:root {
      --bg: #f7f9fb;
      --surface: #ffffff;
      --surface-soft: #f1f6f4;
      --line: #d9e2df;
      --line-strong: #b7c5c0;
      --text: #1f2622;
      --muted: #667168;
      --accent: #15756d;
      --accent-strong: #0e5f59;
      --danger: #b33a3a;
      --ok: #177245;
      --warn: #a45f12;
      --header-color: #b45309;
      --payload-color: #2463b7;
      --signature-color: #7a3db8;
      color-scheme: light;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      min-height: 100vh;
      color: var(--text);
      background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.55), rgba(255, 255, 255, 0)),
        var(--bg);
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
    }

    button,
    input,
    select,
    textarea {
      font: inherit;
    }

    button {
      cursor: pointer;
    }

    [hidden] {
      display: none !important;
    }

    .app {
      width: min(1440px, calc(100% - 32px));
      margin: 0 auto;
      padding: 24px 0 32px;
    }

    .topbar {
      display: flex;
      align-items: flex-start;
      justify-content: space-between;
      gap: 20px;
      margin-bottom: 16px;
    }

    .title-block {
      min-width: 0;
    }

    h1 {
      margin: 0;
      font-size: clamp(26px, 4vw, 42px);
      line-height: 1.08;
      letter-spacing: 0;
    }

    .subtitle {
      margin: 8px 0 0;
      color: var(--muted);
      font-size: 15px;
      line-height: 1.5;
    }

    .segmented {
      flex: 0 0 auto;
      display: grid;
      grid-template-columns: repeat(2, minmax(92px, 1fr));
      gap: 4px;
      padding: 4px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #e7eeec;
    }

    .segmented button {
      min-height: 38px;
      border: 0;
      border-radius: 6px;
      background: transparent;
      color: var(--muted);
      font-weight: 700;
      white-space: nowrap;
    }

    .segmented button.active {
      color: var(--accent-strong);
      background: #ffffff;
      box-shadow: 0 1px 4px rgba(20, 41, 31, 0.12);
    }

    .status {
      min-height: 46px;
      margin-bottom: 16px;
      padding: 12px 14px;
      border: 1px solid var(--line);
      border-left: 4px solid var(--accent);
      border-radius: 8px;
      background: var(--surface);
      color: var(--muted);
      line-height: 1.35;
    }

    .status.success {
      border-left-color: var(--ok);
      color: var(--ok);
    }

    .status.error {
      border-left-color: var(--danger);
      color: var(--danger);
    }

    .status.warn {
      border-left-color: var(--warn);
      color: var(--warn);
    }

    .workspace {
      display: grid;
      grid-template-columns: minmax(360px, 0.95fr) minmax(420px, 1.25fr);
      gap: 16px;
      align-items: stretch;
    }

    .panel {
      min-width: 0;
      overflow: hidden;
      display: flex;
      flex-direction: column;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: var(--surface);
      box-shadow: 0 14px 34px rgba(35, 51, 41, 0.08);
    }

    .panel-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      min-height: 68px;
      padding: 14px 16px;
      border-bottom: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.58);
    }

    .panel-title {
      margin: 0;
      font-size: 17px;
      line-height: 1.25;
    }

    .panel-subtitle {
      margin: 4px 0 0;
      color: var(--muted);
      font-size: 13px;
      line-height: 1.35;
    }

    .panel-actions {
      display: flex;
      flex-wrap: wrap;
      justify-content: flex-end;
      gap: 8px;
    }

    .button {
      min-height: 36px;
      padding: 0 13px;
      border: 1px solid var(--line-strong);
      border-radius: 7px;
      background: #ffffff;
      color: var(--text);
      font-weight: 700;
      transition: border-color 0.16s ease, background 0.16s ease, color 0.16s ease, transform 0.16s ease;
    }

    .button:hover {
      border-color: var(--accent);
      color: var(--accent-strong);
    }

    .button:active {
      transform: translateY(1px);
    }

    .button.primary {
      border-color: var(--accent);
      background: var(--accent);
      color: #ffffff;
    }

    .button.primary:hover {
      border-color: var(--accent-strong);
      background: var(--accent-strong);
      color: #ffffff;
    }

    .button.subtle {
      background: var(--surface-soft);
    }

    .button.danger {
      border-color: rgba(179, 58, 58, 0.4);
      color: var(--danger);
    }

    .button.small {
      min-height: 30px;
      padding: 0 10px;
      font-size: 12px;
    }

    .icon-button {
      width: 36px;
      min-width: 36px;
      padding: 0;
      display: inline-grid;
      place-items: center;
      font-size: 0;
    }

    .icon-button.small {
      width: 30px;
      min-width: 30px;
      padding: 0;
    }

    .copy-icon {
      position: relative;
      width: 15px;
      height: 17px;
      display: inline-block;
    }

    .copy-icon::before,
    .copy-icon::after {
      content: "";
      position: absolute;
      width: 11px;
      height: 13px;
      border: 1.8px solid currentColor;
      border-radius: 3px;
      background: currentColor;
      opacity: 0.2;
    }

    .copy-icon::before {
      left: 0;
      top: 0;
    }

    .copy-icon::after {
      right: 0;
      bottom: 0;
      background: #ffffff;
      opacity: 1;
    }

    textarea {
      width: 100%;
      min-width: 0;
      border: 0;
      outline: none;
      resize: vertical;
      background: #ffffff;
      color: var(--text);
      font-family: "Cascadia Code", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
      font-size: 14px;
      line-height: 1.55;
      tab-size: 2;
    }

    .code-shell {
      position: relative;
      overflow: hidden;
      background: #ffffff;
    }

    .code-highlight {
      position: absolute;
      inset: 0;
      z-index: 0;
      margin: 0;
      overflow: hidden;
      pointer-events: none;
      white-space: pre-wrap;
      overflow-wrap: anywhere;
      word-break: break-word;
      color: var(--text);
      font-family: "Cascadia Code", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
      font-size: 14px;
      line-height: 1.55;
      tab-size: 2;
    }

    .code-textarea {
      position: relative;
      z-index: 1;
      display: block;
      color: transparent;
      caret-color: var(--text);
      background: transparent;
      overflow-wrap: anywhere;
      word-break: break-word;
    }

    .code-textarea::selection {
      color: transparent;
      background: rgba(21, 117, 109, 0.2);
    }

    textarea::placeholder,
    input::placeholder {
      color: #9aa39b;
    }

    textarea:focus,
    input:focus,
    select:focus {
      box-shadow: inset 0 0 0 2px rgba(21, 117, 109, 0.25);
    }

    .token-shell {
      flex: 1 1 auto;
      min-height: 520px;
    }

    .plain-token-shell .token-highlight {
      display: none;
    }

    .token-highlight {
      padding: 16px;
    }

    .token-textarea {
      min-height: 520px;
      height: 100%;
      padding: 16px;
      word-break: break-all;
      color: var(--text);
      background: #ffffff;
      caret-color: auto;
    }

    .token-editor {
      flex: 1 1 auto;
      min-height: 520px;
      background: #ffffff;
    }

    .token-editor .CodeMirror {
      height: auto;
      min-height: 520px;
      font-family: "Cascadia Code", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
      font-size: 14px;
      line-height: 1.55;
      color: var(--text);
    }

    .token-editor .CodeMirror-scroll {
      min-height: 520px;
    }

    .token-editor .CodeMirror-lines {
      padding: 16px 0;
    }

    .token-editor .CodeMirror pre.CodeMirror-line,
    .token-editor .CodeMirror pre.CodeMirror-line-like {
      padding: 0 16px;
      word-break: break-all;
      overflow-wrap: anywhere;
      white-space: pre-wrap;
    }

    .token-editor .cm-jwt-header {
      color: var(--header-color);
    }

    .token-editor .cm-jwt-payload {
      color: var(--payload-color);
    }

    .token-editor .cm-jwt-signature {
      color: var(--signature-color);
    }

    .token-editor .cm-jwt-dot {
      color: #89938d;
      font-weight: 700;
    }

    .token-editor .CodeMirror-focused {
      box-shadow: inset 0 0 0 2px rgba(21, 117, 109, 0.25);
    }

    .editor-section {
      border-bottom: 1px solid var(--line);
    }

    .editor-section:last-child {
      border-bottom: 0;
    }

    .section-heading {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      padding: 10px 16px;
      border-bottom: 1px solid var(--line);
      background: var(--surface-soft);
    }

    .section-name {
      display: flex;
      align-items: center;
      gap: 8px;
      min-width: 0;
      color: var(--muted);
      font-size: 13px;
      font-weight: 800;
      letter-spacing: 0.02em;
      text-transform: uppercase;
    }

    .dot {
      width: 9px;
      height: 9px;
      flex: 0 0 auto;
      border-radius: 50%;
      background: currentColor;
    }

    .section-name.header {
      color: var(--header-color);
    }

    .section-name.payload {
      color: var(--payload-color);
    }

    .section-name.signature {
      color: var(--signature-color);
    }

    .json-textarea {
      min-height: 210px;
      padding: 14px 16px 16px;
    }

    .json-shell {
      min-height: 210px;
    }

    .json-highlight,
    .json-textarea {
      padding: 14px 16px 16px;
    }

    .json-output {
      min-height: 140px;
      padding: 14px 16px 16px;
      margin: 0;
      background: #ffffff;
      color: var(--text);
      font-family: "Cascadia Code", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
      font-size: 14px;
      line-height: 1.55;
      white-space: pre-wrap;
      overflow-wrap: anywhere;
      word-break: break-word;
      tab-size: 2;
    }

    .header-output {
      min-height: 92px;
    }

    .payload-output {
      min-height: 150px;
    }

    .copy-source {
      position: absolute;
      width: 1px;
      height: 1px;
      opacity: 0;
      pointer-events: none;
    }

    .jwt-header-part,
    .json-key {
      color: var(--header-color);
    }

    .jwt-payload-part,
    .json-string {
      color: var(--payload-color);
    }

    .jwt-signature-part,
    .json-number {
      color: var(--signature-color);
    }

    .jwt-dot,
    .json-punctuation {
      color: #89938d;
    }

    .json-literal {
      color: var(--accent-strong);
      font-weight: 700;
    }

    .json-exp-time {
      position: relative;
      cursor: help;
      text-decoration: underline dotted rgba(122, 61, 184, 0.7);
      text-underline-offset: 3px;
    }

    .custom-tooltip {
      position: fixed;
      z-index: 1000;
      max-width: min(280px, calc(100vw - 24px));
      padding: 8px 10px;
      border: 1px solid rgba(31, 38, 34, 0.14);
      border-radius: 7px;
      background: #1f2622;
      color: #ffffff;
      box-shadow: 0 12px 28px rgba(31, 38, 34, 0.24);
      font-size: 13px;
      font-weight: 700;
      line-height: 1.25;
      opacity: 0;
      pointer-events: none;
      transform: translateY(4px);
      transition: opacity 0.12s ease, transform 0.12s ease;
      white-space: nowrap;
    }

    .custom-tooltip.visible {
      opacity: 1;
      transform: translateY(0);
    }

    .signature-box,
    .form-block {
      display: grid;
      gap: 12px;
      padding: 14px 16px 16px;
    }

    .form-grid {
      display: grid;
      grid-template-columns: minmax(160px, 240px) minmax(220px, 1fr);
      gap: 12px;
      align-items: end;
    }

    .field {
      display: grid;
      gap: 6px;
      min-width: 0;
    }

    label,
    .field-label {
      color: var(--muted);
      font-size: 13px;
      font-weight: 700;
    }

    input,
    select {
      width: 100%;
      min-height: 38px;
      min-width: 0;
      border: 1px solid var(--line-strong);
      border-radius: 7px;
      background: #ffffff;
      color: var(--text);
      padding: 0 11px;
      outline: none;
    }

    .checkbox-line {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      width: fit-content;
      min-height: 34px;
      color: var(--muted);
      font-size: 13px;
      font-weight: 700;
    }

    .checkbox-line input {
      width: 16px;
      min-height: 16px;
      padding: 0;
      accent-color: var(--accent);
    }

    .signature-meta {
      min-height: 38px;
      padding: 10px 12px;
      border: 1px solid var(--line);
      border-radius: 7px;
      background: #ffffff;
      color: var(--muted);
      font-size: 13px;
      line-height: 1.4;
      word-break: break-word;
    }

    .signature-meta.success {
      color: var(--ok);
      border-color: rgba(23, 114, 69, 0.35);
      background: #f1faf4;
    }

    .signature-meta.error {
      color: var(--danger);
      border-color: rgba(179, 58, 58, 0.35);
      background: #fff5f4;
    }

    .signature-meta.warn {
      color: var(--warn);
      border-color: rgba(164, 95, 18, 0.35);
      background: #fff8ed;
    }

    .footer-actions {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      padding: 14px 16px;
      border-top: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.58);
    }

    @media (max-width: 980px) {
      .workspace {
        grid-template-columns: 1fr;
      }

      .token-textarea {
        min-height: 320px;
      }
    }

    @media (max-width: 720px) {
      .app {
        width: min(100% - 20px, 720px);
        padding: 14px 0 24px;
      }

      .topbar {
        display: grid;
      }

      .segmented {
        width: 100%;
      }

      .panel-header,
      .section-heading,
      .footer-actions {
        align-items: stretch;
        flex-direction: column;
      }

      .panel-actions {
        justify-content: flex-start;
      }

      .form-grid {
        grid-template-columns: 1fr;
      }

      .button {
        flex: 1 1 auto;
      }

      .icon-button {
        flex: 0 0 36px;
      }

      .icon-button.small {
        flex-basis: 30px;
      }
    }