body {
    margin: 0;
    padding: 100px;
    min-height: 100vh;
    background:
        repeating-linear-gradient(transparent, transparent 20px, deepskyblue 22px),
        repeating-linear-gradient(90deg,
            transparent, transparent 20px, deepskyblue 22px),
        linear-gradient(to left, transparent 2cm, red calc(2cm + 3px), transparent 2cm);
    border: 2px solid deepskyblue;
    box-sizing: border-box;
    font-size: 18px;
}

body h1:first-child {
    margin-top: 0;
    font-weight: normal;
}

a {
    color: darkblue;
}

table#list {
    width: auto;
}

iframe[seamless] {
    border: none;
}

div.content {
    margin: 0 auto;
    width: fit-content;
}

p {
    padding: 8px;
    line-height: 1.5;
}

ul,
p,
table {
    background-color: rgba(255, 255, 255, 0.88);
    border-radius: 10px;
    border: 1px solid #aaa;
    padding-right: 10px;
}

ul li {
    line-height: 2.33;
}

img.messenger {
    height: 24px;
}

img.myphoto {
    height: 88px;
}