:root{
    --bg-color: #F4F5F3;
    --text-color: #001D3E;
    --accent-color: #F7CB2C;
    --light-gray: #DBDDD8;
    --transparent-gray: #FBFBFA;
    --font-main: 'Rethink Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

/* Chrome, Safari, Edge, Opera */
input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Firefox */
input[type=number] {
  -moz-appearance: textfield;
}

body {

    font-family: var(--font-main);

    min-height: 100vh;
    
    line-height: 1.5;
    
    -webkit-font-smoothing: antialiased;
    
    background-color: var(--bg-color); 

    color: var(--text-color);
}

input, button, textarea, select {
    font: inherit;
}

img, picture, video, canvas, svg {
    display: block;
    max-width: 100%;
}

#main-container{
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;   
    display: flex;         
    flex-direction: column;
}

#brand-header{
    width: 100%;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-wrapper{
    width: 2rem;
}

.logo-icon{
    width: 100%;
}

.brand-name{
    font-size: 2rem;
    font-weight: 700;
}

#hero-section{
    margin: 80px auto 20px auto;
    width: 100%;
    text-align: center;
}

.headline{
    font-size: 3rem;
    font-weight: 800;
}

.sub-headline{
    margin: 0 auto;
    font-weight: 400;
    font-size: 20px;
}

#app-interface{
    margin-top: 40px;
}

.tabs-container{
    margin: 0 auto;
    width: fit-content;
    display: flex;
    border: 1px solid var(--light-gray);
    border-radius: 12px;
    padding: 12px;
    gap: 32px;
}

.tab-btn{
    border: none;
    background: none;
    align-items: center;
    min-width: 200px;
    padding: 12px 32px;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    gap: 8px;
}

.tab-btn:not(.active):hover{
    background-color: var(--transparent-gray);
    cursor: pointer;
}

.active{
    background-color: var(--accent-color);
    font-weight: 700;
}

i{
    font-size: 20px;
}

.converter-box{
    margin-top: 64px;
    display: flex;
    width: 100%;
    gap: 40px;
}

.input-group{
    flex: 1;
    display: flex;
    flex-direction: column;
}

.text-unit{
    font-weight: 700;
}

.input-group input{
    width: 100%;
    font-size: 3rem;
    border: 1px solid var(--light-gray);
    background: none;
    border-radius: 12px;
    color: var(--text-color);
    padding: 32px 20px;
    outline: none;
}

input:focus{
    border: 1px solid var(--accent-color);
}

input::placeholder {
  opacity: 0.8;
  color: var(--light-gray);
}

#label-from, #label-to{
    margin-bottom: 12px;
}

.main-footer{
    margin-top: auto;
    text-align: center;
    font-size: .85rem;
    color: var(--text-color);
}

.main-footer a{
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 700;
}




@media screen and (max-width: 729px) {
    .tabs-container{
        flex-wrap: wrap;
        justify-content: center;
        gap: 12px;
    }

    .logo-icon{
        width: 80%;
    }

    .brand-name{
        font-size: 1.5rem;
    }

    .headline{
        font-size: 2rem;
    }

    #hero-section{
        margin-top: 40px;
    }


    .sub-headline{
        font-size: 1rem;
    }

    .converter-box{
        flex-direction: column;
    }

    .main-footer{
        margin-top: 80px;
    }
}