:root {
      color-scheme: light;
      --bg: #f7f8f5;
      --panel: #ffffff;
      --text: #20231f;
      --muted: #6d7468;
      --line: #dfe4d9;
      --accent: #a7e978;
      --accent-strong: #47a85d;
      --accent-line: #8fd66a;
      --accent-soft: #e7f8dc;
      --bubble-text: #111810;
      --ink-soft: #f0f2ee;
      --shadow: 0 18px 50px rgba(30, 37, 28, 0.08);
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      background: var(--bg);
      color: var(--text);
      font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
      line-height: 1.5;
    }

    .app-header,
    main {
      max-width: 1120px;
      width: calc(100% - 32px);
      margin: 0 auto;
    }

    .app-header {
      position: relative;
      display: flex;
      align-items: end;
      justify-content: space-between;
      gap: 24px;
      padding: 36px 0 20px;
    }

    h1 {
      margin: 0;
      color: var(--text);
      font-size: clamp(2.4rem, 4vw, 5.5rem);
      line-height: 0.95;
      letter-spacing: 0;
    }

    .source-editor {
      position: absolute;
      top: 10px;
      right: 0;
      font-size: 0.85rem;
      z-index: 10;
      display: flex;
      align-items: center;
      gap: 15px;
    }

    .edit-btn {
      appearance: none;
      background: none;
      border: none;
      color: var(--muted);
      cursor: pointer;
      font: inherit;
      font-weight: 600;
      line-height: 1.2;
      padding: 0;
      text-decoration: underline;
      text-underline-offset: 3px;
    }

    .source-editor a.edit-btn,
    .source-editor button.edit-btn {
      font-family: inherit;
      font-size: 0.85rem;
      font-weight: 600;
    }

    .edit-btn:hover {
      color: var(--text);
    }

    #sourceForm {
      display: flex;
      gap: 6px;
    }

    #sourceForm input {
      min-height: 28px;
      padding: 0 8px;
      font-size: 0.85rem;
      width: 240px;
    }

    #sourceForm button {
      min-height: 28px;
      padding: 0 12px;
      font-size: 0.85rem;
      background: #fbfcfa;
      border: 1px solid var(--line);
      border-radius: 4px;
      cursor: pointer;
      font-weight: 600;
      color: var(--text);
    }

    #sourceForm button:hover {
      background: var(--ink-soft);
    }

    .summary {
      color: var(--muted);
      font-size: 0.94rem;
      text-align: right;
      max-width: 360px;
    }

    .controls {
      display: grid;
      grid-template-columns: minmax(240px, 1.6fr) minmax(170px, 0.85fr) minmax(140px, 0.7fr) auto;
      gap: 12px;
      align-items: end;
      margin: 14px 0 16px;
      padding: 14px;
      background: var(--panel);
      border: 1px solid var(--line);
      border-radius: 8px;
      box-shadow: var(--shadow);
    }

    label {
      display: grid;
      gap: 6px;
      color: var(--muted);
      font-size: 0.78rem;
      font-weight: 700;
    }

    input,
    select {
      width: 100%;
      min-height: 42px;
      border: 1px solid var(--line);
      border-radius: 6px;
      background: #fbfcfa;
      color: var(--text);
      font: inherit;
      font-size: 0.95rem;
      padding: 0 12px;
    }

    select {
      -webkit-appearance: none;
      appearance: none;
      background-image:
        linear-gradient(45deg, transparent 50%, var(--text) 50%),
        linear-gradient(135deg, var(--text) 50%, transparent 50%);
      background-position:
        calc(100% - 18px) 50%,
        calc(100% - 12px) 50%;
      background-size: 7px 7px, 7px 7px;
      background-repeat: no-repeat;
      line-height: 1.2;
      padding-right: 40px;
    }

    input:focus,
    select:focus {
      outline: 2px solid rgba(31, 122, 92, 0.22);
      border-color: var(--accent);
    }

    #orderButton {
      width: 100%;
      min-height: 42px;
      border: 1px solid var(--line);
      border-radius: 6px;
      background: #fbfcfa;
      color: var(--text);
      font: inherit;
      font-size: 0.95rem;
      padding: 0 12px;
      cursor: pointer;
      transition: opacity 0.3s;
      text-align: left;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .floating-btn {
      position: fixed;
      bottom: 20px;
      left: 50%;
      transform: translateX(-50%);
      z-index: 1000;
      padding: 10px 20px;
      border-radius: 20px;
      border: 1px solid #ccc;
      background: white;
      color: black;
      cursor: pointer;
      transition: opacity 0.3s;
      font-weight: bold;
      font-family: inherit;
    }

    #toTopBtn {
      opacity: 0;
      pointer-events: none;
    }

    .checkbox {
      display: flex;
      flex-direction: row;
      align-items: center;
      min-height: 42px;
      gap: 8px;
      padding: 0 10px;
      color: var(--text);
      border: 1px solid var(--line);
      border-radius: 6px;
      background: #fbfcfa;
      font-size: 0.95rem;
      font-weight: 700;
    }

    .checkbox input {
      width: 18px;
      min-height: 18px;
      accent-color: var(--accent);
    }

    .checkbox:has(input:checked) {
      border-color: rgba(23, 131, 93, 0.45);
      background: var(--accent-soft);
    }

    .stats {
      display: grid;
      grid-template-columns: repeat(var(--stat-columns, 4), 1fr);
      gap: 10px;
      margin-bottom: 24px;
    }

    .stat {
      padding: 14px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: rgba(255, 255, 255, 0.7);
    }

    .stat strong {
      display: block;
      font-size: 1.3rem;
    }

    .stat span {
      color: var(--muted);
      font-size: 0.78rem;
      font-weight: 700;
    }

    .timeline {
      position: relative;
      padding: 0 0 120px;
    }

    .day {
      position: sticky;
      top: 0;
      z-index: 2;
      margin: 22px 0 12px;
      padding: 9px 12px;
      color: var(--muted);
      background: rgba(247, 248, 245, 0.92);
      border-bottom: 1px solid var(--line);
      -webkit-backdrop-filter: blur(8px);
      backdrop-filter: blur(8px);
      font-weight: 800;
    }

    .message {
      display: grid;
      grid-template-columns: 24px minmax(0, 1fr);
      gap: 12px;
      margin: 0 0 12px;
    }

    .rail {
      position: relative;
    }

    .rail::before {
      content: "";
      position: absolute;
      top: 0;
      bottom: -12px;
      left: 13px;
      width: 2px;
      background: var(--line);
    }

    .rail::after {
      content: "";
      position: absolute;
      top: 17px;
      left: 7px;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: var(--panel);
      border: 2px solid var(--muted);
    }

    .message.highlighted .rail::after {
      border-color: var(--accent-strong);
      background: var(--accent-strong);
      box-shadow: 0 0 0 4px rgba(23, 131, 93, 0.14);
    }

    .message.highlighted .rail::before {
      background: linear-gradient(180deg, rgba(23, 131, 93, 0.78), rgba(23, 131, 93, 0.78));
    }

    .message-body {
      min-width: 0;
      padding: 14px 16px;
      background: var(--panel);
      border: 1px solid var(--line);
      border-radius: 8px;
    }

    .message.highlighted .message-body {
      color: var(--bubble-text);
      border-color: var(--accent-line);
      background: var(--accent);
      box-shadow: 0 12px 28px rgba(52, 168, 83, 0.18);
    }

    .message-top {
      display: flex;
      justify-content: space-between;
      gap: 12px;
      margin-bottom: 8px;
    }

    .sender {
      overflow-wrap: anywhere;
    }

    time {
      flex: 0 0 auto;
      color: var(--muted);
      font-size: 0.8rem;
      white-space: nowrap;
    }

    .message.highlighted time {
      color: rgba(17, 24, 16, 0.66);
    }

    .text {
      margin: 0;
      white-space: pre-wrap;
      overflow-wrap: anywhere;
    }

    .meta,
    .badges {
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
    }

    .meta {
      margin-top: 10px;
    }

    .badge {
      display: inline-flex;
      align-items: center;
      min-height: 22px;
      padding: 2px 7px;
      color: var(--muted);
      background: var(--ink-soft);
      border-radius: 999px;
      font-size: 0.73rem;
      font-weight: 700;
    }

    .message.highlighted .badge {
      color: #0d4f22;
      background: rgba(255, 255, 255, 0.34);
    }

    .message.highlighted .sender,
    .message.highlighted .text {
      color: var(--bubble-text);
    }

    .empty {
      padding: 36px 16px;
      color: var(--muted);
      text-align: center;
      border: 1px dashed var(--line);
      border-radius: 8px;
      background: rgba(255, 255, 255, 0.55);
    }

    @media (max-width: 760px) {
      .app-header {
        display: block;
        padding-top: 48px;
      }

      h1 {
        font-size: clamp(2rem, 8vw, 3.25rem);
      }

      .source-editor a.edit-btn,
      .source-editor button.edit-btn {
        font-size: 0.85rem;
      }

      .summary {
        margin-top: 8px;
        text-align: left;
      }

      #sourceForm input {
        width: 100%;
      }

      .controls {
        grid-template-columns: repeat(2, minmax(0, 1fr));
      }

      .controls label:not(.checkbox) > span {
        display: none;
      }

      .controls .search input,
      .controls select,
      #orderButton,
      .checkbox {
        height: 54px;
        min-height: 54px;
      }

      .checkbox input {
        width: 18px;
        height: 18px;
        min-height: 18px;
        flex: 0 0 18px;
      }

      .controls .search,
      .controls label:has(#senderSelect) {
        grid-column: 1 / -1;
      }

      .stats {
        display: none;
      }

      .message {
        grid-template-columns: 18px minmax(0, 1fr);
        gap: 8px;
      }

      .rail::before {
        left: 8px;
      }

      .rail::after {
        left: 4px;
      }

      .timeline {
        padding: 0 0 120px;
      }

      .message-top {
        display: grid;
        gap: 3px;
      }

      time {
        white-space: normal;
      }
    }

    #dropOverlay {
      position: fixed;
      inset: 0;
      z-index: 9999;
      background: rgba(247, 248, 245, 0.85);
      -webkit-backdrop-filter: blur(6px);
      backdrop-filter: blur(6px);
      display: none;
      align-items: center;
      justify-content: center;
      flex-direction: column;
      color: var(--accent-strong);
      border: 6px dashed var(--accent-strong);
      border-radius: 12px;
      margin: 16px;
    }

    #dropOverlay h2 {
      font-size: 2.2rem;
      margin: 0;
      pointer-events: none;
    }