下拉弹层改视口定位，规则表单换 ComboBox

absolute 的弹层会计入祖先滚动容器的可滚动区域——在对话框里打开下拉，
modal 会被撑出滚动条。弹层改 position: fixed 按视口摆放：逃出所有
overflow 裁剪，又因为还在 dialog 的 DOM 子树里，照样画在 top layer 之上。
代价是位置不跟随滚动，滚动和缩放时直接收起（弹层内部滚动不算）。
三个弹层组件（SelectBox、ComboBox、SourcePicker）同一套做法。

组件根元素不再写死 width: 100%：它和调用方的宽度规则同权重，谁赢
看样式表加载顺序——请求页的级别下拉被撑满整行就是这么来的。
弹层加 user-select: none 和最大宽度，选项超长省略号截断。

规则表单的类型、载荷、目标原来是 input + datalist，原生建议列表的样式
和开合状态都管不到，换成同族的 ComboBox：选项只是建议、手填合法，
Enter 在弹层开着时选中高亮项、收起时照旧提交表单。

web/components/ComboBox.vue

@@ -0,0 +1,278 @@
+<script setup lang="ts">
+/**
+ * 可自由填写的组合框，替代原生 input + datalist。
+ *
+ * 和 SelectBox 的分工：SelectBox 的值只能从选项里挑；这里选项只是建议，
+ * 手填任何值都合法（规则的目标可以是候选之外的出站名）。换掉 datalist
+ * 的理由和 SelectBox 一样：原生建议列表的样式、动画、开合状态都管不到。
+ *
+ * Enter 的归属：弹层开着且有高亮项时选中它、不提交表单；弹层收起时不拦，
+ * 交给对话框的表单提交——填完直接回车保存是原生 input 的习惯，不能破坏。
+ */
+import { computed, onBeforeUnmount, ref, watch } from 'vue'
+import IconChevron from '~icons/ri/arrow-down-s-line'
+
+const props = defineProps<{
+  /** 建议列表。过滤是 includes，不区分大小写 */
+  options: string[]
+  placeholder?: string
+  /** 等宽字体，规则原文这类内容用 */
+  mono?: boolean
+  ariaLabel?: string
+}>()
+
+const text = defineModel<string>({ default: '' })
+
+const root = ref<HTMLElement | null>(null)
+const input = ref<HTMLInputElement | null>(null)
+const menuEl = ref<HTMLElement | null>(null)
+const open = ref(false)
+const openUp = ref(false)
+const active = ref(0)
+const menuStyle = ref<Record<string, string>>({})
+
+const filtered = computed(() => {
+  const q = text.value.trim().toLowerCase()
+  if (!q) return props.options
+  return props.options.filter((name) => name.toLowerCase().includes(q))
+})
+
+const MENU_ROOM = 220
+
+/**
+ * 弹层是 position: fixed，按视口摆放，理由同 SelectBox：absolute 会计入
+ * 祖先滚动容器的可滚动区域，在对话框里打开会把对话框撑出滚动条。
+ * 位置不跟随滚动，所以滚动和缩放时直接收起。
+ */
+function place() {
+  const rect = root.value?.getBoundingClientRect()
+  if (!rect) return
+  const up = window.innerHeight - rect.bottom < MENU_ROOM && rect.top > MENU_ROOM
+  openUp.value = up
+  menuStyle.value = {
+    left: `${String(rect.left)}px`,
+    minWidth: `${String(rect.width)}px`,
+    ...(up
+      ? { bottom: `${String(window.innerHeight - rect.top + 4)}px` }
+      : { top: `${String(rect.bottom + 4)}px` }),
+  }
+}
+
+/** 页面或对话框一滚动，锚点就不准了，直接收起。弹层内部的滚动不算 */
+function closeOnMove(event?: Event) {
+  if (event?.target instanceof Node && menuEl.value?.contains(event.target)) return
+  open.value = false
+}
+
+watch(open, (isOpen) => {
+  if (isOpen) {
+    window.addEventListener('scroll', closeOnMove, true)
+    window.addEventListener('resize', closeOnMove)
+  } else {
+    window.removeEventListener('scroll', closeOnMove, true)
+    window.removeEventListener('resize', closeOnMove)
+  }
+})
+
+onBeforeUnmount(() => {
+  window.removeEventListener('scroll', closeOnMove, true)
+  window.removeEventListener('resize', closeOnMove)
+})
+
+function show() {
+  active.value = 0
+  place()
+  open.value = true
+}
+
+function onInput() {
+  show()
+}
+
+function toggleFromChevron() {
+  if (open.value) open.value = false
+  else show()
+  input.value?.focus()
+}
+
+function pick(name: string) {
+  text.value = name
+  open.value = false
+  input.value?.focus()
+}
+
+function onKeydown(event: KeyboardEvent) {
+  if (event.key === 'ArrowDown' || event.key === 'ArrowUp') {
+    event.preventDefault()
+    if (!open.value) {
+      show()
+      return
+    }
+    const count = filtered.value.length
+    if (count === 0) return
+    const delta = event.key === 'ArrowDown' ? 1 : -1
+    active.value = (active.value + delta + count) % count
+  } else if (event.key === 'Enter') {
+    if (!open.value) return // 交给表单提交
+    const name = filtered.value[active.value]
+    event.preventDefault()
+    if (name) pick(name)
+    else open.value = false
+  } else if (event.key === 'Escape' && open.value) {
+    event.stopPropagation()
+    event.preventDefault()
+    open.value = false
+  }
+}
+
+function onFocusOut(event: FocusEvent) {
+  const next = event.relatedTarget
+  if (next instanceof Node && root.value?.contains(next)) return
+  open.value = false
+}
+</script>
+
+<template>
+  <div ref="root" class="combo" @focusout="onFocusOut">
+    <input
+      ref="input"
+      v-model="text"
+      :class="['field', mono && 'mono']"
+      type="text"
+      role="combobox"
+      :aria-expanded="open"
+      :aria-label="ariaLabel"
+      :placeholder="placeholder"
+      autocomplete="off"
+      spellcheck="false"
+      @focus="show"
+      @input="onInput"
+      @keydown="onKeydown"
+    />
+    <button
+      type="button"
+      class="toggle"
+      :aria-label="open ? '收起建议' : '展开建议'"
+      tabindex="-1"
+      @click="toggleFromChevron"
+    >
+      <IconChevron :class="['chev', open && 'is-open']" aria-hidden="true" />
+    </button>
+
+    <Transition name="menu">
+      <ul
+        v-if="open && filtered.length > 0"
+        ref="menuEl"
+        :class="['menu', openUp && 'is-up']"
+        :style="menuStyle"
+        role="listbox"
+      >
+        <li v-for="(name, i) in filtered" :key="name">
+          <button
+            type="button"
+            role="option"
+            :aria-selected="name === text"
+            :class="['opt', i === active && 'is-active']"
+            @mousemove="active = i"
+            @click="pick(name)"
+          >
+            {{ name }}
+          </button>
+        </li>
+      </ul>
+    </Transition>
+  </div>
+</template>
+
+<style scoped>
+.combo {
+  position: relative;
+}
+
+.field {
+  width: 100%;
+  padding: var(--s-2) var(--s-3);
+  /* 给右侧箭头留位置 */
+  padding-right: var(--s-6);
+  border: 1px solid var(--c-border-strong);
+  border-radius: var(--r-sm);
+  background: var(--select-bg, var(--c-bg));
+}
+
+.toggle {
+  position: absolute;
+  top: 0;
+  right: 0;
+  bottom: 0;
+  display: flex;
+  align-items: center;
+  padding: 0 var(--s-2);
+  border: none;
+  background: none;
+  color: var(--c-text-faint);
+  cursor: pointer;
+}
+
+.chev {
+  width: 16px;
+  height: 16px;
+  transition: transform 0.2s ease;
+}
+
+.chev.is-open {
+  transform: rotate(180deg);
+}
+
+/* 位置（left/top/bottom/minWidth）由 place() 以内联样式给出 */
+.menu {
+  position: fixed;
+  z-index: 1;
+  max-width: min(360px, calc(100vw - 2 * var(--s-4)));
+  max-height: 200px;
+  overflow-y: auto;
+  list-style: none;
+  margin: 0;
+  padding: var(--s-1);
+  border: 1px solid var(--c-border-strong);
+  border-radius: var(--r-md);
+  background: var(--c-surface);
+  user-select: none;
+}
+
+.opt {
+  display: block;
+  width: 100%;
+  padding: var(--s-2) var(--s-3);
+  border: none;
+  border-radius: var(--r-sm);
+  background: none;
+  text-align: left;
+  font-size: var(--t-sm);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  cursor: pointer;
+}
+
+.opt.is-active {
+  background: var(--c-surface-sunken);
+}
+
+.menu-enter-active,
+.menu-leave-active {
+  transition:
+    opacity 0.12s ease,
+    transform 0.12s ease;
+}
+
+.menu-enter-from,
+.menu-leave-to {
+  opacity: 0;
+  transform: translateY(-4px);
+}
+
+.menu.is-up.menu-enter-from,
+.menu.is-up.menu-leave-to {
+  transform: translateY(4px);
+}
+</style>

web/components/SelectBox.vue

@@ -9,7 +9,7 @@
  * 背景色用 --select-bg 变量留了口子：对话框里的控件要比对话框底色沉一档
  * （--c-bg），页面上的控件要比页面底色浮一档（--c-surface），一个值满足不了。
  */
-import { computed, ref } from 'vue'
+import { computed, onBeforeUnmount, ref, watch } from 'vue'
 import IconCheck from '~icons/ri/check-line'
 import IconChevron from '~icons/ri/arrow-down-s-line'
 
@@ -31,15 +31,37 @@ const props = defineProps<{
 const chosen = defineModel<string>({ default: '' })
 
 const root = ref<HTMLElement | null>(null)
+const menuEl = ref<HTMLElement | null>(null)
 const open = ref(false)
 /** 往上弹。下方视口不够放弹层、上方够时翻转，不把弹层怼出屏幕 */
 const openUp = ref(false)
 const active = ref(0)
+const menuStyle = ref<Record<string, string>>({})
 
 const current = computed(() => props.options.find((o) => o.value === chosen.value) ?? null)
 
 const MENU_ROOM = 220
 
+/**
+ * 弹层是 position: fixed，按视口摆放。absolute 的弹层会计入祖先滚动容器的
+ * 可滚动区域——在对话框里打开就把对话框撑出滚动条。fixed 逃出所有 overflow
+ * 裁剪，又因为还在 dialog 的 DOM 子树里，照样画在 top layer 之上。
+ * 代价是位置不跟随滚动，所以下面在滚动和缩放时直接收起。
+ */
+function place() {
+  const rect = root.value?.getBoundingClientRect()
+  if (!rect) return
+  const up = window.innerHeight - rect.bottom < MENU_ROOM && rect.top > MENU_ROOM
+  openUp.value = up
+  menuStyle.value = {
+    left: `${String(rect.left)}px`,
+    minWidth: `${String(rect.width)}px`,
+    ...(up
+      ? { bottom: `${String(window.innerHeight - rect.top + 4)}px` }
+      : { top: `${String(rect.bottom + 4)}px` }),
+  }
+}
+
 function toggleOpen() {
   if (open.value) {
     open.value = false
@@ -49,11 +71,31 @@ function toggleOpen() {
     0,
     props.options.findIndex((o) => o.value === chosen.value),
   )
-  const rect = root.value?.getBoundingClientRect()
+  place()
-  openUp.value = !!rect && window.innerHeight - rect.bottom < MENU_ROOM && rect.top > MENU_ROOM
   open.value = true
 }
 
+/** 页面或对话框一滚动，锚点就不准了，直接收起。弹层内部的滚动不算 */
+function closeOnMove(event?: Event) {
+  if (event?.target instanceof Node && menuEl.value?.contains(event.target)) return
+  open.value = false
+}
+
+watch(open, (isOpen) => {
+  if (isOpen) {
+    window.addEventListener('scroll', closeOnMove, true)
+    window.addEventListener('resize', closeOnMove)
+  } else {
+    window.removeEventListener('scroll', closeOnMove, true)
+    window.removeEventListener('resize', closeOnMove)
+  }
+})
+
+onBeforeUnmount(() => {
+  window.removeEventListener('scroll', closeOnMove, true)
+  window.removeEventListener('resize', closeOnMove)
+})
+
 function pick(value: string) {
   chosen.value = value
   open.value = false
@@ -119,7 +161,7 @@ function groupAt(index: number): string | null {
     </button>
 
     <Transition name="menu">
-      <ul v-if="open" :class="['menu', openUp && 'is-up']" role="listbox">
+      <ul v-if="open" ref="menuEl" :class="['menu', openUp && 'is-up']" :style="menuStyle" role="listbox">
         <li v-if="options.length === 0" class="none">没有可选项</li>
         <template v-for="(item, i) in options" :key="item.value">
           <li v-if="groupAt(i)" class="group" role="presentation">{{ groupAt(i) }}</li>
@@ -143,9 +185,10 @@ function groupAt(index: number): string | null {
 </template>
 
 <style scoped>
+/* 宽度不在这里定：块级元素在表单列里自然撑满，行内布局由调用方给定宽度。
+   写死 width: 100% 会和调用方的宽度规则打架，两条同权重规则谁赢看加载顺序 */
 .select {
   position: relative;
-  width: 100%;
 }
 
 .face {
@@ -159,6 +202,7 @@ function groupAt(index: number): string | null {
   background: var(--select-bg, var(--c-bg));
   text-align: left;
   cursor: pointer;
+  user-select: none;
 }
 
 /* 和文本输入一致：焦点态是描边变色，不叠外圈 */
@@ -190,12 +234,12 @@ function groupAt(index: number): string | null {
   transform: rotate(180deg);
 }
 
+/* 位置（left/top/bottom/minWidth）由 place() 以内联样式给出 */
 .menu {
-  position: absolute;
+  position: fixed;
   z-index: 1;
-  top: calc(100% + var(--s-1));
+  /* 弹层可以比控件宽（按最长选项撑开），但不能宽出屏幕 */
-  left: 0;
+  max-width: min(360px, calc(100vw - 2 * var(--s-4)));
-  min-width: 100%;
   max-height: 200px;
   overflow-y: auto;
   list-style: none;
@@ -204,11 +248,7 @@ function groupAt(index: number): string | null {
   border: 1px solid var(--c-border-strong);
   border-radius: var(--r-md);
   background: var(--c-surface);
-}
+  user-select: none;
-
-.menu.is-up {
-  top: auto;
-  bottom: calc(100% + var(--s-1));
 }
 
 .group {
@@ -229,6 +269,8 @@ function groupAt(index: number): string | null {
   text-align: left;
   font-size: var(--t-sm);
   white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
   cursor: pointer;
 }
 

web/components/SourcePicker.vue

@@ -7,7 +7,7 @@
  * 标签收在框内、下拉列出全部选项并给已选的打勾、点击不收起。订阅只有一两个时
  * 平铺标签更直接，但数量一多平铺就是一面墙，这个形态两头都撑得住。
  */
-import { computed, ref, watch } from 'vue'
+import { computed, nextTick, onBeforeUnmount, ref, watch } from 'vue'
 import IconCheck from '~icons/ri/check-line'
 import IconRemove from '~icons/ri/close-line'
 
@@ -16,10 +16,13 @@ const chosen = defineModel<string[]>({ required: true })
 
 const root = ref<HTMLElement | null>(null)
 const input = ref<HTMLInputElement | null>(null)
+const menuEl = ref<HTMLElement | null>(null)
 const open = ref(false)
+const openUp = ref(false)
 const query = ref('')
 /** 键盘上下键在过滤结果里走到第几项 */
 const active = ref(0)
+const menuStyle = ref<Record<string, string>>({})
 
 const filtered = computed(() =>
   props.options.filter((name) => name.toLowerCase().includes(query.value.trim().toLowerCase())),
@@ -30,16 +33,62 @@ watch(query, () => {
   open.value = true
 })
 
+const MENU_ROOM = 220
+
+/**
+ * 弹层是 position: fixed，按视口摆放，理由同 SelectBox：absolute 会计入
+ * 祖先滚动容器的可滚动区域，把页面或对话框撑出滚动条。
+ * 位置不跟随滚动，所以滚动和缩放时直接收起。
+ */
+function place() {
+  const rect = root.value?.getBoundingClientRect()
+  if (!rect) return
+  const up = window.innerHeight - rect.bottom < MENU_ROOM && rect.top > MENU_ROOM
+  openUp.value = up
+  menuStyle.value = {
+    left: `${String(rect.left)}px`,
+    minWidth: `${String(rect.width)}px`,
+    ...(up
+      ? { bottom: `${String(window.innerHeight - rect.top + 4)}px` }
+      : { top: `${String(rect.bottom + 4)}px` }),
+  }
+}
+
+/** 页面一滚动锚点就不准了，直接收起。弹层内部的滚动不算 */
+function closeOnMove(event?: Event) {
+  if (event?.target instanceof Node && menuEl.value?.contains(event.target)) return
+  open.value = false
+}
+
+watch(open, (isOpen) => {
+  if (isOpen) {
+    place()
+    window.addEventListener('scroll', closeOnMove, true)
+    window.addEventListener('resize', closeOnMove)
+  } else {
+    window.removeEventListener('scroll', closeOnMove, true)
+    window.removeEventListener('resize', closeOnMove)
+  }
+})
+
+onBeforeUnmount(() => {
+  window.removeEventListener('scroll', closeOnMove, true)
+  window.removeEventListener('resize', closeOnMove)
+})
+
 function toggle(name: string) {
   chosen.value = chosen.value.includes(name)
     ? chosen.value.filter((item) => item !== name)
     : [...chosen.value, name]
   // 点完一项接着挑下一项，不用再点回输入框
   input.value?.focus()
+  // 标签增减会改变输入框高度，锚点变了要重新摆
+  void nextTick(place)
 }
 
 function remove(name: string) {
   chosen.value = chosen.value.filter((item) => item !== name)
+  if (open.value) void nextTick(place)
 }
 
 function onKeydown(event: KeyboardEvent) {
@@ -93,7 +142,14 @@ function onFocusOut(event: FocusEvent) {
     </div>
 
     <Transition name="menu">
-      <ul v-if="open" class="menu" role="listbox" aria-multiselectable="true">
+      <ul
+        v-if="open"
+        ref="menuEl"
+        :class="['menu', openUp && 'is-up']"
+        :style="menuStyle"
+        role="listbox"
+        aria-multiselectable="true"
+      >
       <li v-if="options.length === 0" class="none">没有可选的订阅</li>
       <li v-else-if="filtered.length === 0" class="none">没有匹配的订阅</li>
       <li v-for="(name, i) in filtered" :key="name">
@@ -175,13 +231,11 @@ function onFocusOut(event: FocusEvent) {
   font-size: var(--t-sm);
 }
 
-/* 浮在上面，不能把下面几行顶下去 */
+/* 浮在上面，不能把下面几行顶下去。位置由 place() 以内联样式给出 */
 .menu {
-  position: absolute;
+  position: fixed;
   z-index: 1;
-  top: calc(100% + var(--s-1));
+  max-width: min(360px, calc(100vw - 2 * var(--s-4)));
-  left: 0;
-  min-width: 100%;
   max-height: 240px;
   overflow-y: auto;
   list-style: none;
@@ -190,6 +244,7 @@ function onFocusOut(event: FocusEvent) {
   border: 1px solid var(--c-border-strong);
   border-radius: var(--r-md);
   background: var(--c-surface);
+  user-select: none;
 }
 
 .opt {
@@ -240,4 +295,9 @@ function onFocusOut(event: FocusEvent) {
   opacity: 0;
   transform: translateY(-4px);
 }
+
+.menu.is-up.menu-enter-from,
+.menu.is-up.menu-leave-to {
+  transform: translateY(4px);
+}
 </style>

web/views/RuleForm.vue

@@ -9,6 +9,7 @@
  */
 import { computed, ref, watch } from 'vue'
 import { buildRule, isStructuredEditable, parseRule } from '@shared/rules.ts'
+import ComboBox from '../components/ComboBox.vue'
 import IconClose from '~icons/ri/close-line'
 
 const props = defineProps<{
@@ -143,45 +144,36 @@ function submit() {
         <label class="row">
           <span class="k">类型</span>
           <span class="v">
-            <input v-model="type" class="mono" type="text" list="rule-types" autocomplete="off" />
+            <ComboBox v-model="type" mono :options="COMMON_TYPES" />
-            <datalist id="rule-types">
-              <option v-for="t in COMMON_TYPES" :key="t" :value="t" />
-            </datalist>
           </span>
         </label>
 
         <label v-if="!isMatch" class="row">
           <span class="k">载荷</span>
           <span class="v">
+            <ComboBox
+              v-if="isRuleSet"
+              v-model="payload"
+              mono
+              :options="providerNames"
+              placeholder="规则组名"
+            />
             <input
+              v-else
               v-model="payload"
               class="mono"
               type="text"
-              :list="isRuleSet ? 'rule-set-names' : undefined"
+              placeholder="youtube.com"
-              :placeholder="isRuleSet ? '规则组名' : 'youtube.com'"
               autocomplete="off"
               spellcheck="false"
             />
-            <datalist v-if="isRuleSet" id="rule-set-names">
-              <option v-for="name in providerNames" :key="name" :value="name" />
-            </datalist>
           </span>
         </label>
 
         <label class="row">
           <span class="k">目标</span>
           <span class="v">
-            <input
+            <ComboBox v-model="target" mono :options="outboundNames" placeholder="DIRECT" />
-              v-model="target"
-              class="mono"
-              type="text"
-              list="rule-targets"
-              placeholder="DIRECT"
-              autocomplete="off"
-            />
-            <datalist id="rule-targets">
-              <option v-for="name in outboundNames" :key="name" :value="name" />
-            </datalist>
           </span>
         </label>