copyright {
    font-size: 0.9rem;
    color: var(--light-olive);
}

/* Responsive Design */
@media (max-width: 600px) {
    .footer-container {
        flex-direction: column;
        text-align: center;
    }

    .contact-info {
        margin-bottom: 1rem;
    }
}