forgejo/web_src/css/modules/dropdown.css

/* Copyright 2025 The Forgejo Authors. All rights reserved.
 * SPDX-License-Identifier: GPL-3.0-or-later */

/* This is an implementation of a dropdown menu based on details HTML tag.
 * It is inspired by https://picocss.com/docs/dropdown.
 *
 * NoJS mode could be improved by forcing the same [name] onto all dropdowns, so
 * that the browser will automatically close all but the one that was just opened
 * using keyboard. But the code doing that will not be as clean.
 *
 * Note: when implementing this dropdown, please use `dropdown` as the 1st class,
 * so it is possible to search for all dropdowns with `details class="dropdown`
*/

:root details.dropdown {
  --dropdown-box-shadow: 0 6px 18px var(--color-shadow);
  --dropdown-item-min-height: 34px;
  --dropdown-padding-inline: 0.75rem;
}

@media (pointer: coarse) {
  :root details.dropdown {
    --dropdown-item-min-height: 40px;
    --dropdown-padding-inline: 1rem;
  }
}

details.dropdown {
  position: relative;
}

/* Opener */
details.dropdown > summary {
  /* Optional flex+gap in case summary contains multiple elements */
  display: flex;
  gap: 0.25rem;
  align-items: center;
  justify-content: center;
  /* Main visual properties */
  border-radius: var(--border-radius);
  padding: 0.5rem;
  /* Unset unwanted default properties */
  user-select: none;
  list-style-type: none;

  /* Display a border around opener */
  &.border {
    border: 1px solid var(--color-light-border);
  }
  /* Increase inline padding - for openers with text, like filter menus */
  &.options {
    padding-inline: 0.75rem;
  }
}

/* NoJS mode: create a virtual fullscreen area which closes the dropdown when clicked on */
.no-js details.dropdown[open] > summary::before {
  z-index: 1;
  position: fixed;
  width: 100vw;
  height: 100vh;
  inset: 0;
  background: 0 0;
  content: "";
  cursor: default;
}

details.dropdown > summary:hover,
details.dropdown > .content > ul > li > :is(a, button):hover {
  background: var(--color-hover);
}

details.dropdown[open] > summary,
details.dropdown > .content > ul > li:focus-within > :is(a, button) {
  background: var(--color-active);
}

details.dropdown > .content {
  z-index: 99;
  position: absolute;
  min-width: max-content;
  border-radius: var(--border-radius);
  background: var(--color-body);
  box-shadow: var(--dropdown-box-shadow);
  border: 1px solid var(--color-secondary);
  margin-top: 0.5rem;

  /* ToDo: upstream to base.css, remove from normalize.css */
  hr {
    height: 1px;
    margin-block: 0.25rem;
    background-color: var(--color-secondary);
  }
}

details.dropdown > .content > ul {
  /* Suppress default styling of <ul> */
  margin: 0;
  padding: 0;
  list-style-type: none;

  /* Round first item of first list and last item of last list. Each of these
   * selectors should only resolve to one element in any .content */
  &:first-of-type > li:first-child {
    border-radius: var(--border-radius) var(--border-radius) 0 0;
  }
  &:last-of-type > li:last-child {
    border-radius: 0 0 var(--border-radius) var(--border-radius);
  }
}

/* General styling of list items */
details.dropdown > .content > ul > li {
  width: 100%;

  > :is(a, button) {
    min-height: var(--dropdown-item-min-height);
    padding-block: 0;

    width: 100%;
    padding-inline: var(--dropdown-padding-inline);
    display: flex;
    gap: 0.75rem;
    align-items: center;
    color: var(--color-text);

    /* Interactable items should be transparent by default. <button> can also have a default background set by the browser */
    background: none;

    /* Same rounding should apply to both <li> and it's items with paintable backgrounds */
    border-radius: inherit;

    /* Suppress underline - hover is indicated by background color */
    text-decoration: none;

    /* Items that are pre-selected in template or by JS */
    &.active {
      background: var(--color-active);
      font-weight: var(--font-weight-medium);
    }
  }
}

/* Special styling for "headers" */
/* A few dropdowns contain such headers, however, they are not semantically considered as headers */
details.dropdown > .content > .header {
  display: flex;
  padding-block: 0.5rem;
  padding-inline: var(--dropdown-padding-inline);
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
  font-size: 0.8rem;
}

/* Decrease bottom padding if an <hr> follows, which adds it's own vertical padding */
details.dropdown > .content > .header:has(+ hr) {
  padding-bottom: 0.25rem;
}

/* dir-auto option - switch the direction at a width point where most of layout changes occur */
@media (max-width: 767.98px) {
  details.dropdown.dir-auto > .content {
    inset-inline: 0 auto;
    direction: rtl;
    > :is(span, ul) {
      direction: ltr;
    }
  }
}

/* dir-rtl option - force right-to-left box direction */
details.dropdown.dir-rtl > .content {
  inset-inline: 0 auto;
  direction: rtl;
  > :is(span, ul) {
    direction: ltr;
  }
}

/* Note: CSS anchor positioning will be a huge help in content positioning w/o JS
 * - https://css-tricks.com/css-anchor-positioning-guide/
 * - https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_anchor_positioning/
 * - https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_anchor_positioning/Using
 * It can already be implemented if the implementation won't interfere with the
 * normal behavior on unsupported browsers. Or it can wait until Firefox gets
 * starts supporting it. FF145 got this feature behind a feature flag. */