body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    font-size: 100%;
    line-height: 1.5em;
    margin: 0;
    background-color: #121212;
    color: aliceblue;
}

header {
    min-height: 40vh;
    background-color: #515151;
    display: flex;
    flex-direction: column;
    background-image: url(http://images.webwork.space/576x448/window09.jpg);
    /* background: linear-gradient(rgba(0,0,0,0.75),rgb(0,0,0,0.75)), url("http://images.webwork.space/576x448/window09.jpg"); */
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
    position: relative;
}

h1 {
    font-weight: 300;
    font-size: 2.5em;
    line-height: 1.2em;
    /* text-align: center; */
    padding-top: 2%;
    padding-left: 2vw;
    z-index: 1;
}

/* h1::before {
    content: " ";
    height: 40vh;
    width: 100%;
    backdrop-filter: blur(10px);
    position: absolute;
    top: 0;
    left: 0;
    z-index: -1;
} */

.mobile-br {
    display: none;
}

main {
    column-width: 15em;
    column-gap: 1em;
    margin: 2em 1em;
    /* column-rule: 1px dotted #aaa; */
}

/* the special syntax below ">*" means any direct child of the class */

main>* {
    margin-top: 0;
    margin-bottom: 1.5em;
}

@media screen and (max-width: 430px) {
    h1 {
        padding: 0 0 0 0.6em;
    }

    .mobile-br {
        display: block;
    }

    .normal-br {
        display: none;
    }
}