/* ========================================================
   在线工具箱 · 统一设计系统 (common.css)
   方向：纸面 + 墨色 + 松绿，衬线标题，克制的层次
   所有页面（首页与工具子页）共用；配套外壳脚本 common.js
   规范说明见 docs/ui-contract.md
   ======================================================== */

/* --- Design Tokens --- */
:root {
    color-scheme: light;
    --color-primary: #18794E;
    --color-primary-light: #2A9D6A;
    --color-primary-dark: #0F5C3A;
    --color-primary-soft: rgba(24, 121, 78, 0.10);
    --color-secondary: #B4541F;
    --color-accent: #22A06B;
    --color-accent-dark: #18794E;
    --color-hot: #D9482B;
    --color-bg: #F5F3EC;
    --color-bg-card: #FFFEFA;
    --color-text: #1A1C19;
    --color-text-secondary: #4A4F47;
    --color-text-muted: #7A7F75;
    --color-border: #E0DCCF;
    --color-border-hover: #C9C4B4;
    --color-surface: #EEEBE2;
    --color-danger: #D9482B;
    --color-danger-dark: #B83A21;
    --color-warning: #C98A0B;
    --color-success: #22A06B;
    --color-info: #2F6FB0;
    --color-on-primary: #FFFFFF;
    --color-overlay: rgba(26, 28, 25, 0.45);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-full: 999px;
    --shadow-sm: 0 1px 2px rgba(40, 36, 20, 0.06);
    --shadow-md: 0 6px 18px rgba(40, 36, 20, 0.08);
    --shadow-lg: 0 18px 48px rgba(40, 36, 20, 0.16);
    --transition-fast: 150ms ease;
    --transition-normal: 220ms ease;
    --font-sans: "HarmonyOS Sans SC", "MiSans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
    --font-display: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
    --font-mono: "JetBrains Mono", "Cascadia Code", "Fira Code", "SF Mono", Consolas, Menlo, monospace;
    --bar-height: 56px;
    --page-max: 1200px;
    --page-pad: clamp(14px, 3.2vw, 32px);
    --safe-bottom: env(safe-area-inset-bottom, 0px);
}

:root[data-theme="dark"] {
    color-scheme: dark;
    --color-primary: #45C08A;
    --color-primary-light: #63D3A0;
    --color-primary-dark: #2FA873;
    --color-primary-soft: rgba(69, 192, 138, 0.14);
    --color-secondary: #E0915B;
    --color-accent: #45C08A;
    --color-accent-dark: #2FA873;
    --color-hot: #F0704F;
    --color-bg: #121411;
    --color-bg-card: #1A1D19;
    --color-text: #E9E7DF;
    --color-text-secondary: #B9BCB1;
    --color-text-muted: #878B80;
    --color-border: #2C312A;
    --color-border-hover: #3E453B;
    --color-surface: #232722;
    --color-danger: #F0704F;
    --color-danger-dark: #D9583A;
    --color-warning: #E0AE3B;
    --color-success: #45C08A;
    --color-info: #6FA8E0;
    --color-on-primary: #0C1A13;
    --color-overlay: rgba(0, 0, 0, 0.6);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 6px 18px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 18px 48px rgba(0, 0, 0, 0.55);
}

/* --- Reset & Base --- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    -webkit-text-size-adjust: 100%;
    scroll-padding-top: calc(var(--bar-height) + 16px);
}

body {
    font-family: var(--font-sans);
    font-size: 15px;
    line-height: 1.6;
    background-color: var(--color-bg);
    background-image: radial-gradient(circle at 1px 1px, rgba(120, 115, 95, 0.09) 1px, transparent 0);
    background-size: 22px 22px;
    color: var(--color-text);
    min-height: 100vh;
    min-height: 100dvh;
    overflow-wrap: anywhere;
}

[hidden] { display: none !important; }
img, canvas, video, svg { max-width: 100%; }
a { color: var(--color-primary); }
::selection { background: var(--color-primary); color: var(--color-on-primary); }

h1, h2, h3, h4 { line-height: 1.3; color: var(--color-text); }

:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

/* ========================================================
   外壳：顶栏 / 命令面板 / 页脚（由 common.js 注入）
   ======================================================== */
.tb-bar {
    position: sticky;
    top: 0;
    z-index: 200;
    height: var(--bar-height);
    background: color-mix(in srgb, var(--color-bg) 86%, transparent);
    backdrop-filter: blur(14px) saturate(1.4);
    -webkit-backdrop-filter: blur(14px) saturate(1.4);
    border-bottom: 1px solid var(--color-border);
}
.tb-bar-inner {
    max-width: calc(var(--page-max) + 2 * var(--page-pad));
    height: 100%;
    margin: 0 auto;
    padding: 0 var(--page-pad);
    display: flex;
    align-items: center;
    gap: 12px;
}
body[data-page="home"] .tb-bar-inner { max-width: 1560px; }
.tb-brand {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--color-text);
    text-decoration: none;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.1rem;
    letter-spacing: 0.02em;
    white-space: nowrap;
    flex-shrink: 0;
}
.tb-brand-mark {
    width: 30px; height: 30px;
    border-radius: 9px;
    background: var(--color-primary);
    color: var(--color-on-primary);
    display: grid; place-items: center;
    box-shadow: inset 0 -3px 0 rgba(0, 0, 0, 0.16);
}
.tb-crumb {
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 0;
    flex: 1;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}
.tb-crumb a { color: inherit; text-decoration: none; white-space: nowrap; }
.tb-crumb a:hover { color: var(--color-primary); }
.tb-crumb-sep { opacity: 0.5; }
.tb-crumb-current {
    color: var(--color-text);
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.tb-bar-spacer { flex: 1; }
.tb-actions { display: flex; align-items: center; gap: 4px; flex-shrink: 0; }
.tb-icon-btn, .tb-search-btn {
    appearance: none;
    border: 1px solid transparent;
    background: transparent;
    color: var(--color-text-secondary);
    height: 38px;
    min-width: 38px;
    border-radius: var(--radius-sm);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    cursor: pointer;
    font: inherit;
    font-size: 0.875rem;
    transition: background-color var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}
.tb-icon-btn:hover, .tb-search-btn:hover { background: var(--color-surface); color: var(--color-text); }
.tb-icon-btn[aria-pressed="true"] { color: var(--color-warning); }
.tb-icon-btn[aria-pressed="true"] svg { fill: currentColor; }
.tb-search-btn {
    padding: 0 10px 0 12px;
    border-color: var(--color-border);
    background: var(--color-bg-card);
    color: var(--color-text-muted);
}
.tb-search-btn kbd, .tb-kbd {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    padding: 1px 6px;
    border: 1px solid var(--color-border);
    border-radius: 5px;
    background: var(--color-surface);
    color: var(--color-text-muted);
}

/* 命令面板 */
.tb-palette {
    position: fixed; inset: 0; z-index: 1000;
    background: var(--color-overlay);
    display: flex; align-items: flex-start; justify-content: center;
    padding: 12vh 16px 16px;
    animation: tb-fade 140ms ease;
}
.tb-palette-panel {
    width: min(640px, 100%);
    max-height: min(560px, 76vh);
    display: flex; flex-direction: column;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    animation: tb-pop 180ms cubic-bezier(.2, .9, .3, 1.2);
}
.tb-palette-input {
    appearance: none;
    width: 100%;
    border: 0 !important;
    border-bottom: 1px solid var(--color-border) !important;
    border-radius: 0 !important;
    outline: none;
    box-shadow: none !important;
    padding: 16px 18px !important;
    font: inherit;
    font-size: 1.05rem !important;
    background: transparent !important;
    color: var(--color-text);
}
.tb-palette-list { overflow-y: auto; padding: 6px; overscroll-behavior: contain; }
.tb-palette-group { padding: 10px 12px 4px; font-size: 0.75rem; color: var(--color-text-muted); letter-spacing: 0.08em; }
.tb-palette-item {
    display: flex; align-items: center; gap: 10px;
    padding: 9px 12px;
    border-radius: var(--radius-sm);
    color: var(--color-text);
    text-decoration: none;
    cursor: pointer;
}
.tb-palette-item small { color: var(--color-text-muted); margin-left: auto; white-space: nowrap; font-size: 0.75rem; }
.tb-palette-item span { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.tb-palette-item em { font-style: normal; color: var(--color-text-muted); font-size: 0.8125rem; }
.tb-palette-item.is-active, .tb-palette-item:hover { background: var(--color-primary-soft); }
.tb-palette-empty { padding: 28px; text-align: center; color: var(--color-text-muted); }
.tb-palette-foot {
    display: flex; gap: 14px; padding: 8px 14px;
    border-top: 1px solid var(--color-border);
    font-size: 0.75rem; color: var(--color-text-muted);
}

/* 工具页标题区 */
.tb-pagehead { margin-bottom: 1.25rem; }
.tb-pagehead h1, .container > h1, .tb-main > h1 {
    font-family: var(--font-display);
    font-size: clamp(1.4rem, 1rem + 1.6vw, 1.9rem);
    font-weight: 700;
    letter-spacing: 0.01em;
    text-align: left;
    margin-bottom: 0.25rem;
}
.tb-lead { color: var(--color-text-muted); font-size: 0.9375rem; max-width: 62ch; margin-bottom: 1.25rem; }
.tb-shell .back-link { display: none !important; }

/* 页脚：相关工具 */
.tb-foot {
    max-width: calc(var(--page-max) + 2 * var(--page-pad));
    margin: 2.5rem auto 0;
    padding: 1.5rem var(--page-pad) calc(2rem + var(--safe-bottom));
    border-top: 1px dashed var(--color-border-hover);
}
.tb-foot-title { font-size: 0.8125rem; color: var(--color-text-muted); letter-spacing: 0.08em; margin-bottom: 0.75rem; }
.tb-related { display: flex; flex-wrap: wrap; gap: 8px; }
.tb-related a {
    padding: 6px 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    background: var(--color-bg-card);
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.8125rem;
    transition: border-color var(--transition-fast), color var(--transition-fast);
}
.tb-related a:hover { border-color: var(--color-primary); color: var(--color-primary); }
.tb-foot-note { margin-top: 1rem; font-size: 0.75rem; color: var(--color-text-muted); }

/* Toast */
.tb-toasts {
    position: fixed; left: 50%; bottom: calc(24px + var(--safe-bottom)); transform: translateX(-50%);
    z-index: 1100; display: flex; flex-direction: column; gap: 8px; align-items: center; pointer-events: none;
    width: max-content; max-width: calc(100vw - 32px);
}
.tb-toast {
    padding: 10px 16px;
    border-radius: var(--radius-full);
    background: var(--color-text);
    color: var(--color-bg);
    font-size: 0.875rem; font-weight: 500;
    box-shadow: var(--shadow-lg);
    animation: tb-pop 200ms cubic-bezier(.2, .9, .3, 1.2);
}
.tb-toast.is-error { background: var(--color-danger); color: #fff; }
.tb-toast.is-success { background: var(--color-primary); color: var(--color-on-primary); }

@keyframes tb-fade { from { opacity: 0; } }
@keyframes tb-pop { from { opacity: 0; transform: translateY(8px) scale(0.98); } }

/* ========================================================
   页面容器与布局
   ======================================================== */
.container, .tb-main {
    max-width: calc(var(--page-max) + 2 * var(--page-pad));
    margin: 0 auto;
    padding: 1.5rem var(--page-pad) 1rem;
}
.tb-main--narrow { max-width: calc(760px + 2 * var(--page-pad)); }
.tb-main--wide { max-width: calc(1480px + 2 * var(--page-pad)); }

.tb-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: clamp(14px, 2.4vw, 24px);
    box-shadow: var(--shadow-sm);
}
.tb-card + .tb-card { margin-top: 1rem; }
.tb-split > .tb-card, .tb-grid > .tb-card, .tb-stack > .tb-card, .tb-row > .tb-card { margin-top: 0; }
.tb-card-title { font-size: 0.9375rem; font-weight: 600; margin-bottom: 0.875rem; display: flex; align-items: center; gap: 8px; }

.tb-stack { display: flex; flex-direction: column; gap: 1rem; }
.tb-row { display: flex; flex-wrap: wrap; align-items: center; gap: 0.625rem; }
.tb-row--end { justify-content: flex-end; }
.tb-row--between { justify-content: space-between; }
.tb-grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(min(220px, 100%), 1fr)); }
.tb-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.tb-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
/* 左侧设置 + 右侧预览 的常见工作区 */
.tb-split { display: grid; gap: 1rem; grid-template-columns: minmax(280px, 360px) minmax(0, 1fr); align-items: start; }
.tb-split--even { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }

/* 表单 */
.tb-field { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
.tb-label, .tb-field > label { font-size: 0.8125rem; font-weight: 600; color: var(--color-text-secondary); }
.tb-hint { font-size: 0.8125rem; color: var(--color-text-muted); }

input[type="text"], input[type="number"], input[type="date"], input[type="time"], input[type="datetime-local"],
input[type="month"], input[type="password"], input[type="search"], input[type="url"], input[type="email"], input[type="tel"],
select, textarea, .tb-input {
    appearance: none;
    padding: 0.55rem 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 0.9375rem;
    line-height: 1.5;
    color: var(--color-text);
    background-color: var(--color-bg-card);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
    outline: none;
    max-width: 100%;
    min-height: 40px;
}
.tb-field > input, .tb-field > select, .tb-field > textarea { width: 100%; }
select {
    cursor: pointer;
    padding-right: 2rem;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%237A7F75' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.7rem center;
}
select[multiple], select[size] { background-image: none; padding-right: 0.75rem; }
input:hover, select:hover, textarea:hover { border-color: var(--color-border-hover); }
input:focus, select:focus, textarea:focus, .tb-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-soft);
}
input::placeholder, textarea::placeholder { color: var(--color-text-muted); opacity: 0.8; }
input:disabled, select:disabled, textarea:disabled, button:disabled { opacity: 0.55; cursor: not-allowed; }
input[type="checkbox"], input[type="radio"] { accent-color: var(--color-primary); width: 16px; height: 16px; }
input[type="range"] { accent-color: var(--color-primary); width: 100%; min-height: 28px; }
input[type="color"] { width: 44px; height: 40px; padding: 3px; border: 1px solid var(--color-border); border-radius: var(--radius-sm); background: var(--color-bg-card); cursor: pointer; }

textarea, pre {
    width: 100%;
    height: 400px;
    padding: 0.875rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-mono);
    font-size: 13px;
    line-height: 1.6;
    color: var(--color-text);
    resize: vertical;
}
textarea.tb-auto, pre.tb-auto { height: auto; min-height: 120px; }
pre { background-color: var(--color-surface); overflow: auto; white-space: pre-wrap; word-break: break-word; }
code { font-family: var(--font-mono); font-size: 13px; tab-size: 4; }

/* 按钮：无 class 的 <button> 保持旧页面的主按钮外观；新代码请使用 .tb-btn */
button:not([class]), .tb-btn, .btn, button.btn-success, button.btn-danger, button.btn-secondary {
    appearance: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    min-height: 40px;
    padding: 0.5rem 1rem;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 0.875rem;
    font-weight: 600;
    line-height: 1.2;
    color: var(--color-on-primary);
    background-color: var(--color-primary);
    cursor: pointer;
    text-decoration: none;
    white-space: nowrap;
    user-select: none;
    transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}
button:not([class]):hover, .tb-btn:hover, .btn:hover { background-color: var(--color-primary-dark); }
button:not([class]):active, .tb-btn:active, .btn:active { transform: translateY(1px); }

.tb-btn--ghost, .btn-secondary, button.btn-secondary, button[onclick*="clear"]:not([class]), button[onclick*="Clear"]:not([class]) {
    background-color: var(--color-bg-card);
    color: var(--color-text);
    border-color: var(--color-border);
}
.tb-btn--ghost:hover, .btn-secondary:hover, button.btn-secondary:hover, button[onclick*="clear"]:not([class]):hover, button[onclick*="Clear"]:not([class]):hover {
    background-color: var(--color-surface);
    border-color: var(--color-border-hover);
}
.tb-btn--danger, .btn-danger, button.btn-danger { background-color: var(--color-danger); color: #fff; }
.tb-btn--danger:hover, .btn-danger:hover, button.btn-danger:hover { background-color: var(--color-danger-dark); }
.btn-primary, .btn-success, button.btn-success { background-color: var(--color-primary); color: var(--color-on-primary); }
.btn-primary:hover, .btn-success:hover, button.btn-success:hover { background-color: var(--color-primary-dark); }
.tb-btn--sm, .btn-sm { min-height: 32px; padding: 0.3rem 0.7rem; font-size: 0.8125rem; }
.tb-btn--lg { min-height: 48px; padding: 0.7rem 1.5rem; font-size: 1rem; }
.tb-btn--block { width: 100%; }

/* 分段选择 / Tabs */
.tb-tabs {
    display: inline-flex;
    max-width: 100%;
    overflow-x: auto;
    padding: 3px;
    gap: 2px;
    border-radius: var(--radius-md);
    background: var(--color-surface);
    scrollbar-width: none;
}
.tb-tabs::-webkit-scrollbar { display: none; }
.tb-tab {
    appearance: none; border: 0; background: transparent; cursor: pointer;
    padding: 7px 14px; min-height: 36px;
    border-radius: 9px;
    font: inherit; font-size: 0.875rem; font-weight: 500;
    color: var(--color-text-secondary);
    white-space: nowrap;
    transition: background-color var(--transition-fast), color var(--transition-fast);
}
.tb-tab:hover { color: var(--color-text); }
.tb-tab.is-active, .tb-tab[aria-selected="true"] { background: var(--color-bg-card); color: var(--color-primary); box-shadow: var(--shadow-sm); font-weight: 600; }

/* 标签、徽标、提示 */
.tb-chip {
    display: inline-flex; align-items: center; gap: 4px;
    padding: 3px 10px; border-radius: var(--radius-full);
    background: var(--color-surface); color: var(--color-text-secondary);
    font-size: 0.75rem; font-weight: 500;
    border: 1px solid transparent;
}
button.tb-chip { appearance: none; cursor: pointer; font-family: inherit; min-height: 30px; }
button.tb-chip:hover { border-color: var(--color-border-hover); }
.tb-chip.is-active { background: var(--color-primary-soft); color: var(--color-primary); border-color: var(--color-primary); }
.tb-alert {
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    border-left: 3px solid var(--color-info);
    background: var(--color-bg-card);
    color: var(--color-text-secondary);
    font-size: 0.875rem;
}
.tb-alert--warn { border-left-color: var(--color-warning); }
.tb-alert--error { border-left-color: var(--color-danger); color: var(--color-danger); }
.tb-alert--ok { border-left-color: var(--color-success); }

/* 结果与数据展示 */
.result, .tb-output {
    padding: 1rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    word-break: break-all;
    white-space: pre-wrap;
}
.tb-stats { display: grid; gap: 0.75rem; grid-template-columns: repeat(auto-fit, minmax(min(140px, 100%), 1fr)); }
.tb-stat { padding: 0.875rem 1rem; border-radius: var(--radius-md); background: var(--color-surface); }
.tb-stat-label { font-size: 0.75rem; color: var(--color-text-muted); }
.tb-stat-value { font-family: var(--font-display); font-size: 1.5rem; font-weight: 700; color: var(--color-primary); line-height: 1.25; font-variant-numeric: tabular-nums; }

.tb-table-wrap { overflow-x: auto; border: 1px solid var(--color-border); border-radius: var(--radius-md); }
table.tb-table { width: 100%; border-collapse: collapse; font-size: 0.875rem; background: var(--color-bg-card); }
.tb-table th, .tb-table td { padding: 0.6rem 0.75rem; text-align: left; border-bottom: 1px solid var(--color-border); }
.tb-table th { background: var(--color-surface); font-weight: 600; color: var(--color-text-secondary); white-space: nowrap; }
.tb-table tr:last-child td { border-bottom: 0; }

/* 文件拖放区 */
.tb-drop {
    display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 6px;
    min-height: 160px; padding: 1.5rem; text-align: center;
    border: 2px dashed var(--color-border-hover);
    border-radius: var(--radius-lg);
    background: var(--color-bg-card);
    color: var(--color-text-muted);
    cursor: pointer;
    transition: border-color var(--transition-fast), background-color var(--transition-fast);
}
.tb-drop:hover, .tb-drop.is-over { border-color: var(--color-primary); background: var(--color-primary-soft); color: var(--color-primary); }
.tb-drop input[type="file"] { display: none; }
.tb-drop strong { color: var(--color-text); font-size: 0.9375rem; }

.tb-empty { padding: 2.5rem 1rem; text-align: center; color: var(--color-text-muted); }
.print-only { display: none; }
.tb-mono { font-family: var(--font-mono); }
.tb-muted { color: var(--color-text-muted); }
.tb-sr { position: absolute; width: 1px; height: 1px; min-height: 0; padding: 0; border: 0; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ========================================================
   旧版结构兼容（format-container 双栏、notification 等）
   ======================================================== */
.format-container {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
    gap: 1.25rem;
    background: var(--color-bg-card);
    padding: clamp(14px, 2.4vw, 24px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}
.input-section, .output-section { display: flex; flex-direction: column; gap: 0.625rem; min-width: 0; }
.input-section h2, .output-section h2 { font-size: 0.8125rem; font-weight: 600; color: var(--color-text-secondary); letter-spacing: 0.06em; }
.button-group { display: flex; flex-direction: column; gap: 0.5rem; justify-content: center; }

.file-input { position: relative; }
.file-input input[type="file"] { position: absolute; opacity: 0; width: 0; height: 0; }
.file-input label {
    display: inline-flex; align-items: center; justify-content: center; gap: 0.375rem;
    min-height: 40px; width: 100%;
    padding: 0.5rem 1rem;
    background-color: var(--color-bg-card);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 0.875rem; font-weight: 600;
    cursor: pointer;
}
.file-input label:hover { background-color: var(--color-surface); }

.options { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; padding: 0.75rem 0; }
.options label { display: flex; align-items: center; gap: 0.375rem; font-size: 0.875rem; color: var(--color-text-secondary); cursor: pointer; }
.options input[type="number"] { width: 80px; }

.sub-section { margin-top: 1.25rem; }
.sub-section h3 { font-size: 0.8125rem; font-weight: 600; color: var(--color-text-muted); letter-spacing: 0.06em; margin-bottom: 0.75rem; }

.notification {
    position: fixed;
    left: 50%; bottom: calc(24px + var(--safe-bottom));
    transform: translate(-50%, 8px);
    padding: 10px 16px;
    background: var(--color-text);
    color: var(--color-bg);
    border-radius: var(--radius-full);
    font-size: 0.875rem; font-weight: 500;
    opacity: 0;
    transition: opacity var(--transition-normal), transform var(--transition-normal);
    z-index: 1100;
    pointer-events: none;
    box-shadow: var(--shadow-lg);
}
.notification.show { opacity: 1; transform: translate(-50%, 0); }

/* --- Accessibility --- */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ========================================================
   响应式：≤1024 平板 / ≤768 竖屏平板与大屏手机 / ≤480 手机
   ======================================================== */
@media (max-width: 1024px) {
    .tb-split { grid-template-columns: minmax(240px, 320px) minmax(0, 1fr); }
    .tb-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 768px) {
    :root { --bar-height: 52px; }
    .tb-split, .tb-split--even, .format-container { grid-template-columns: minmax(0, 1fr); }
    .tb-grid--3, .tb-grid--2 { grid-template-columns: minmax(0, 1fr); }
    .button-group { flex-direction: row; flex-wrap: wrap; }
    .button-group > * { flex: 1 1 auto; }
    textarea, pre { height: 240px; }
    .tb-search-btn span, .tb-search-btn kbd, .tb-crumb-cat, .tb-crumb-cat + .tb-crumb-sep { display: none; }
    .tb-search-btn { border-color: transparent; background: transparent; padding: 0; color: var(--color-text-secondary); }
    .tb-brand-text { display: none; }
    .tb-palette { padding: 0; align-items: stretch; }
    .tb-palette-panel { width: 100%; max-height: none; height: 100%; border-radius: 0; border: 0; }
    .tb-palette-foot { display: none; }
    /* 防止 iOS 聚焦时页面缩放 */
    input[type="text"], input[type="number"], input[type="date"], input[type="time"], input[type="datetime-local"],
    input[type="month"], input[type="password"], input[type="search"], input[type="url"], input[type="email"], input[type="tel"],
    select, textarea { font-size: 16px; }
    textarea { font-size: 14px; }
}

@media (max-width: 480px) {
    .container, .tb-main { padding-top: 1rem; }
    .tb-card, .format-container { border-radius: var(--radius-md); }
    .tb-stat-value { font-size: 1.25rem; }
}

@media print {
    /* 打印始终用浅色令牌，避免深色模式下打出深底浅字 */
    :root[data-theme="dark"] {
        color-scheme: light;
        --color-primary: #18794E; --color-primary-light: #2A9D6A; --color-primary-dark: #0F5C3A; --color-primary-soft: rgba(24, 121, 78, 0.10);
        --color-bg: #FFFFFF; --color-bg-card: #FFFFFF; --color-surface: #F2F2F2;
        --color-text: #000000; --color-text-secondary: #333333; --color-text-muted: #666666;
        --color-border: #CCCCCC; --color-border-hover: #999999; --color-on-primary: #FFFFFF;
        --color-danger: #D9482B; --color-warning: #C98A0B; --color-success: #22A06B; --color-info: #2F6FB0;
    }
    .print-only { display: block !important; }
    .tb-bar, .tb-foot, .tb-toasts, .tb-palette, .tb-lead, .no-print { display: none !important; }
    body { background: #fff; color: #000; }
    .container, .tb-main { max-width: none; padding: 0; }
}