style.css

html {
    scroll-behavior: smooth;
}

:root {
    --main-colour: #ff3300;
    --background-colour: #FFF;
    --fore-colour: #222;
    --half-transparent: #0000007C;

    font-size: 62.5%;
}

body {
    font-size: 1.6rem;
    font-family: Consolas;

    min-height: 100vh;

    margin: 0;

    color: var(--fore-colour);
    background-color: var(--background-colour);
}

input,
button {
    font-family: inherit;
}

button {
    cursor: pointer;
}

p,
h1,
h2,
h3 {
    margin: 0;
}

header {
    display: grid;
    grid-template-columns: auto 1fr auto;
    place-content: center;
    place-items: center;
    gap: 5rem;

    padding: 2rem;

    background-color: lightgray;
}

header nav {
    place-self: center start;
}

header nav button {
    padding: 1rem;

    background-color: transparent;

    border: none;
    border-radius: 100rem;
}

header nav button[selected] {
    background-color: darkgray;
}

header nav a {
    text-decoration: none;
    font-size: larger;

    color: inherit;
}

header aside {
    display: flex;
    flex-direction: row;
    place-content: center;
    place-items: center;

    gap: 2rem;
}

header aside button {
    width: 3rem;
    aspect-ratio: 1;

    background-color: transparent;
    background-position: center;
    background-size: 60%;
    background-repeat: no-repeat;

    border: none;
    border-radius: 100%;

    padding: 2rem;
}

header aside #user-container {
    display: flex;
    place-content: center;
    place-items: center;
    gap: 0.5rem;
}

header aside #search-button {
    background-image: url("/images/search.svg");
}

header aside #user-button {
    position: relative;

    background-color: var(--main-colour);
}

header aside #user-button::before {
    content: "";

    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);

    width: 100%;
    aspect-ratio: 1;

    background-image: url("/images/user.svg");
    background-size: 90%;
    background-position: inherit;
    background-position-y: 200%;
    background-repeat: inherit;

    filter: invert();
}

header aside #user-button::after {
    content: attr(notification-number);

    position: absolute;
    top: 0;
    right: 0;
    transform: translate(30%, -30%);

    width: 2rem;
    aspect-ratio: 1;

    display: flex;
    place-content: center;
    place-items: center;

    color: var(--background-colour);
    background-color: orange;

    border-radius: 100%;
}

header aside #user-dropdown-button {
    width: 2rem;

    background-image: url("/images/dropdown.svg");

    padding: 0.5rem;
}

header aside #navbar-button {
    background-image: url("/images/hamburger_button.svg");
}

main {
    display: grid;
    grid-template-columns: 1fr 4fr;
    place-content: center;
    place-items: center;

    padding: 0 5rem;
}

main section {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

main section :is(h1, h2) {
    color: var(--main-colour);
}

main section button {
    font-weight: bold;

    width: 100%;

    padding: 2rem;

    color: var(--background-colour);
    background-color: var(--main-colour);

    border: none;
    border-radius: 100rem;

    box-shadow: 0.8rem 0.8rem 0.2rem var(--half-transparent);
}

main figure {
    display: grid;
    grid-template-columns: 1fr;
    place-content: center;
    place-items: center;
}

main figure embed {
    grid-column: 1;
    grid-row: 1;

    width: calc(100vmin - 8rem);
    aspect-ratio: 1;
}

@media (width < 720px) {
    main {
        display: flex;
        flex-direction: column-reverse;
        place-content: center;
        place-items: center;

        padding-bottom: 5rem;
    }

    main section {
        place-content: center;
        place-items: center;

        width: 50%;
    }
}