:root {
        color-scheme: light;
        --bg: #eef4f7;
        --panel: #ffffff;
        --line: #cfd9e2;
        --text: #17324e;
        --muted: #45637d;
        --brand: #234469;
        --brand-hover: #1b3654;
        --accent: #5ca395;
        --accent-soft: rgba(92, 163, 149, 0.18);
      }
      * { box-sizing: border-box; }
      body {
        margin: 0;
        min-height: 100vh;
        display: grid;
        place-items: center;
        padding: 24px;
        font-family: Arial, sans-serif;
        color: var(--text);
        background:
          radial-gradient(circle at top right, rgba(92, 163, 149, 0.22), transparent 30%),
          radial-gradient(circle at bottom left, rgba(35, 68, 105, 0.16), transparent 32%),
          linear-gradient(180deg, #eff5f8 0%, #e6edf3 100%);
      }
      main {
        width: min(100%, 640px);
        padding: 44px;
        border: 1px solid var(--line);
        border-radius: 8px;
        background: var(--panel);
        box-shadow: 0 24px 48px rgba(35, 68, 105, 0.12);
      }
      .brand {
        margin: 0 auto 20px;
        width: fit-content;
        padding: 10px 14px;
        border-radius: 8px;
        font-weight: 800;
        letter-spacing: 0.08em;
        color: var(--brand);
        background: rgba(35, 68, 105, 0.08);
      }
      h1 {
        margin: 0 0 12px;
        font-size: 28px;
        text-align: center;
        color: var(--brand);
      }
      p {
        margin: 0 0 20px;
        color: var(--muted);
        line-height: 1.5;
        text-align: center;
      }
      .error {
        margin: 0 0 16px;
        padding: 12px 14px;
        border-radius: 8px;
        background: #fff1f2;
        color: #b42318;
        font-size: 14px;
      }
      label {
        display: block;
        margin-bottom: 8px;
        font-size: 14px;
        font-weight: 700;
      }
      input, button {
        width: 100%;
        border-radius: 8px;
        font-size: 16px;
      }
      input {
        margin-bottom: 16px;
        padding: 14px 16px;
        border: 1px solid var(--line);
        background: #fbfdfe;
      }
      input:focus {
        outline: 2px solid var(--accent-soft);
        border-color: var(--accent);
      }
      button {
        border: 0;
        padding: 14px 16px;
        background: linear-gradient(135deg, var(--brand) 0%, var(--accent) 100%);
        color: #fff;
        font-weight: 700;
        cursor: pointer;
        box-shadow: 0 12px 24px rgba(35, 68, 105, 0.18);
      }
      button:hover {
        background: linear-gradient(135deg, var(--brand-hover) 0%, #4e9185 100%);
      }
      .hint {
        margin-top: 16px;
        font-size: 13px;
      }