:root {
  --bg-gradient: linear-gradient(to right, #fdfbfb, #ebedee);
  --text-color: #333;
  --main-bg: rgba(0, 0, 0, 0.05);
  --main-border: rgba(0, 0, 0, 0.1);
  --h1-color: #222;
  --h1-shadow: 0 2px 5px rgba(0,0,0,0.1);
  --btn-bg: #4ca1af;
  --btn-text: #fff;
}

body.dark-mode {
  --bg-gradient: linear-gradient(to right, #2c3e50, #4ca1af);
  --text-color: #fff;
  --main-bg: rgba(255, 255, 255, 0.1);
  --main-border: rgba(255, 255, 255, 0.2);
  --h1-color: #ffffff;
  --h1-shadow: 0 2px 10px rgba(0,0,0,0.3);
  --btn-bg: #fff;
  --btn-text: #2c3e50;
}

body {
  background: var(--bg-gradient);
  color: var(--text-color);
  font-family: 'Helvetica Neue', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  position: relative;
  overflow: hidden;
  transition: background 0.3s ease, color 0.3s ease;
}

body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><filter id="n"><feTurbulence type="fractalNoise" baseFrequency="0.75" stitchTiles="stitch"/></filter><rect width="100%" height="100%" filter="url(%23n)" opacity="0.1"/></svg>');
    opacity: 0.2;
    z-index: -1;
}

main {
  text-align: center;
  background-color: var(--main-bg);
  padding: 2.5rem;
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(10px);
  border: 1px solid var(--main-border);
  transition: background-color 0.3s ease, border 0.3s ease;
}

h1 {
  color: var(--h1-color);
  font-weight: bold;
  font-size: 2.5em;
  text-shadow: var(--h1-shadow);
  transition: color 0.3s ease;
}

#generate-btn {
  background-color: var(--btn-bg);
  color: var(--btn-text);
  border: none;
  padding: 1rem 2rem;
  font-size: 1.2rem;
  font-weight: bold;
  border-radius: 50px;
  cursor: pointer;
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
  transition: transform 0.2s, background-color 0.3s, color 0.3s;
}

#generate-btn:active {
  transform: scale(0.95);
}

#theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  padding: 10px 20px;
  border-radius: 20px;
  border: none;
  background: var(--main-bg);
  color: var(--text-color);
  cursor: pointer;
  backdrop-filter: blur(10px);
  border: 1px solid var(--main-border);
  font-weight: bold;
}

#numbers-container {
  display: flex;
  flex-direction: column; /* Stack rows vertically */
  gap: 1rem; /* Space between rows */
  margin: 2.5rem 0;
}

.number-row {
  display: flex;
  justify-content: center;
  gap: 1.2rem; /* Space between numbers in a row */
}

.number {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.8rem;
  font-weight: bold;
  color: white;
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
  border: 2px solid rgba(255, 255, 255, 0.5);
  opacity: 0;
  transform: scale(0);
  animation: appear-animation 0.5s ease-out forwards, color-swirl 10s linear infinite;
  background-size: 400% 400%;
}

.number.row-1 { background: linear-gradient(45deg, #ff005c, #ff5c9d, #ff005c); background-size: 400% 400%; }
.number.row-2 { background: linear-gradient(45deg, #ff9a00, #ffc500, #ff9a00); background-size: 400% 400%; }
.number.row-3 { background: linear-gradient(45deg, #34e89e, #07f49e, #34e89e); background-size: 400% 400%; }
.number.row-4 { background: linear-gradient(45deg, #3498db, #2980b9, #3498db); background-size: 400% 400%; }
.number.row-5 { background: linear-gradient(45deg, #9b59b6, #8e44ad, #9b59b6); background-size: 400% 400%; }

@keyframes appear-animation {
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes color-swirl {
    0%{background-position:0% 50%}
    50%{background-position:100% 50%}
    100%{background-position:0% 50%}
}


#generate-btn {
  padding: 1rem 2rem;
  border: none;
  background: linear-gradient(to right, #ff416c, #ff4b2b);
  color: white;
  font-size: 1.2rem;
  font-weight: bold;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 5px 15px rgba(255, 75, 43, 0.4);
}

#generate-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(255, 75, 43, 0.6);
}