/* Modern BMI Calculator Styles */
:root {
    --primary-color: #6a5acd; /* Soft indigo */
    --secondary-color: #7b68ee; /* Medium slate blue */
    --background-color: #f4f6f9; /* Soft light gray */
    --text-color-dark: #2c3e50; /* Deep navy blue */
    --text-color-light: #4a5568; /* Muted gray-blue */
    --accent-color: #5e81ac; /* Soft blue */
}

html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
}

body {
    font-family: "Inter", "Segoe UI", Roboto, system-ui, -apple-system, sans-serif;
    background: linear-gradient(
            135deg,
            var(--primary-color),
            var(--secondary-color),
            var(--accent-color)
    );
    background-size: 400% 400%;
    animation: gradientFlow 12s ease infinite;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100%;
    color: var(--text-color-dark);
    line-height: 1.6;
}

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

.container {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(15px) saturate(180%);
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1), 0 10px 20px rgba(0, 0, 0, 0.05);
    padding: 3rem;
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    border: 1px solid rgba(255, 255, 255, 0.4);
    transition: all 0.3s ease;
    margin: auto;
}

.container:hover {
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.12), 0 15px 25px rgba(0, 0, 0, 0.08);
}

h1 {
    font-size: 2.75rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 2rem;
    text-align: center;
    letter-spacing: -1px;
}

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

label {
    display: block;
    margin-bottom: 0.75rem;
    font-weight: 600;
    color: var(--text-color-light);
    font-size: 1rem;
    transition: color 0.3s ease;
}

.large-input {
    width: 90%;
    padding: 1rem 1.25rem;
    border: 2px solid rgba(94, 129, 172, 0.3);
    border-radius: 16px;
    font-size: 1.1rem;
    background: rgba(255, 255, 255, 0.7);
    transition: border-color 0.3s ease, box-shadow 0.3s ease, transform 0.2s ease;
}

.large-input:focus {
    border-color: var(--accent-color);
    outline: none;
    box-shadow: 0 0 0 4px rgba(94, 129, 172, 0.2);
    transform: scale(1.01);
}

button {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 1.1rem 2.2rem;
    border-radius: 16px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
    width: 100%;
    letter-spacing: 0.5px;
}

button:hover {
    background: var(--secondary-color);
    transform: translateY(-1px);
    box-shadow: 0 8px 20px rgba(106, 90, 205, 0.3);
}

button:active {
    transform: translateY(0);
    box-shadow: 0 4px 10px rgba(106, 90, 205, 0.2);
}

#bmiResults {
    background: rgba(236, 240, 241, 0.7);
    border-radius: 16px;
    padding: 1.5rem;
    margin-top: 2rem;
    font-size: 1.3rem;
    color: var(--text-color-dark);
    text-align: center;
    font-weight: 500;
    opacity: 0;
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in {
    opacity: 1;
    transform: translateY(0);
    animation: softFadeIn 0.6s cubic-bezier(0.25, 0.1, 0.25, 1) forwards;
}

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

/* Enhanced Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 1rem;
        align-items: center;
    }

    .container {
        width: calc(100% - 2rem);
        max-width: 100%;
        padding: 2rem;
        margin: auto;
    }
}

@media (max-height: 600px) {
    .container {
        max-height: 95vh;
        padding: 2rem;
    }

    h1 {
        font-size: 2rem;
        margin-bottom: 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        width: 100%;
        padding: 1.5rem;
        border-radius: 20px;
        margin: auto;
    }

    h1 {
        font-size: 1.8rem;
    }

    .large-input,
    button {
        font-size: 1rem;
        padding: 0.9rem 1.2rem;
    }
}