Settings-backed conversation content font size
Settings 支撑的会话正文字号
The conversation's body text size was fixed (14px after the 0.875 markdown-ladder rescale). Users asked for a Settings control: a "字号大小" row under General → Appearance with a stepper, range 12–17, default 14, that resizes the transcript body text and the composer input text together.
English
Problem
The conversation's body text size was fixed (14px after the 0.875 markdown-ladder rescale). Users asked for a Settings control: a "字号大小" row under General → Appearance with a stepper, range 12–17, default 14, that resizes the transcript body text and the composer input text together.
Decision
The theme plugin owns the setting. ThemeSettingsSchema gains fontSize (z.number().step(1).min(12).max(17).default(14)) beside preference in the existing ui-theme namespace — one durable section, one settings scope, one adoption path. ThemeRuntime carries fontSize in ThemeSnapshot, exposes setFontSize(px) (integer-and-range validated, throws a teaching error), and republishes on theme/change. The same plugin registers the FontSizeRow into settings.general.item at order 11, directly under the Appearance cubes (order 10).
Presentation rides the existing snapshot pipeline. The service never touches the DOM: ui-layout's ThemePresenter writes --dsh-content-font-size on body from each snapshot (and retracts it on dispose), and the Host boot script embeds the durable value in the index response so first paint uses the chosen size — the same pre-plugin path the dark-mode attribute takes, avoiding a font-size flash.
One CSS delta variable moves the ladder, plus a derived secondary tier. gradient-shadow-text.css derives --dsh-content-font-delta: calc(var(--dsh-content-font-size, 14px) - 14px) and shifts the markdown h1–h4 and base variants (size and line height) by that same px increment, preserving the heading hierarchy and each variant's leading. Secondary-tier text — one step under the body — reads --dsh-content-font-size-secondary: min(setting − 1px, max(13px, setting − 2px)): setting −1 at ≤14, setting −2 above (12→11, 13→12, 14→13, 15→13, 16→14, 17→15), with --dsh-content-font-delta-secondary (secondary − 13px) moving its line heights. The secondary tier covers the markdown table variants, the shared DisclosureRow title (tool calls, think, commands), ToolRow/bash-row summaries and file links, think text, compaction/context/retry/error rows, StatsLine, the chat hint and open-error strips, the workflow-run panel headers/counts/statuses, the turn-status clock, reference summaries, and the note-trigger label. Small and code variants stay fixed — as does the interrupted-turn .stopped tag (11px): they are dense secondary text whose defaults would fall below legibility when stepped down. Consumers outside the token ladder at the body size read var(--dsh-content-font-size, 14px) and calc(<default line-height> + var(--dsh-content-font-delta, 0px)) directly: the assistant narration root, the user bubble (inline reference glyphs included), the composer card (whose textarea/mirror/backdrop stack inherits font metrics from the card by design), the compaction/DisclosureRow geometry (row height, leading box, expanded bodies' 22px + delta indent), the message clock and icon actions (slot-injected message-feedback actions match through the same variables), and the turn status line. Flow icons scale through each leading box's CSS edge (svg width/height overriding the glyph attributes); StateDot is exempt via its data-state attribute — a status mark, not text furniture. The fallbacks (14px body, 13px secondary) keep every surface pixel-identical when the variables are absent (tests, storybook-like mounts, remote compositions before adoption).
The stepper is a pill, not a menu. The row reuses the selector-pill geometry (h36 r18 module fill) with the value centered in the pill, the up/down arrow column revealed on hover/focus-within and absolutely anchored to the pill's right edge (so revealing never moves the value), and a px unit label after the pill. A tertiary description line under the title states the scope — the size only affects conversation content, not the application chrome. Arrows disable at the bounds; the display follows the store mirror, never the click echo — the same store/face pattern as the Appearance row.
Alternatives considered
A separate settings namespace or plugin. Rejected: the font size is an appearance preference with the same persistence, adoption, and remote-browser semantics as the theme preference; a second namespace duplicates the scope machinery for one integer.
Scaling via a multiplier (em/percentage) instead of a px delta. Rejected: multiplying spreads the 12–17px range disproportionately across the ladder (21px h1 would swing ~18–25.5px) and produces fractional line heights; the fixed px shift keeps every step integer and the hierarchy's px gaps intact.
Scaling every font token (small, code). Rejected: those variants are dense by design; at −2 the small ladder would hit 10px and code 9px, below legibility. The table variants instead join the secondary tier, bottoming out at 11px at the 12px setting — the same size think text reaches there.
Consequences
The 0.875 markdown-ladder rescale (body 16 → 14) ships with this change as the new default rendering; at the default setting the body-size consumers match that rescaled baseline, and the secondary tier renders at 13px (one step down — a deliberate demotion of the flow-row titles and summaries that previously sat at the body size). Surfaces without the variables fall back to the same defaults. A changed size persists in $DSH_HOME/settings.yaml, survives reloads without flashing (the boot script writes the durable value pre-hydration and ThemeRuntime seeds its initial snapshot from it), applies live across transcript and composer, and remote browsers keep the process-local-selection rule the theme preference already has. setFontSize joins the model-visible cordis client API catalog beside setTheme.
中文
问题
会话正文字号是固定的（markdown 阶梯按 0.875 重缩放后为 14px）。用户需要一个设置项：在 General → Appearance 下加一行「字号大小」，用步进器交互，范围 12–17，默认 14，同时调整转录正文与 composer 输入框的文字大小。
决策
主题插件拥有该设置。ThemeSettingsSchema 在既有 ui-theme namespace 的 preference 旁新增 fontSize（z.number().step(1).min(12).max(17).default(14)）——一个持久化 section、一个 settings scope、一条采纳路径。ThemeRuntime 在 ThemeSnapshot 中携带 fontSize，暴露 setFontSize(px)（校验整数与范围，越界抛教学式错误），并通过 theme/change 重新发布。同一插件把 FontSizeRow 注册进 settings.general.item，order 11，紧挨外观方块（order 10）之下。
**呈现走既有快照管线。**服务绝不接触 DOM：ui-layout 的 ThemePresenter 依据每份快照在 body 上写 --dsh-content-font-size（dispose 时收回），Host 引导脚本把持久化值嵌入 index 响应，让首帧就使用所选字号——与暗色属性同一条插件前路径，避免字号闪变。
一个 CSS 增量变量平移阶梯，另派生一个低一档层级。gradient-shadow-text.css 派生 --dsh-content-font-delta: calc(var(--dsh-content-font-size, 14px) - 14px)，把 markdown h1–h4 与 base 各变体（字号与行高）按同一像素增量平移，保持标题层级与各变体的行距。低一档文本——比正文低一档——读 --dsh-content-font-size-secondary: min(设置值 − 1px, max(13px, 设置值 − 2px))：设置 ≤14 时为设置值 −1，>14 时为设置值 −2（12→11、13→12、14→13、15→13、16→14、17→15），其行高经 --dsh-content-font-delta-secondary（低一档值 − 13px）随动。低一档覆盖：markdown 表格变体、共享 DisclosureRow 标题（工具调用、think、命令）、ToolRow/bash 行的 summary 与文件链接、think 正文、compaction/context/retry/错误行、StatsLine、chat 提示与打开失败条、workflow-run 面板的头部/计数/状态、回合状态时钟、引用摘要与笔记触发标签。small 与 code 变体保持固定——中断回合的 .stopped 标签（11px）同样固定：它们是密集次级文本，其默认值在字号下调时会低于可读下限。token 阶梯之外按正文档读取的消费方直接使用 var(--dsh-content-font-size, 14px) 与 calc(<默认行高> + var(--dsh-content-font-delta, 0px))：助手正文根节点、用户气泡（含行内引用字形）、composer 卡片（其 textarea/mirror/backdrop 三层按设计从卡片继承字体度量）、compaction/DisclosureRow 的行几何（行高、leading 盒、展开内容的 22px + delta 缩进）、消息时钟与图标操作（slot 注入的消息反馈操作经同一对变量同步缩放），以及回合状态行。流内图标经由各 leading 盒的 CSS 边长缩放（svg width/height 覆盖字形自身属性）；StateDot 通过其 data-state 属性豁免——它是状态标记，不是文字组件。回退值（正文 14px、低一档 13px）让变量缺席时（测试、独立挂载、采纳前的远程组合）所有表面逐像素不变。
**步进器是药丸控件，不是菜单。**该行复用选择器药丸几何（h36 r18 模块填充），数值在药丸内居中，上下箭头列在 hover/focus-within 时显示并绝对定位在药丸右缘（显示时数值不移动），药丸后带 px 单位标签。标题下方的三级说明行标明作用范围——字号仅影响会话内容，不影响应用外框。到达边界时对应箭头禁用；显示跟随 store 镜像，绝不跟随点击回声——与外观行相同的 store/face 模式。
已考虑的替代方案
**独立 settings namespace 或独立插件。**否决：字号与主题偏好具有相同的持久化、采纳与远程浏览器语义，属外观偏好；为一个整数复制一套 scope 机制不值得。
**用倍率（em／百分比）而非像素增量缩放。**否决：乘法会让 12–17px 的范围在阶梯上不成比例地放大（21px 的 h1 会摆动到约 18–25.5px），并产生小数行高；固定像素平移让每一档都是整数，层级间的像素差保持不变。
**缩放全部字体 token（code、small）。**否决：这些变体按设计就是密集文本；−2 档时 small 阶梯会降到 10px、code 降到 9px，低于可读下限。表格变体改为并入低一档层级，在 12px 设置下触底 11px——与 think 文本在该设置下相同。
后果
0.875 的 markdown 阶梯重缩放（正文 16 → 14）作为新的默认渲染随本变更一同交付；默认设置下正文档消费方与该重缩放基线一致，低一档渲染为 13px（低一步——这是对此前按正文档渲染的流内行标题与摘要的有意降档）。无变量的表面回退到同样的默认值。修改后的字号持久化在 $DSH_HOME/settings.yaml，重载不闪变（引导脚本在 hydration 前写入持久化值，ThemeRuntime 以它为初始快照种子），在转录与 composer 上实时生效；远程浏览器沿用主题偏好既有的进程内选择规则。setFontSize 与 setTheme 一同进入模型可见的 cordis 客户端 API 目录。