@import url('https://fonts.googleapis.com/css2?family=Sarabun:wght@300;400;500;600;700&display=swap');

  :root {
    --accent: #e67e22;
    --accent-dark: #bf6418;
    --ink: #202124;
    --muted: #687076;
    --line: #dde3ea;
    --panel: #ffffff;
    --bg: #f4f6f8;
  }

  * { box-sizing: border-box; }

  body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: Sarabun, Arial, sans-serif;
    font-size: 14px;
  }

  .navbar {
    background: var(--accent);
    padding: 14px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    box-shadow: 0 2px 8px rgba(30, 42, 54, 0.1);
  }

  .navbar-title {
    font-size: 18px;
    font-weight: 700;
    color: #fff;
    margin: 0;
  }

  .navbar-menu {
    display: flex;
    gap: 10px;
  }

  .navbar-menu a,
  .navbar-menu button {
    appearance: none;
    border: 1px solid rgba(255,255,255,0.4);
    background: rgba(255,255,255,0.15);
    color: #fff;
    padding: 8px 16px;
    border-radius: 4px;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.2s;
  }

  .navbar-menu a:hover,
  .navbar-menu button:hover {
    background: rgba(255,255,255,0.25);
  }

  .navbar-menu a.active {
    background: rgba(255,255,255,0.3);
    border-color: rgba(255,255,255,0.6);
  }

  .shell {
    width: min(1180px, calc(100vw - 32px));
    margin: 0 auto;
    padding: 24px 0 48px;
  }

  .topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 18px;
  }

  h1 {
    margin: 0;
    font-size: 24px;
    line-height: 1.25;
  }
  
  h1 a {
    color: #e67e22;
  }

  .doc-number {
    color: var(--muted);
    font-size: 13px;
    margin-top: 3px;
  }

  .actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
  }

  .invoice-picker {
    align-items: flex-end;
    display: flex;
    gap: 8px;
  }

  .invoice-picker label {
    margin-bottom: 4px;
  }

  .invoice-picker select {
    min-width: min(360px, 55vw);
  }

  .button,
  button {
    appearance: none;
    border: 1px solid var(--accent);
    background: var(--accent);
    color: #fff;
    border-radius: 6px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 38px;
    padding: 8px 14px;
    font: 600 14px/1 Sarabun, Arial, sans-serif;
    text-decoration: none;
  }

  .button.secondary,
  button.secondary {
    background: #fff;
    color: var(--accent-dark);
  }

  .button.danger,
  button.danger {
    border-color: #d74d43;
    background: #fff;
    color: #b3362e;
  }

  .message,
  .error {
    border-radius: 6px;
    margin: 0 0 16px;
    padding: 11px 13px;
    font-weight: 600;
  }

  .message {
    background: #e7f8ee;
    border: 1px solid #b7e4c7;
    color: #216e3a;
  }

  .error {
    background: #fff0f0;
    border: 1px solid #f1b3ae;
    color: #9c2d25;
  }

  form {
    display: grid;
    gap: 16px;
  }

  .grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .panel {
    background: var(--panel);
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 18px;
    box-shadow: 0 8px 20px rgba(30, 42, 54, 0.05);
  }

  .panel.full {
    grid-column: 1 / -1;
  }

  .panel-header {
    align-items: center;
    display: flex;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 14px;
  }

  h2 {
    margin: 0;
    font-size: 17px;
  }

  .fields {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }

  .field.full {
    grid-column: 1 / -1;
  }

  label {
    color: #343a40;
    display: block;
    font-size: 12px;
    font-weight: 700;
    margin-bottom: 5px;
  }

  input,
  select,
  textarea {
    width: 100%;
    border: 1px solid #cfd7df;
    border-radius: 6px;
    background: #fff;
    color: var(--ink);
    font: 400 14px/1.45 Sarabun, Arial, sans-serif;
    padding: 8px 10px;
  }

  textarea {
    min-height: 92px;
    resize: vertical;
  }

  .repeat-list {
    display: grid;
    gap: 12px;
  }

  .repeat-row {
    background: #fbfcfd;
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 14px;
  }

  .row-title {
    align-items: center;
    display: flex;
    justify-content: space-between;
    gap: 10px;
    margin-bottom: 12px;
  }

  .row-title strong {
    color: var(--accent-dark);
    font-size: 14px;
  }

  .item-grid {
    display: grid;
    grid-template-columns: 1.6fr 0.55fr 0.75fr 0.65fr 0.5fr 0.8fr;
    gap: 10px;
  }

  .item-detail-field {
    grid-column: 1 / -1;
  }

  .bank-grid {
    display: grid;
    grid-template-columns: 0.8fr 0.8fr 1fr 1fr 1.4fr;
    gap: 10px;
  }

  .sticky-save {
    position: sticky;
    bottom: 0;
    z-index: 3;
    background: rgba(244, 246, 248, 0.94);
    border-top: 1px solid var(--line);
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 14px 0 0;
  }

  .panel-note {
    color: var(--muted);
    font-size: 12px;
    font-weight: 500;
  }

  .fields.computed {
    margin-top: 14px;
    padding-top: 14px;
    border-top: 1px dashed var(--line);
  }

  input[readonly] {
    background: #f6f8fa;
    color: #55606a;
    cursor: default;
    font-weight: 600;
  }

  .preview-frame {
    width: 100%;
    height: 70vh;
    min-height: 460px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #e8e8e8;
  }

  button:disabled,
  .button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
  }

  .login-shell {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
  }

  .login-card {
    width: min(360px, 100%);
    background: var(--panel);
    border: 1px solid var(--line);
    border-radius: 10px;
    padding: 28px 26px 26px;
    box-shadow: 0 12px 30px rgba(30, 42, 54, 0.08);
    display: block;
  }

  .login-card h1 {
    color: var(--accent);
    margin-bottom: 4px;
  }

  .login-hint {
    color: var(--muted);
    margin: 0 0 18px;
  }

  .login-card label {
    margin-top: 6px;
  }

  .login-card input {
    margin-bottom: 16px;
  }

  .login-card button {
    width: 100%;
  }

  @media (max-width: 860px) {
    .topbar,
    .invoice-picker,
    .grid,
    .fields,
    .item-grid,
    .bank-grid {
      grid-template-columns: 1fr;
    }

    .topbar {
      align-items: stretch;
      display: grid;
    }

    .actions {
      justify-content: stretch;
    }

    .actions .button,
    .actions button {
      flex: 1;
    }
  }