/* EchoFlow shared design system: warm paper, one brand orange, quiet motion. */
:root{color-scheme:light dark;
  --bg:oklch(98.4% .006 75);--card:oklch(100% 0 0);--surface:oklch(95.6% .008 75);--hover:oklch(93% .01 70);
  --ink:oklch(23% .012 60);--muted:oklch(50% .013 60);--faint:oklch(66% .012 65);--line:oklch(90% .008 70);
  --brand:#ff5a1f;--accent:oklch(54% .19 38);--accent-soft:oklch(94.5% .035 50);--accent-line:oklch(84% .08 45);
  --selected:oklch(100% 0 0);--focus:oklch(60% .2 38);--good:oklch(52% .12 150);--bad:oklch(54% .19 25);
  --shadow-sm:0 1px 2px oklch(30% .02 60/.06),0 0 0 .5px oklch(30% .02 60/.08);
  --shadow-md:0 1px 2px oklch(30% .02 60/.05),0 8px 24px -10px oklch(30% .03 50/.22),0 0 0 .5px oklch(30% .02 60/.07);
  --radius:12px;--radius-lg:16px;
  --ease:cubic-bezier(.22,1,.36,1);--spring:cubic-bezier(.34,1.45,.64,1);
  --t-fast:140ms;--t-med:240ms;--t-slow:420ms}
@media(prefers-color-scheme:dark){:root{
  --bg:oklch(19% .008 65);--card:oklch(23.5% .009 65);--surface:oklch(26% .009 65);--hover:oklch(30% .01 65);
  --ink:oklch(95% .008 75);--muted:oklch(73% .012 65);--faint:oklch(58% .012 65);--line:oklch(32% .01 65);
  --accent:oklch(76% .15 48);--accent-soft:oklch(32% .06 45);--accent-line:oklch(48% .1 45);
  --selected:oklch(36% .012 65);--focus:oklch(76% .15 45);--good:oklch(78% .12 150);--bad:oklch(76% .14 25);
  --shadow-sm:0 0 0 .5px oklch(100% 0 0/.08);--shadow-md:0 0 0 .5px oklch(100% 0 0/.09),0 10px 30px -12px oklch(0% 0 0/.6)}}

*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font:13px/1.55 -apple-system,BlinkMacSystemFont,"PingFang SC","Segoe UI","Microsoft YaHei",sans-serif;-webkit-font-smoothing:antialiased}
button,input,select{font:inherit;color:inherit}
button,a,input,select,summary,label{-webkit-tap-highlight-color:transparent}
button{cursor:pointer;border:0;background:none}
button:disabled,select:disabled,input:disabled{opacity:.45;cursor:default}
:focus-visible{outline:2px solid var(--focus);outline-offset:2px;border-radius:6px}
a{color:var(--accent);text-underline-offset:3px}
h1,h2,h3,p{margin:0}
h1{font-size:18px;line-height:1.3;font-weight:650;letter-spacing:-.02em}
h2{font-size:21px;line-height:1.4;letter-spacing:-.02em}
h3{font-size:14px;font-weight:600}
small,.muted,.hint{color:var(--muted);font-size:12px}
.hint{line-height:1.6}
.section-label{font-size:12px;color:var(--muted);font-weight:500;margin-bottom:8px}
.brand{display:flex;gap:9px;align-items:center}
.brand img{width:26px;height:26px}
.brand strong{font-size:16px;font-weight:650;letter-spacing:-.03em}

/* Buttons */
.text-button{display:inline-flex;align-items:center;gap:5px;color:var(--muted);padding:5px 9px;border-radius:8px;min-height:30px;transition:background var(--t-fast) var(--ease),color var(--t-fast) var(--ease)}
.text-button:hover{background:var(--hover);color:var(--ink)}
.text-button:active{transform:scale(.97)}
.text-button.accent{color:var(--accent)}
.icon-button{display:inline-grid;place-items:center;width:32px;height:32px;border-radius:9px;color:var(--muted);transition:background var(--t-fast) var(--ease),color var(--t-fast) var(--ease),transform var(--t-fast) var(--ease)}
.icon-button:hover{background:var(--hover);color:var(--ink)}
.icon-button:active{transform:scale(.92)}
.icon-button svg{width:17px;height:17px}
.button{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:8px 14px;min-height:36px;border-radius:10px;background:var(--card);box-shadow:var(--shadow-sm);transition:background var(--t-fast) var(--ease),transform var(--t-fast) var(--ease),box-shadow var(--t-fast) var(--ease)}
.button:hover{background:var(--hover)}
.button:active{transform:scale(.97)}
.button.primary{color:#fff;background:var(--brand);box-shadow:0 1px 2px oklch(50% .2 38/.3),0 6px 16px -8px oklch(60% .2 38/.7)}
.button.primary:hover{background:oklch(64% .21 38)}
.visually-hidden{position:absolute!important;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* Segmented control with a sliding thumb. The group sets --count and --active. */
.segmented{position:relative;display:grid;grid-template-columns:repeat(var(--count,3),minmax(0,1fr));background:var(--surface);padding:3px;border-radius:11px;isolation:isolate}
.segmented::before{content:"";position:absolute;z-index:-1;top:3px;bottom:3px;left:3px;width:calc((100% - 6px)/var(--count,3));border-radius:8px;background:var(--selected);box-shadow:var(--shadow-sm);transform:translateX(calc(var(--active,0)*100%));transition:transform var(--t-slow) var(--spring),opacity var(--t-fast)}
.segmented[data-active="-1"]::before{opacity:0}
.segmented button,.segmented label{position:relative;display:flex;align-items:center;justify-content:center;min-height:34px;padding:5px;border-radius:8px;white-space:nowrap;color:var(--muted);cursor:pointer;transition:color var(--t-med) var(--ease)}
.segmented button:hover,.segmented label:hover{color:var(--ink)}
.segmented button[aria-pressed=true],.segmented button[aria-checked=true],.segmented label:has(input:checked){color:var(--ink);font-weight:600}
.segmented input{position:absolute;opacity:0;width:1px;height:1px}
.segmented label:has(input:focus-visible){outline:2px solid var(--focus);outline-offset:1px}

/* Tabs: a pill track with a sliding indicator. */
.tabs{position:relative;display:grid;grid-template-columns:1fr 1fr;padding:3px;border-radius:11px;background:var(--surface);isolation:isolate}
.tabs::before{content:"";position:absolute;z-index:-1;top:3px;bottom:3px;left:3px;width:calc(50% - 3px);border-radius:8px;background:var(--selected);box-shadow:var(--shadow-sm);transform:translateX(calc(var(--active,0)*100%));transition:transform var(--t-slow) var(--spring)}
.tabs[data-active=subtitles]{--active:1}
.tabs button{position:relative;min-height:30px;color:var(--muted);font-weight:500;transition:color var(--t-med) var(--ease)}
.tabs button[aria-selected=true]{color:var(--ink);font-weight:600}
.tabs button[data-available=true]::after{content:"";display:inline-block;vertical-align:2px;margin-left:5px;width:6px;height:6px;border-radius:50%;background:var(--brand);animation:pop var(--t-slow) var(--spring) both}

/* Rows and form controls */
.row{min-height:44px;display:flex;align-items:center;justify-content:space-between;gap:16px}
.row>span:first-child{min-width:0}
.row .description{display:block;color:var(--muted);font-size:12px;margin-top:2px}
.row select,select.field{appearance:none;-webkit-appearance:none;min-height:32px;max-width:185px;padding:5px 28px 5px 11px;border:0;border-radius:9px;background:var(--surface) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M1 1l4 4 4-4' fill='none' stroke='%23999' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") no-repeat right 11px center;cursor:pointer;transition:background-color var(--t-fast) var(--ease)}
.row select:hover,select.field:hover{background-color:var(--hover)}
input[type=checkbox][role=switch]{appearance:none;-webkit-appearance:none;flex-shrink:0;width:38px;height:23px;margin:0;border-radius:23px;background:var(--hover);position:relative;cursor:pointer;transition:background var(--t-med) var(--ease)}
input[type=checkbox][role=switch]::before{content:"";position:absolute;top:2px;left:2px;width:19px;height:19px;border-radius:19px;background:#fff;box-shadow:0 1px 3px oklch(0% 0 0/.22),0 0 0 .5px oklch(0% 0 0/.04);transition:transform var(--t-slow) var(--spring),width var(--t-fast) var(--ease)}
input[type=checkbox][role=switch]:active::before{width:23px}
input[type=checkbox][role=switch]:checked{background:var(--brand)}
input[type=checkbox][role=switch]:checked::before{transform:translateX(15px)}
input[type=checkbox][role=switch]:checked:active::before{transform:translateX(11px)}
.separator{height:1px;background:var(--line);margin:14px 0}

/* Status with a live dot */
.status-line{position:relative;padding-left:16px}
.status-line::before{content:"";position:absolute;left:1px;top:6px;width:8px;height:8px;border-radius:50%;background:var(--faint);transition:background var(--t-med) var(--ease)}
.status-line[data-tone=ready]::before{background:var(--good)}
.status-line[data-tone=busy]::before{background:var(--brand);animation:breathe 1.4s var(--ease) infinite}
.status-line[data-tone=error]::before{background:var(--bad)}
.status-line[data-tone=warning]::before{background:oklch(75% .16 70)}
.status-line .hint{margin-top:1px}

/* Progressive disclosure: a summary row that reveals its region smoothly. */
.disclosure{border-radius:var(--radius);background:var(--card);box-shadow:var(--shadow-sm)}
.disclosure+.disclosure{margin-top:8px}
.disclosure-toggle{display:flex;width:100%;align-items:center;gap:10px;min-height:46px;padding:8px 12px;border-radius:var(--radius);text-align:left;transition:background var(--t-fast) var(--ease)}
.disclosure-toggle:hover{background:color-mix(in oklab,var(--hover) 55%,transparent)}
.disclosure-toggle .disclosure-title{font-weight:550;white-space:nowrap}
.disclosure-toggle .disclosure-summary{flex:1;min-width:0;text-align:right;color:var(--muted);font-size:12px;overflow:hidden;white-space:nowrap;text-overflow:ellipsis}
.disclosure-toggle .chevron{flex:none;width:14px;height:14px;color:var(--faint);transition:transform var(--t-med) var(--ease)}
.disclosure[data-open=true] .chevron{transform:rotate(90deg)}
.disclosure-region{display:grid;grid-template-rows:0fr;transition:grid-template-rows var(--t-med) var(--ease)}
.disclosure[data-open=true] .disclosure-region{grid-template-rows:1fr}
.disclosure-inner{min-height:0;overflow:hidden;padding:0 12px;opacity:0;transform:translateY(-4px);visibility:hidden;transition:opacity var(--t-fast) var(--ease),transform var(--t-med) var(--ease),padding var(--t-med) var(--ease),visibility 0s linear var(--t-med)}
.disclosure[data-open=true] .disclosure-inner{padding-bottom:12px;opacity:1;transform:none;visibility:visible;transition-delay:40ms,40ms,0s,0s}

/* Previews */
.reading-preview{padding:11px 12px;border-radius:10px;background:var(--surface);overflow-wrap:anywhere;--preview-size:18px}
.preview-label{font-size:11px;color:var(--muted);margin-bottom:5px}
.reading-preview .preview-source{font-size:12px;color:var(--muted);line-height:1.55}
.reading-preview .preview-translation{font-size:var(--preview-size);line-height:1.6;margin-top:3px;transition:font-size var(--t-med) var(--ease)}
.reading-preview[data-mode=chinese] .preview-source,.reading-preview[data-mode=original] .preview-translation{display:none}
.reading-preview[data-mode=original] .preview-source{font-size:var(--preview-size);color:var(--ink)}
.reading-preview .chunk-one,.reading-preview .chunk-two{border-radius:3px;transition:background-color var(--t-med) var(--ease)}
.reading-preview[data-chunks=true] .chunk-one{background:oklch(70% .14 55/.24)}
.reading-preview[data-chunks=true] .chunk-two{background:oklch(70% .1 225/.24)}
.subtitle-preview{display:grid;grid-template-areas:"label" "zh" "original" "peek";gap:4px;padding:16px 12px 14px;border-radius:10px;text-align:center;min-height:112px;--preview-scale:1;color:#fff;background:radial-gradient(120% 90% at 50% 0%,oklch(38% .03 250),oklch(18% .02 250));text-shadow:0 1px 3px oklch(0% 0 0/.8)}
.subtitle-preview .preview-label{grid-area:label;color:oklch(100% 0 0/.55);text-shadow:none}
.subtitle-preview .preview-zh{grid-area:zh;font-size:calc(18px * var(--preview-scale));font-weight:600;line-height:1.4;transition:opacity var(--t-med) var(--ease),filter var(--t-med) var(--ease),transform var(--t-med) var(--ease)}
.subtitle-preview .preview-original{grid-area:original;font-size:calc(13px * var(--preview-scale));color:oklch(100% 0 0/.8)}
.subtitle-preview[data-mode=scaffold]{grid-template-areas:"label" "original" "zh" "peek"}
.subtitle-preview[data-mode=scaffold] .preview-original{font-size:calc(17px * var(--preview-scale));color:#fff}
.subtitle-preview[data-mode=scaffold] .preview-zh{font-size:calc(14px * var(--preview-scale));font-weight:400}
.subtitle-preview[data-mode=scaffold]:not([data-peek=true]) .preview-zh{opacity:0;filter:blur(5px);transform:translateY(3px)}
.subtitle-preview[data-mode=off] .preview-zh{display:none}
.subtitle-preview[data-mode=pure] .chunk-one{color:#ffc48f}.subtitle-preview[data-mode=pure] .chunk-two{color:#a6dcff}
.peek-button{grid-area:peek;justify-self:center;margin-top:6px;font-size:12px;color:#fff;padding:4px 12px;border-radius:999px;background:oklch(100% 0 0/.14);text-shadow:none;transition:background var(--t-fast) var(--ease),transform var(--t-fast) var(--ease)}
.peek-button:active{transform:scale(.95);background:oklch(100% 0 0/.24)}
.subtitle-preview:not([data-mode=scaffold]) .peek-button{display:none}

details>summary{cursor:pointer;color:var(--muted);font-size:12px;padding:6px 0}
details[open]>summary{margin-bottom:5px}
.prompt{white-space:pre-wrap;font:12px/1.7 -apple-system,"PingFang SC",sans-serif;color:var(--muted);max-height:260px;overflow:auto;margin:0}
.save-message{font-size:12px;min-height:18px;color:var(--good);transition:opacity var(--t-med) var(--ease)}
.save-message:empty{opacity:0}
.save-message[data-error=true]{color:var(--bad)}
[hidden]{display:none!important}

@keyframes pop{from{transform:scale(0)}to{transform:scale(1)}}
@keyframes breathe{0%,100%{box-shadow:0 0 0 0 oklch(66% .21 38/.45)}50%{box-shadow:0 0 0 4px oklch(66% .21 38/0)}}
@keyframes rise{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{transition-duration:.01ms!important;transition-delay:0s!important;animation:none!important}}