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

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: all 0.3s ease;
}

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #f6f8f9 0%, #e5ebee 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.afr-calculator {
    width: 400px;
    background: white;
    border-radius: 25px;
    box-shadow:
        0 15px 35px rgba(0, 0, 0, 0.05),
        0 10px 20px rgba(0, 0, 0, 0.05);
    padding: 30px;
    transform: perspective(1000px) rotateX(-10deg);
    opacity: 0.95;
}

.display {
    background: linear-gradient(145deg, #f0f5f0 0%, #e6f1e6 100%);
    border-radius: 20px;
    padding: 25px;
    box-shadow:
        inset 5px 5px 10px #d1e0d1,
        inset -5px -5px 10px #ffffff;
}

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

label {
    font-weight: 500;
    color: #2c3e50;
    margin-bottom: 8px;
    display: block;
    font-size: 0.9em;
}

input,
select {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e6ed;
    border-radius: 15px;
    font-family: 'Poppins', sans-serif;
    font-size: 0.95em;
    background: #f9fbfc;
    color: #2c3e50;
    outline: none;
    transition: all 0.3s ease;
}

input:focus,
select:focus {
    border-color: #4CAF50;
    box-shadow: 0 0 0 3px rgba(76, 175, 80, 0.2);
}

input::placeholder {
    color: #a0aec0;
    font-weight: 300;
}

#fuelDropdown {
    max-height: 200px;
    overflow-y: auto;
    border-radius: 15px;
    scrollbar-width: thin;
    scrollbar-color: #4CAF50 #e0e6ed;
}

#fuelDropdown::-webkit-scrollbar {
    width: 8px;
}

#fuelDropdown::-webkit-scrollbar-track {
    background: #e0e6ed;
    border-radius: 10px;
}

#fuelDropdown::-webkit-scrollbar-thumb {
    background-color: #4CAF50;
    border-radius: 10px;
}

#fuelDropdown option {
    padding: 10px;
    font-family: 'Poppins', sans-serif;
}

.btn {
    width: 100%;
    padding: 15px;
    border: none;
    border-radius: 20px;
    background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%);
    color: white;
    font-family: 'Poppins', sans-serif;
    font-weight: 600;
    font-size: 1em;
    letter-spacing: 0.5px;
    cursor: pointer;
    box-shadow: 0 10px 20px rgba(76, 175, 80, 0.3);
    transform: translateY(0);
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 25px rgba(76, 175, 80, 0.4);
}

.btn:active {
    transform: translateY(1px);
    box-shadow: 0 5px 10px rgba(76, 175, 80, 0.2);
}

#resultDisplay,
#selectedAFR {
    text-align: center;
    font-weight: 600;
    color: #2c3e50;
    padding: 15px;
    background: rgba(76, 175, 80, 0.1);
    border-radius: 15px;
}

#resultDisplay {
    font-size: 1.3em;
}

#selectedAFR {
    font-size: 1em;
    color: #4CAF50;
}

@media (max-width: 480px) {
    .afr-calculator {
        width: 95%;
        padding: 20px;
        transform: none;
    }
}