<!-- style.css modern design -->
<style>
  :root {
    --bg-color: #0f1115;
    --card-bg: #1c1e26;
    --accent: #10b981;
    --text-light: #f3f4f6;
    --text-muted: #9ca3af;
    --radius: 12px;
  }
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-color);
    color: var(--text-light);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
  }
  .container {
    width: 100%;
    max-width: 420px;
    background: var(--card-bg);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.1);
  }
  h2 {
    text-align: center;
    color: var(--accent);
    margin-bottom: 20px;
    font-size: 24px;
  }
  label {
    display: block;
    margin-bottom: 5px;
    color: var(--text-muted);
    font-weight: 500;
  }
  input[type="text"],
  input[type="password"],
  input[type="number"] {
    width: 100%;
    padding: 10px 12px;
    margin-bottom: 15px;
    background: #111317;
    border: 1px solid #2c2f36;
    border-radius: var(--radius);
    color: var(--text-light);
    font-size: 15px;
  }
  input[type="submit"] {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: var(--radius);
    background-color: var(--accent);
    color: #000;
    font-weight: bold;
    font-size: 16px;
    cursor: pointer;
    transition: background 0.3s;
  }
  input[type="submit"]:hover {
    background-color: #0ea873;
  }
  ul {
    list-style: none;
    padding: 0;
  }
  li {
    background: #111317;
    border: 1px solid #2c2f36;
    padding: 12px 16px;
    margin-bottom: 10px;
    border-radius: var(--radius);
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
  }
  a:hover {
    text-decoration: underline;
  }
  p {
    margin-bottom: 12px;
    font-size: 14px;
    color: var(--text-muted);
  }
  
  .flash-message {
  background-color: #10b981;
  color: white;
  padding: 12px 20px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: bold;
  text-align: center;
  margin-bottom: 24px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

</style>