* {
    box-sizing: border-box;
}

:root {
    --active-border-color: rgb(0, 110, 255);
    --not-active-border-color: rgb(128, 128, 128);
}

body {
    font-family: Arial, Helvetica, sans-serif;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: rgb(54, 54, 54);
    height: 100vh;
}

.container {
    text-align: center;
}

.progress-container {
    display: flex;
    justify-content: space-between;
    position: relative;
    margin-bottom: 1vh;
    width: 35vw;
}

.progress-container::before {
    content: '';
    background-color: var(--not-active-border-color);
    position: absolute;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
    height: 4px;
    width: 100%;
    z-index: -1;
}

.progress {
    background-color: var(--active-border-color);
    position: absolute;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
    height: 4px;
    width: 0%;
    z-index: -1;
    transition: 0.7s ease;
}

.circle {
    background-color: white;
    color: gray;
    border-radius: 50%;
    height: 30px;
    width: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 3px solid var(--not-active-border-color);
    transition: 0.4s ease;
}

.circle.active {
    border-color: var(--active-border-color);
}

.btn {
    background-color: var(--active-border-color);
    color: white;
    border: 0;
    border-radius: 5px;
    cursor: pointer;
    font-family: inherit;
    padding: 1vh 3vh;
    margin: 5px;
    font-size: 16px;
}

.btn:active {
    transform: scale(0.95);
    background-color: var(--active-border-color);
}

.btn:focus {
    outline: 0;
}

.btn:disabled {
    background-color: var(--not-active-border-color);
    cursor: not-allowed;
}