:root {
  /* Windows 计算器的分区工具台：中性工作面、蓝色主操作、固定表头与设备核对列。
     Michael Design 数据表密度 44/36px；沿用现有 win 语义色及 Segoe UI。 */
  --win-bg: #f3f3f3; --win-panel: #e6e6e6; --win-blue: #0078d7;
  --win-blue-hover: #0063b1; --win-text: #202020; --win-text-muted: #555555;
  --win-btn-bg: #ffffff; --win-btn-hover: #e5e5e5; --win-btn-active: #cccccc;
  --win-input-border: #8a8a8a; --win-border: #dedede; --win-accent-soft: #edf5fc;
  --win-critical: #a4262c; --win-critical-soft: #fdf0f0;
  --win-success: #24613b; --win-success-soft: #eef6f0;
  --win-warning: #805b12; --win-warning-soft: #fbf5e9;
  --shadow-rgb: 32 40 48; --white-rgb: 255 255 255;
  --shadow-panel: 0 1px 2px rgb(var(--shadow-rgb) / .04), 0 6px 18px rgb(var(--shadow-rgb) / .025);
  --shadow-dialog: 0 4px 10px rgb(var(--shadow-rgb) / .14), 0 24px 64px rgb(var(--shadow-rgb) / .18);
  --font-sans: "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  --font-mono: Consolas, "Cascadia Mono", monospace;
  --radius: 6px; --duration: 140ms;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; font: 14px/1.5 var(--font-sans); color: var(--win-text); background: linear-gradient(180deg, var(--win-accent-soft) -240px, var(--win-bg) 280px) fixed; }
button, input, select, textarea { font: inherit; color: inherit; }
button { min-height: 36px; padding: 6px 14px; border: 1px solid var(--win-border); border-radius: var(--radius); background: var(--win-btn-bg); box-shadow: inset 0 1px 0 rgb(var(--white-rgb) / .7); cursor: pointer; transition: background var(--duration), border-color var(--duration); white-space: nowrap; }
button:hover { background: var(--win-btn-hover); border-color: var(--win-input-border); }
button:active { background: var(--win-btn-active); }
button:disabled { opacity: .55; cursor: not-allowed; }
button.primary { color: var(--win-btn-bg); border-color: var(--win-blue); background: linear-gradient(180deg, color-mix(in srgb, var(--win-blue) 93%, var(--win-btn-bg)), var(--win-blue)); }
button.primary:hover { background: var(--win-blue-hover); border-color: var(--win-blue-hover); }
button.primary:active { background: var(--win-blue); }
button.danger { color: var(--win-critical); }
:focus-visible { outline: 2px solid var(--win-blue); outline-offset: 3px; }
input, select, textarea { width: 100%; min-height: 36px; padding: 6px 10px; background: var(--win-btn-bg); border: 1px solid var(--win-input-border); border-radius: 4px; }
input:focus, select:focus, textarea:focus { border-color: var(--win-blue); }
input::placeholder { color: var(--win-text-muted); opacity: .8; }
label { display: block; font-weight: 600; margin-bottom: 6px; }
h1, h2, h3, p { margin: 0; }
h1 { font-size: 24px; line-height: 1.4; font-weight: 600; }
h2 { font-size: 17px; font-weight: 600; }
h3 { font-size: 14px; font-weight: 600; }
p + p { margin-top: 8px; }
.muted { color: var(--win-text-muted); }
.small, .field-hint { font-size: 12px; }
.field-hint { color: var(--win-text-muted); display: block; margin-top: 5px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.skip-link { position: fixed; top: -100px; left: 16px; z-index: 10; background: var(--win-btn-bg); padding: 12px; color: var(--win-blue); }
.skip-link:focus { top: 8px; }
.app-header { border-bottom: 1px solid var(--win-border); background: color-mix(in srgb, var(--win-bg) 88%, transparent); backdrop-filter: blur(16px); }
.header-inner { max-width: 1456px; min-height: 60px; padding: 8px 28px; margin: auto; display: flex; align-items: center; gap: 12px; font-weight: 600; }
.header-inner > button { margin-left: auto; font-weight: 400; }
.app-mark { color: var(--win-blue); font-size: 25px; font-weight: 400; }
.header-divider { color: var(--win-input-border); margin: 0 8px; font-weight: 400; }
main { max-width: 1456px; margin: 0 auto; padding: 28px; }
.panel { border: 1px solid var(--win-border); border-radius: var(--radius); background: var(--win-btn-bg); box-shadow: var(--shadow-panel); }
.login-panel, .session-panel { width: 100%; max-width: 420px; margin: 64px auto; padding: 28px; }
.login-panel > p { margin-top: 8px; }
.login-panel form { margin: 24px 0; }
.login-panel form > button { width: 100%; margin-top: 16px; }
.session-panel button { margin-top: 20px; }
.session-panel h1 { font-size: 20px; margin-bottom: 12px; }
.page-heading { display: flex; justify-content: space-between; align-items: flex-end; gap: 16px; margin-bottom: 20px; }
.page-heading p { margin-top: 4px; }
.summary { color: var(--win-text-muted); font-variant-numeric: tabular-nums; }
.generation-panel { padding: 20px 24px; margin-bottom: 20px; border-top: 2px solid var(--win-blue); background: linear-gradient(180deg, var(--win-accent-soft) -130px, var(--win-btn-bg) 130px); }
.section-heading { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; margin-bottom: 16px; }
.generation-form { display: grid; grid-template-columns: 140px 160px minmax(140px, 1fr) auto; align-items: start; gap: 16px; }
.generation-form > button { margin-top: 27px; min-width: 130px; }
.codes-panel { border-top: 1px solid var(--win-border); padding-top: 20px; margin-top: 20px; }
.codes-panel .section-heading { margin-bottom: 8px; }
.code-output { display: block; font-family: var(--font-mono); line-height: 1.7; resize: vertical; min-height: 100px; max-height: 360px; margin: 12px 0; background: var(--win-bg); }
.button-row { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; }
.list-heading { padding: 20px 24px 0; }
.list-heading p { margin-top: 4px; }
.filters { display: flex; align-items: flex-start; gap: 16px; flex-wrap: wrap; padding: 0 24px 16px; }
.filters .field { min-width: 130px; }
.search-field { flex: 1; min-width: 220px !important; }
.table-scroll { width: 100%; overflow: auto; max-height: 640px; border-top: 1px solid var(--win-border); }
table { width: 100%; border-spacing: 0; font-size: 13px; text-align: left; }
th { font-weight: 600; color: var(--win-text-muted); background: var(--win-bg); position: sticky; top: 0; z-index: 2; white-space: nowrap; }
th, td { height: 44px; padding: 10px 12px; border-bottom: 1px solid var(--win-border); }
table.compact th, table.compact td { height: 36px; padding-top: 6px; padding-bottom: 6px; }
th:first-child, td:first-child { padding-left: 24px; position: sticky; left: 0; min-width: 155px; background: var(--win-btn-bg); z-index: 1; }
th:first-child { z-index: 3; background: var(--win-bg); }
tbody tr:hover td { background: var(--win-accent-soft); }
td { vertical-align: middle; transition: background 100ms; }
td:nth-child(2) { min-width: 150px; max-width: 260px; overflow-wrap: anywhere; }
td:nth-child(4), td:nth-child(6), td:nth-child(7) { white-space: nowrap; font-variant-numeric: tabular-nums; }
td:last-child { min-width: 178px; white-space: nowrap; }
td:last-child button { padding: 4px 9px; font-size: 12px; min-height: 32px; margin-right: 6px; }
.code-hint, .device { font-family: var(--font-mono); user-select: text; }
.device { display: block; max-width: 170px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.pill { display: inline-block; border-radius: 4px; padding: 2px 7px; white-space: nowrap; background: var(--win-bg); color: var(--win-text-muted); font-size: 12px; }
.pill.active { color: var(--win-success); background: var(--win-success-soft); }
.pill.disabled { color: var(--win-critical); background: var(--win-critical-soft); }
.pill.expired { color: var(--win-warning); background: var(--win-warning-soft); }
.pill.unbound { color: var(--win-blue-hover); background: var(--win-accent-soft); }
.error-text { color: var(--win-critical); margin-top: 12px; overflow-wrap: anywhere; }
.error-box { margin: 0 24px 16px; padding: 12px 16px; border: 1px solid var(--win-critical); border-radius: 4px; color: var(--win-critical); background: var(--win-critical-soft); }
.error-box p { margin-bottom: 8px; }
.list-status { padding: 0 24px 12px; font-size: 12px; }
.empty-state { padding: 36px 24px; text-align: center; border-bottom: 1px solid var(--win-border); }
.empty-state p { margin: 8px 0 16px; }
.pagination { padding: 14px 24px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.footer-note { margin-top: 16px; }
dialog { border: 1px solid var(--win-border); border-radius: 8px; background: var(--win-btn-bg); color: var(--win-text); padding: 24px; width: min(460px, calc(100% - 32px)); box-shadow: var(--shadow-dialog); }
dialog::backdrop { background: rgb(var(--shadow-rgb) / .35); backdrop-filter: blur(2px); }
dialog h2 { margin-bottom: 8px; }
dialog label { margin-top: 24px; }
dialog input + p { margin-top: 10px; }
.dialog-actions { display: flex; gap: 8px; justify-content: flex-end; margin-top: 24px; }
.toast { position: fixed; z-index: 5; bottom: 24px; left: 50%; transform: translateX(-50%); max-width: min(560px, calc(100% - 32px)); padding: 12px 20px; border: 1px solid var(--win-border); border-radius: var(--radius); background: var(--win-text); color: var(--win-btn-bg); box-shadow: var(--shadow-dialog); overflow-wrap: anywhere; }
.skeleton { display: block; width: 80%; height: 12px; border-radius: 3px; background: linear-gradient(90deg, var(--win-bg) 25%, var(--win-panel) 50%, var(--win-bg) 75%); background-size: 200% 100%; animation: shimmer 1.6s linear infinite; }
@keyframes shimmer { to { background-position: -200% 0; } }
@media (max-width: 850px) {
  .generation-form { grid-template-columns: 1fr 1fr; }
  .generation-form > button { align-self: start; margin-top: 27px; }
  .note-field { min-width: 0; }
}
@media (max-width: 540px) {
  .header-inner { padding: 8px 16px; gap: 8px; font-size: 13px; }
  .header-divider { margin: 0 4px; }
  main { padding: 20px 16px; }
  h1 { font-size: 22px; }
  .page-heading { align-items: flex-start; flex-direction: column; gap: 8px; }
  .generation-panel { padding: 16px; }
  .generation-form { grid-template-columns: 1fr; }
  .generation-form > button { margin-top: 0; width: 100%; }
  button, input, select { min-height: 44px; }
  .list-heading { padding: 16px 16px 0; }
  .filters { padding: 0 16px 16px; gap: 12px; }
  .filters .field { flex: 1; min-width: 0; }
  .filters .search-field { flex-basis: 100%; min-width: 0 !important; }
  .login-panel, .session-panel { margin: 24px auto; padding: 20px; }
  .list-status { padding-left: 16px; padding-right: 16px; }
  .error-box { margin-left: 16px; margin-right: 16px; }
  .pagination { padding: 12px 16px; flex-wrap: wrap; }
  td:last-child button { min-height: 44px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}