body {
    margin: 0;
    font-family: Arial;
}

.gradient-bg {
    background: linear-gradient(45deg, #ff6b6b, #6a11cb, #2575fc);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.form-container {
    background: white;
    padding: 30px;
    border-radius: 10px;
    width: 300px;
    text-align: center;
}

input {
    width: 100%;
    padding: 8px;
    margin: 8px 0;
}

button {
    padding: 8px 12px;
    margin: 5px;
    background: #2575fc;
    color: white;
    border: none;
    cursor: pointer;
}

nav {
    background: #6a11cb;
    color: white;
    padding: 10px;
    display: flex;
    justify-content: space-between;
}

nav a {
    color: white;
    margin-left: 10px;
    text-decoration: none;
}

.hero {
    padding: 50px;
    text-align: center;
    background: linear-gradient(to right, #ff9a9e, #fad0c4);
}

.image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 10px;
    padding: 20px;
}

.image-gallery img {
    width: 100%;
    border-radius: 10px;
}

.instructions {
    padding: 40px;
}

ul {
    list-style: none;
}
.dark-mode {
    background: #121212;
    color: white;
}

.dark-mode nav {
    background: black;
}

.dark-mode .bmi-box,
.dark-mode .form-container {
    background: #1e1e1e;
    color: white;
}
.progress-bar {
    width: 100%;
    background: #ddd;
    border-radius: 20px;
    overflow: hidden;
    height: 20px;
    margin-top: 10px;
}

#progressFill {
    height: 100%;
    width: 0%;
    background: linear-gradient(45deg, #00f260, #0575e6);
    transition: 0.5s;
}
body {
    animation: gradientBG 10s ease infinite;
    background: linear-gradient(-45deg, #ff9a9e, #fad0c4, #a18cd1, #fbc2eb);
    background-size: 400% 400%;
}

@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}