:root {
  --bg-gradient: linear-gradient(135deg, #006d77, #83c5be, #3a86ff);
  --text-color: #f0f8ff;
  --box-bg: rgba(0, 77, 77, 0.2);
  --button-bg: #00b4d8;
  --button-hover: #0077b6;
}

body.light {
  --bg-gradient: linear-gradient(135deg, #caf0f8, #ade8f4, #90e0ef);
  --text-color: #003344;
  --box-bg: rgba(255, 255, 255, 0.6);
  --button-bg: #0077b6;
  --button-hover: #005f8d;
}

body {
  font-family: 'Segoe UI', sans-serif;
  background: var(--bg-gradient);
  color: var(--text-color);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  background-size: 400% 400%;
  animation: bgShift 15s ease infinite;
  transition: all 0.5s ease;
}

@keyframes bgShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.container {
  background-color: var(--box-bg);
  backdrop-filter: blur(8px);
  padding: 30px;
  border-radius: 15px;
  text-align: center;
  width: 90%;
  max-width: 480px;
  box-shadow: 0 0 25px rgba(0, 0, 0, 0.3);
}

h1 {
  font-size: 1.5rem;
  margin-bottom: 20px;
}

input {
  padding: 12px;
  font-size: 16px;
  width: 100%;
  margin: 15px 0;
  border: none;
  border-radius: 10px;
  outline: none;
  box-shadow: 0 0 5px rgba(0,0,0,0.2);
}

button {
  padding: 12px 24px;
  font-size: 16px;
  background-color: var(--button-bg);
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: background-color 0.3s ease;
  margin-top: 10px;
}

button:hover {
  background-color: var(--button-hover);
}

.theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  font-size: 22px;
  background: none;
  color: var(--text-color);
}

.advice-box {
  background: rgba(255, 255, 255, 0.15);
  padding: 20px;
  border-radius: 12px;
  margin-top: 20px;
  min-height: 120px;
  opacity: 0;
  transform: translateY(10px);
  transition: all 0.4s ease;
  font-size: 1.05rem;
  color: var(--text-color);
}

.advice-box.show {
  opacity: 1;
  transform: translateY(0);
}

.advice-box em {
  display: inline-block;
  animation: emojiPop 1s ease infinite alternate;
}

@keyframes emojiPop {
  0% { transform: translateY(0); }
  100% { transform: translateY(-4px); }
}