:root {
  --bg-color: linear-gradient(to right, #6a11cb, #2575fc);
  --text-color: #ffffff;
  --card-bg: rgba(255, 255, 255, 0.1);
  --card-border: rgba(255, 255, 255, 0.18);
  --btn-bg: #4a90e2;
  --btn-shadow: rgba(74, 144, 226, 0.75);
}

body.light-mode {
  --bg-color: linear-gradient(to right, #fdfbfb, #ebedee);
  --text-color: #333333;
  --card-bg: rgba(0, 0, 0, 0.05);
  --card-border: rgba(0, 0, 0, 0.1);
  --btn-bg: #2575fc;
  --btn-shadow: rgba(37, 117, 252, 0.3);
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--bg-color);
    background-attachment: fixed;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text-color);
    margin: 0;
    transition: background 0.3s, color 0.3s;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 10px 15px;
    cursor: pointer;
    border-radius: 20px;
    border: 1px solid var(--text-color);
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-color);
    font-weight: bold;
    backdrop-filter: blur(4px);
    transition: all 0.3s;
}

#theme-toggle:hover {
    transform: scale(1.05);
    background: rgba(255, 255, 255, 0.2);
}