* {
    font-family: sans-serif;
    font-size: 24px;
    font-weight: bolder;
}

.slider {
    writing-mode: vertical-lr;
    direction: rtl;
    vertical-align: middle;
    font-size: 10px;
}

.estate {
    width: 100px;
    align-self: center;
    text-align: right;
    color: blue;
}

.container {
    display: flex;
    gap: 30px;
}

.claimant {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.number {
    width: 100px;
    height: 2em;
    line-height: 2em;
    margin-bottom: 15px;
    text-align: center;
    font-size: inherit;
}

.tank {
    background: linear-gradient(to top, blue var(--water-level), white var(--water-level));
    display: flex;
    align-items: center;
    flex-direction: column;
    flex-grow: 1;
}

.tank > * {
    width: 100px;
    border: 3px solid black;
    transition: height .3s;
}

.tank .top {
    border-bottom: none;
}

.tank .bot {
    border-top: none;
}

.tank .mid {
    flex-grow: 1;
    border-top: none;
    border-bottom: none;
    border: none;
    position: relative;
}

.tank .mid::before, .tank .mid::after {
    content: "";
    background: white;
    border: 3px solid black;
    position: absolute;
    top: 0;
    bottom: 0;
    width: calc(100% / 2 - 1.5px);
}

.tank .mid::before {
    left: -3px;
    border-left: none;
}

.tank .mid::after {
    right: -3px;
    border-right: none;
}

.add {
    width: 40px;
    height: 40px;
    align-self: center;
}