:root {
    /* base */
    --primary: #1e3a8a;

    /* dark blue */
    --accent: #3b82f6;
    --background: #273b57;
    --input-bg: #1e293b;

    /* bright blue */
    --neutral: #f5f5f5;
    --dark-bg: #0f172a;

    /* light gray */
    --text-light: #e2e8f0;

    /* dark mode */
    --text-dark: #1f2937;
    
    /* button */
    --button-background: #2398ff;
    --button-hover: #145a97;
    --buttom-active: #003569;

    /* borders and shadows */
    --radius: 10px;
    --shadow: 0 4px 10px rgba(0, 0, 0, 0.473);

    /* text */
    --font-main: sans-serif;
}

body {
    font-family: var(--font-main);
    background-color: var(--dark-bg);
    color: var(--text-light);
    display: flex;
    justify-content: center;
    margin: 0;
    min-height: 100vh;
    align-items: flex-start;
    padding: 2rem 0;
}

.converter{
    background: var(--primary);
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    width: 90%;
    max-width: 400px;
}

input, button{
    width: 100%;
    padding: 0.8rem;
    margin-top: 0.5rem;
    border: none;
    border-radius: var(--radius);
}

input {
    background: var(--input-bg);
    color: var(--text-light)
}

select {
    margin-top: 0.5rem;
    padding: 0.8rem;
    background-color: var(--background);
    border: 0;
    border-radius: var(--radius);
    font-size: 0.875rem;
    color: var(--text-light);
    cursor: pointer;
    transition: all 0.2s;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.5rem center;
    padding-right: 2.5rem;
}

select:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

select:hover {
    background-color: var(--button-hover);
    color: white;
}

button {
    background: var(--button-background);
    color: white;
    font-weight: bold;
    cursor: pointer;
    transition: 0.2s;
}

button:hover{
    background: var(--button-hover);
}

button:active{
    background: var(--buttom-active);
    box-shadow: var(--shadow);
}

#result {
    margin-top: 1rem;
    font-size: 1.2rem;
    color: var(--accent);
}

@media screen and (min-width: 625px){
    .converter{
        width: 90%;
        max-width: 700px;
    }
}