:root {
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --text-color: #333333;
    --header-bg: #2e7d32; /* Healthy Green */
    --header-text: #ffffff;
    --primary-color: #4caf50;
    --primary-hover: #45a049;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

body.dark-mode {
    --bg-color: #121212;
    --card-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --header-bg: #1b5e20;
    --header-text: #ffffff;
    --primary-color: #81c784;
    --primary-hover: #a5d6a7;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.5);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: var(--transition);
}

header {
    background-color: var(--header-bg);
    color: var(--header-text);
    padding: 1.5rem;
    text-align: center;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
}

h1 {
    margin: 0;
    font-size: 1.5rem;
    flex-grow: 1;
}

#theme-toggle {
    background: none;
    border: 2px solid var(--header-text);
    color: var(--header-text);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 5px 10px;
    border-radius: 50%;
    transition: var(--transition);
}

#theme-toggle:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: scale(1.1);
}

main {
    padding: 2rem 1rem;
    max-width: 700px;
    margin: 0 auto;
}

form, #recommendation {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

h2 {
    margin-top: 0;
    color: var(--primary-color);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

@media (max-width: 600px) {
    .form-row {
        grid-template-columns: 1fr;
    }
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

select, input[type="number"] {
    width: 100%;
    padding: 0.75rem;
    border-radius: 8px;
    border: 1px solid #ccc;
    background-color: var(--card-bg);
    color: var(--text-color);
    font-size: 1rem;
    box-sizing: border-box;
}

input[type="number"]:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 2px rgba(76, 175, 80, 0.2);
}

button[type="submit"] {
    display: block;
    width: 100%;
    padding: 1rem;
    border: none;
    background-color: var(--primary-color);
    color: #fff;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: bold;
    transition: var(--transition);
}

button[type="submit"]:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.metrics {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: space-between;
    font-size: 0.95rem;
}

.metrics p {
    margin: 0.2rem 0;
}

#diet-plan {
    border-left: 4px solid var(--primary-color);
    padding-left: 1rem;
    margin-top: 1rem;
}

ul {
    padding-left: 1.2rem;
}

li {
    margin-bottom: 0.5rem;
}