Definition collapsing when overflowing (#1575)

* Add double-down-chevron.svg

* Add options

* Update dictionary importers

* Update settings

* Add support for collapsible definitions

* Improve case when there is a very small amount of overflow

* Fix incorrect enabled state of newly imported dictionaries

3 files changed, 111 insertions, 0 deletions

diff --git a/ext/css/display.css b/ext/css/display.css
index 887a04a6..c8669fa2 100644
--- a/ext/css/display.css
+++ b/ext/css/display.css
@@ -101,6 +101,9 @@
     --animation-duration: 0.125s;
     --animation-duration2: calc(2 * var(--animation-duration));
 
+    --collapsible-definition-line-count: 3;
+    --collapsible-definition-test-offset: 0.2em;
+
     /* Colors */
     --background-color: #ffffff;
     --glossary-image-background-color: #eeeeee;
@@ -1154,6 +1157,74 @@ button.action-button[data-icon=source-term]::before {
     opacity: 0;
     white-space: pre-wrap;
 }
+.definition-item {
+    display: list-item;
+    position: relative;
+}
+.definition-item-inner.collapsible.collapsed {
+    max-height: calc(1em * var(--collapsible-definition-line-count) * var(--line-height));
+    overflow: hidden;
+}
+.definition-item-inner.collapse-test {
+    max-height: calc(1em * var(--collapsible-definition-line-count) * var(--line-height) + var(--collapsible-definition-test-offset));
+    overflow: hidden;
+}
+.definition-item-inner {
+    display: flex;
+    flex-flow: row nowrap;
+}
+.definition-item-content {
+    flex: 1 1 auto;
+    background-color: transparent;
+    transition: background-color var(--animation-duration) ease-in-out;
+}
+button.definition-item-expansion-button {
+    --button-content-color: var(--text-color-light4);
+    --button-border-color: transparent;
+    --button-background-color: transparent;
+
+    --button-hover-content-color: var(--text-color-light1);
+    --button-hover-border-color: var(--accent-color-lighter);
+    --button-hover-background-color: var(--accent-color-lighter);
+
+    --button-active-content-color: var(--text-color);
+    --button-active-border-color: var(--accent-color-light);
+    --button-active-background-color: var(--accent-color-light);
+
+    --button-padding-vertical: 0;
+    --button-padding-horizontal: 0.125em;
+
+    flex: 0 0 auto;
+    order: 1;
+    border-radius: 0;
+    border: 0;
+}
+.definition-item-inner:not(.collapsible)>button.definition-item-expansion-button {
+    display: none;
+}
+button.definition-item-expansion-button:hover+.definition-item-content,
+button.definition-item-expansion-button:active+.definition-item-content,
+button.definition-item-expansion-button:focus+.definition-item-content {
+    background-color: var(--accent-color-transparent25);
+}
+button.definition-item-expansion-button:focus:not(:focus-visible)+.definition-item-content {
+    background-color: transparent;
+}
+button.definition-item-expansion-button:focus:hover+.definition-item-content,
+button.definition-item-expansion-button:focus:active+.definition-item-content,
+button.definition-item-expansion-button:focus:focus-visible+.definition-item-content {
+    background-color: var(--accent-color-transparent25);
+}
+.definition-item-expansion-button-icon {
+    transform: rotate(0deg);
+    width: calc(16em / var(--font-size-no-units));
+    height: calc(16em / var(--font-size-no-units));
+    background-color: var(--button-current-content-color);
+    transition: background-color var(--animation-duration) ease-in-out;
+}
+.definition-item-inner.collapsible:not(.collapsed)>button.definition-item-expansion-button>.definition-item-expansion-button-icon {
+    transform: rotate(180deg);
+}
 
 
 /* Frequencies */
diff --git a/ext/css/material.css b/ext/css/material.css
index 703f1268..08345769 100644
--- a/ext/css/material.css
+++ b/ext/css/material.css
@@ -234,6 +234,7 @@
 .icon[data-icon=question-mark-thick]     { --icon-image: url(/images/question-mark-thick.svg); }
 .icon[data-icon=left-chevron]            { --icon-image: url(/images/left-chevron.svg); }
 .icon[data-icon=right-chevron]           { --icon-image: url(/images/right-chevron.svg); }
+.icon[data-icon=double-down-chevron]     { --icon-image: url(/images/double-down-chevron.svg); }
 .icon[data-icon=plus-thick]              { --icon-image: url(/images/plus-thick.svg); }
 .icon[data-icon=clipboard]               { --icon-image: url(/images/clipboard.svg); }
 .icon[data-icon=key]                     { --icon-image: url(/images/key.svg); }
diff --git a/ext/css/settings.css b/ext/css/settings.css
index e2485925..22439409 100644
--- a/ext/css/settings.css
+++ b/ext/css/settings.css
@@ -47,6 +47,7 @@
     --outline-item-icon-size: 32px;
     --input-short-width: calc(var(--input-width-large) / 2 - var(--padding) / 2);
     --input-short-height: 24px;
+    --input-medium-width: calc(var(--input-width-large) * 0.75);
     --fab-button-size: 56px;
     --fab-button-padding: 16px;
     --modal-width: 600px;
@@ -657,6 +658,11 @@ input[type=number].short-width,
 select.short-width {
     width: var(--input-short-width);
 }
+input[type=text].medium-width,
+input[type=number].medium-width,
+select.medium-width {
+    width: var(--input-medium-width);
+}
 input[type=text].short-height,
 input[type=number].short-height,
 select.short-height {
@@ -2125,6 +2131,39 @@ button.hotkey-list-item-enabled-button[data-scope-count='0'] {
     background-color: var(--warning-color);
 }
 
+.collapsible-dictionary-list {
+    width: 100%;
+    display: flex;
+    flex-flow: column nowrap;
+    align-items: stretch;
+}
+.collapsible-dictionary-item {
+    display: flex;
+    flex-flow: row nowrap;
+    align-items: center;
+    margin-left: calc(var(--modal-padding-horizontal) * -1);
+    margin-right: calc(var(--modal-padding-horizontal) * -1);
+    padding: var(--settings-group-inner-horizontal-padding-fourth) var(--modal-padding-horizontal);
+}
+.collapsible-dictionary-item:not(:first-child) {
+    border-top: var(--thin-border-size) solid var(--separator-color2);
+}
+.collapsible-dictionary-cell {
+    display: flex;
+    flex-flow: row nowrap;
+    align-items: center;
+}
+.collapsible-dictionary-cell:first-of-type {
+    flex: 1 1 auto;
+}
+.collapsible-dictionary-cell:not(:first-of-type) {
+    flex: 0 0 auto;
+    margin-left: 1em;
+}
+.collapsible-dictionary-cell-label {
+    margin-left: 0.375em;
+}
+
 
 /* Generic layouts */
 .margin-above {