@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap');

:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4895ef;
    --text-color: #333;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --underweight-color: #4cc9f0;
    --normal-color: #4dd637;
    --overweight-color: #ffd166;
    --obese-color: #ef476f;
    --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    position: relative;
    overflow-x: hidden;
}

.particles-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.container {
    width: 100%;
    max-width: 800px;
    z-index: 1;
}

.card {
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: var(--card-shadow);
    overflow: hidden;
    transform: translateY(0);
    transition: transform 0.5s ease, box-shadow 0.5s ease;
    animation: fadeIn 1s ease-out;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.2);
}

.card-header {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 30px;
    text-align: center;
}

.card-header h1 {
    margin-bottom: 10px;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.card-header p {
    opacity: 0.8;
    font-weight: 300;
}

.card-body {
    padding: 30px;
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-color);
}

.input-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    transition: var(--transition);
}

.input-group input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

button {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 15px 25px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

button:hover {
    background: linear-gradient(to right, var(--secondary-color), var(--primary-color));
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(67, 97, 238, 0.3);
}

button:active {
    transform: translateY(0);
}

button::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 5px;
    height: 5px;
    background: rgba(255, 255, 255, 0.5);
    opacity: 0;
    border-radius: 100%;
    transform: scale(1, 1) translate(-50%);
    transform-origin: 50% 50%;
}

button:focus:not(:active)::after {
    animation: ripple 1s ease-out;
}

.result {
    margin-top: 30px;
    padding: 20px;
    border-radius: 10px;
    background-color: #f8f9fa;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    display: none;
    animation: slideDown 0.5s ease-out;
}

.result.show {
    display: block;
}

.result-value, .result-category {
    margin-bottom: 15px;
    font-size: 18px;
    font-weight: 500;
}

.result-value span, .result-category span {
    font-weight: 600;
    color: var(--primary-color);
}

.bmi-scale {
    display: flex;
    margin-top: 20px;
    position: relative;
    height: 40px;
    border-radius: 20px;
    overflow: hidden;
}

.scale-item {
    flex: 1;
    text-align: center;
    padding: 10px 0;
    font-size: 12px;
    font-weight: 600;
    color: white;
    position: relative;
}

.scale-item.underweight {
    background-color: var(--underweight-color);
}

.scale-item.normal {
    background-color: var(--normal-color);
}

.scale-item.overweight {
    background-color: var(--overweight-color);
}

.scale-item.obese {
    background-color: var(--obese-color);
}

.scale-pointer {
    position: absolute;
    bottom: 0;
    width: 10px;
    height: 40px;
    background-color: white;
    border: 2px solid #333;
    border-radius: 5px;
    transform: translateX(-50%);
    left: 0;
    transition: left 1s cubic-bezier(0.68, -0.55, 0.27, 1.55);
    z-index: 2;
}

.card-footer {
    padding: 20px 30px 30px;
    background-color: #f8f9fa;
}

.bmi-info h3 {
    margin-bottom: 15px;
    font-size: 18px;
    color: var(--dark-color);
}

.bmi-info ul {
    list-style: none;
}

.bmi-info li {
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.category-tag {
    display: inline-block;
    padding: 5px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    color: white;
}

.category-tag.underweight {
    background-color: var(--underweight-color);
}

.category-tag.normal {
    background-color: var(--normal-color);
}

.category-tag.overweight {
    background-color: var(--overweight-color);
}

.category-tag.obese {
    background-color: var(--obese-color);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes ripple {
    0% {
        transform: scale(0, 0);
        opacity: 1;
    }
    20% {
        transform: scale(25, 25);
        opacity: 1;
    }
    100% {
        opacity: 0;
        transform: scale(40, 40);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .card-header {
        padding: 20px;
    }
    
    .card-body, .card-footer {
        padding: 20px;
    }
    
    .scale-item {
        font-size: 10px;
    }
}

@media (max-width: 480px) {
    .card-header h1 {
        font-size: 24px;
    }
    
    .input-group input, button {
        padding: 12px;
    }
    
    .result-value, .result-category {
        font-size: 16px;
    }
    
    .scale-item {
        font-size: 8px;
        padding: 10px 0;
    }
    
    .bmi-info h3 {
        font-size: 16px;
    }
    
    .bmi-info li {
        font-size: 14px;
    }
}