:root {
    --primary-gradient-start: #8e2de2;
    --primary-gradient-end: #4a00e0;
    --secondary-gradient-start: #fc5c7d;
    --secondary-gradient-end: #6a82fb;
    --card-background-rgb: 255, 255, 255;
    --text-color: #333;
    --sub-text-color: #666;
    --error-color: #e74c3
    --success-color: #2ecc71;
    --border-radius: 15px;
}
body {
    font-family: 'Inter', sans-serif;
    color: var(--text-color);
    display: flex;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    padding-bottom: 80px; 
    position: relative;
    overflow-x: hidden;
}
.background-animation {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        45deg,
        var(--primary-gradient-start),
        var(--secondary-gradient-start),
        var(--primary-gradient-end),
        var(--secondary-gradient-end)
    );
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
    z-index: -1;
}
@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}
.container {
    background-color: rgba(var(--card-background-rgb), 0.8);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(var(--card-background-rgb), 0.3);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.25);
    max-width: 480px;
    width: 100%;
    transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
    position: relative;
    z-index: 1;
}
.container:hover {
    transform: translateY(-5px);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.35);
}
h1 {
    font-family: 'Pacifico', cursive;
    font-size: 36px;
    background: linear-gradient(90deg, var(--primary-gradient-start), var(--secondary-gradient-start));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-align: center;
    margin-bottom: 35px;
    padding-bottom: 15px;
    border-bottom: 3px dashed rgba(var(--card-background-rgb), 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}
h1 i {
    font-size: 30px;
    color: var(--primary-gradient-end);
    animation: iconBounce 1s ease-in-out infinite alternate;
}
@keyframes iconBounce {
    from { transform: translateY(0); }
    to { transform: translateY(-5px); }
}

.form-group {
    margin-bottom: 25px;
}
.form-group label {
    display: block;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 10px;
    font-size: 16px;
}
.form-group input,
.form-group select {
    width: 100%;
    padding: 15px;
    font-size: 17px;
    border: 1px solid rgba(0, 0, 0, 0.2);
    border-radius: 10px;
    box-sizing: border-box;
    background-color: rgba(var(--card-background-rgb), 0.7);
    transition: all 0.3s ease;
    color: var(--text-color);
}
.form-group input::placeholder {
    color: var(--sub-text-color);
    opacity: 0.8;
    font-style: italic;
}
.form-group input:focus {
    border-color: var(--primary-gradient-end);
    outline: none;
    box-shadow: 
        0 0 15px rgba(74, 0, 224, 0.5), 
        inset 0 1px 5px rgba(0, 0, 0, 0.1); 
    background-color: rgba(var(--card-background-rgb), 0.9);
}
.select2-container--default .select2-selection--single {
    height: 47px;
    border-radius: 10px;
    border: 1px solid rgba(0, 0, 0, 0.2);
    background-color: rgba(var(--card-background-rgb), 0.7);
    transition: all 0.3s ease;
}
.select2-container--default .select2-selection--single .select2-selection__rendered {
    color: var(--text-color);
    line-height: 45px;
    padding-left: 15px;
    font-size: 17px;
}
.select2-container--default .select2-selection--single .select2-selection__arrow {
    height: 45px;
    width: 30px;
}
.select2-container--default .select2-selection--single .select2-selection__arrow b {
    border-color: var(--primary-gradient-end) transparent transparent transparent !important;
    border-width: 6px 4px 0 4px !important;
    margin-top: -3px !important;
}
.select2-container--default .select2-results__option--highlighted.select2-results__option--selectable {
    background-color: var(--primary-gradient-end) !important;
    color: white;
}
.select2-container--default .select2-results__option--selected {
    background-color: #eee;
}
.select2-dropdown {
    border: 1px solid var(--primary-gradient-end) !important;
    border-radius: 5px;
    box-shadow: 0 5px 15px rgba(6, 6, 6, 0.2);
}
.select2-container--default.select2-container--focus .select2-selection--single {
    border-color: var(--primary-gradient-end) !important;
    box-shadow: 
        0 0 15px rgba(74, 0, 224, 0.5), 
        inset 0 1px 5px rgba(0, 0, 0, 0.1);
}
.calculate-btn {
    width: 100%;
    padding: 18px 25px;
    background: linear-gradient(90deg, var(--primary-gradient-start) 0%, var(--primary-gradient-end) 100%);
    color: white;
    border: none;
    font-weight: bold;
    border-radius: 10px;
    cursor: pointer;
    font-size: 20px;
    letter-spacing: 1px;
    transition: all 0.3s ease;
    margin-top: 20px;
    box-shadow: 0 10px 25px rgba(74, 0, 224, 0.4);
    position: relative;
    overflow: hidden;
}
.calculate-btn:hover {
    transform: translateY(-2px) scale(1.01);
    box-shadow: 0 15px 30px rgba(74, 0, 224, 0.5);
}
.calculate-btn:active {
    transform: translateY(0) scale(0.99);
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.3);
}
.results-box {
    margin-top: 40px;
    padding-top: 25px;
    border-top: 2px dashed rgba(var(--card-background-rgb), 0.7);
    transition: opacity 0.4s ease-out, transform 0.4s ease-out;
    transform: translateY(0);
}
.results-box.animate-reveal {
    animation: fadeIn 0.8s ease-out;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(15px); }
    to { opacity: 1; transform: translateY(0); }
}
.result-item {
    display: flex;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px dashed #eee;
    font-weight: 500;
}
.result-label {
    font-size: 18px;
    color: var(--sub-text-color);
}
.main-result {
    font-size: 26px;
    color: var(--primary-gradient-end);
    font-weight: 800;
}
.sub-result {
    font-size: 20px;
    color: var(--success-color);
    font-weight: 700;
}
.error-message {
    color: var(--error-color);
    text-align: center;
    font-weight: 700;
    padding: 15px;
    background-color: rgba(255, 230, 230, 0.9);
    border-radius: 8px;
    margin-bottom: 20px;
    border-left: 6px solid var(--error-color);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}
.result-feedback {
    text-align: center;
    margin-top: 20px;
}
.feedback-message {
    font-size: 1.1em;
    font-weight: bold;
    color: var(--primary-gradient-start);
    animation: pulse 1s infinite alternate;
}
@keyframes pulse {
    from { transform: scale(1); opacity: 1; }
    to { transform: scale(1.05); opacity: 0.9; }
}
@media (max-width: 600px) {
    body {
        padding-bottom: 100px;
    }
    .container {
        padding: 25px;
        border-radius: 10px;
    }
    h1 {
        font-size: 28px;
        margin-bottom: 25px;
    }
    h1 i {
        font-size: 24px;
    }
    .form-group label {
        font-size: 14px;
    }
    .form-group input,
    .form-group select {
        padding: 12px;
        font-size: 16px;
    }
    .calculate-btn {
        padding: 15px 15px;
        font-size: 18px;
    }
    .main-result {
        font-size: 22px;
    }
    .sub-result {
        font-size: 18px;
    }
}