oxygen.css

@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,100..1000;1,9..40,100..1000&display=swap');

:root {
    --color-primary: #e1305f;
    --color-light: #d7d7d7;
    --color-info: #a4a4a4;
    --color-text: #282828;
    --color-border: var(--color-text);
    --color-background: #ffffff;

    --input-width: 300px;
    --form-width: 500px;
    --aside-width: 26%;
    --border-width: 3px;
    --border-radius: 9px;

    --gap: 1rem;
    --tiny-gap: 3px;
    --padding: var(--gap);
    --tiny-padding: calc(var(--padding) * 0.3) calc(var(--padding) * 0.5);
    --input-padding: calc(var(--padding) * 0.6) calc(var(--padding) * 0.8);
}

* {
    font-family: "DM Sans", sans-serif;
    box-sizing: border-box;
    color: var(--color-text);
}

html {

}

body {
    margin: 0;
    padding: 0;
    /*display: flex;*/
}

::selection, ::-moz-selection {
    background-color: var(--color-primary);
    color: var(--color-background);
}

h1 { font-size: 2.8rem; }
h2 { font-size: 2.4rem; }
h3 { font-size: 2rem; }
h4 { font-size: 1.7rem; }
h5 { font-size: 1.4rem; }
h6 { font-size: 1.1rem; }

p {
    font-weight: 500;
}

div.layout {
    display: grid;
}

main {
    width: 100%;
    padding: var(--padding);
}

article {
    padding: var(--padding);
}

section {
    padding: var(--padding);
}

header {
    padding: var(--padding);
}

header:has(nav) {
    padding: 0;
}

footer {
    padding: var(--padding);
}

aside {
    min-width: var(--aside-width);
    width: var(--aside-width);
    padding: var(--padding);
    overflow-y: auto;
    float: left;
}

aside.right {
    float: right;
}

header {
    position: sticky;
    top: 0;
}

article > header, section > header {
    position: static;
    padding: 0;
}

nav {
    border-bottom: var(--border-width) solid var(--color-border);
    padding: var(--padding);
    display: flex;
    gap: calc(var(--gap) * 2);
}

nav * {
    cursor: pointer;
}

nav a {
    text-decoration: none;
    color: var(--color-text);
}

hgroup {
    text-align: center;
}

label {
    display: block;
    padding: var(--tiny-gap) 0;
    font-weight: 600;
    user-select: none;
}

a {
    color: var(--color-primary);
    text-decoration-thickness: var(--border-width);
    font-weight: 700;
}

form {
    width: var(--form-width);
    display: flex;
    flex-direction: column;
    gap: var(--gap);
}

input, select, button, textarea {
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius);
    background-color: var(--color-background);
    outline: none;
    padding: var(--input-padding);
    font-size: 1rem;
    font-family: "DM Sans", sans-serif;
    font-weight: 600;
    min-width: var(--input-width);
    margin: calc(var(--gap) / 2) 0;
    resize: none;
    display: inline-block;
}

textarea.resize {
    resize: both;
}

form input, form select, form textarea, form button {
    width: 100%;
}

button {
    box-shadow: 0 var(--border-width) 0 var(--color-border);
}

button[type='submit'], input[type='submit'] {
    color: var(--color-primary);
    border-color: var(--color-primary);
    font-weight: 700;
    cursor: pointer;
    box-shadow: 0 var(--border-width) 0 var(--color-primary);
}

button:active, input[type='submit']:active {
    animation: 0.3s forwards button_down;
}

input[type='checkbox'], input[type='radio'] {
    min-width: unset;
    border: var(--border-width) solid var(--color-border);
    appearance: none;
    margin: 0;
    width: 16px;
    height: 16px;
    aspect-ratio: 1 / 1;
    padding: 0;
    place-content: center;
    border-radius: calc(var(--border-radius) / 2);
    cursor: pointer;
}

input[type='checkbox']:checked::after, input[type='radio']:checked::after {
    content: "";
    width: 6px;
    height: 6px;
    display: block;
    transition: 120ms transform ease-in-out;
    transform: translateX(2px);
    position: relative;
    background-color: var(--color-primary);
    border-radius: 3px;
}

input[type='radio'] {
    border-radius: var(--border-radius);
}

input[type='radio']:checked::after {
    border-radius: var(--border-radius);
}

::placeholder {
    color: var(--color-info);
    opacity: 1;
    font-weight: 600;
}

fieldset {
    border: var(--border-width) solid var(--color-info);
    border-radius: var(--border-radius);
    display: flex;
    flex-flow: row wrap;
    gap: var(--gap);
    margin: 0;
}

fieldset > legend {
    font-weight: 700;
}

fieldset > label {
    display: flex;
    width: max-content;
    justify-content: center;
    align-items: center;
    gap: var(--tiny-padding);
    cursor: pointer;
}

kbd {

}

code {
    padding: var(--tiny-padding);
    background-color: var(--color-light);
    border-radius: var(--border-radius);
    font-family: monospace;
    font-weight: 600;
}

pre > code {
    white-space: pre-wrap;
    display: block;
    tab-size: 4;
}

details {
    cursor: pointer;
    font-weight: 700;
}

.flex { display: flex; }
.flex.column { flex-direction: column; }

.popup {
    display: none;
    position: absolute;
    z-index: 100;
    top: 0;
    left: 0;
    padding: var(--padding);
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius);
    background-color: var(--color-background);
    gap: var(--gap);
}

.popup.active {
    display: initial;
}

@keyframes button_down {
    0% {
        transform: translateY(0);
    }

    100% {
        box-shadow: none;
        transform: translateY(var(--border-width));
    }
}