* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  font-family: 'Inter', 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: #0f0f1a;
  color: #e0e0ff;
}

body {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  background-attachment: fixed;
  min-height: 100vh;
  margin: 0;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
  display: flex;
  justify-content: center;
  align-items: center;
  overflow-x: hidden;
  overflow-y: auto;
  position: relative;
}

/* 深色背景光點 */
body::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background:
    radial-gradient(circle at 20% 80%, rgba(80, 100, 200, 0.25) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(100, 180, 255, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 50% 50%, rgba(150, 150, 255, 0.1) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
  animation: float 18s ease-in-out infinite;
}

/* 深色毛玻璃容器 */
.container {
  background: rgba(20, 20, 40, 0.4);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 36px 32px;
  border-radius: 20px;
  box-shadow:
    0 8px 32px rgba(0, 0, 0, 0.3),
    0 0 0 1px rgba(100, 120, 255, 0.1) inset;
  max-width: 440px;
  width: 100%;
  text-align: center;
  animation: slideIn 0.9s cubic-bezier(0.16, 1, 0.3, 1) forwards;
  transform: translateY(20px);
  opacity: 0;
}

h1 {
  font-size: 1.75rem;
  margin-bottom: 24px;
  color: #e0e6ff;
  font-weight: 700;
  letter-spacing: -0.5px;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
  animation: fadeInText 1s ease-out 0.3s forwards;
  opacity: 0;
}

form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

label {
  font-size: 0.95rem;
  color: rgba(220, 230, 255, 0.9);
  text-align: left;
  font-weight: 500;
  margin-bottom: 6px;
  display: block;
}

.input-wrapper {
  position: relative;
}

input[type="text"] {
  width: 100%;
  padding: 14px 16px;
  border: none;
  border-radius: 12px;
  font-size: 1rem;
  background: rgba(40, 40, 70, 0.5);
  color: #e0e6ff;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow:
    0 4px 12px rgba(0, 0, 0, 0.2),
    0 0 0 1px rgba(100, 120, 255, 0.2) inset;
}

input[type="text"]::placeholder {
  color: rgba(180, 190, 255, 0.6);
  font-weight: 500;
}

input[type="text"]:focus {
  outline: none;
  background: rgba(50, 50, 90, 0.7);
  box-shadow:
    0 0 0 3px rgba(100, 150, 255, 0.4),
    0 8px 25px rgba(0, 0, 0, 0.25);
  transform: translateY(-1px);
}

button {
  margin-top: 8px;
  padding: 14px 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow:
    0 6px 20px rgba(102, 126, 234, 0.4),
    0 0 0 1px rgba(255, 255, 255, 0.1) inset;
  position: relative;
  overflow: hidden;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -75%;
  width: 50%;
  height: 100%;
  background: linear-gradient(120deg, transparent, rgba(255, 255, 255, 0.6), transparent);
  animation: shine 2.5s infinite;
}

button:hover {
  transform: translateY(-3px);
  box-shadow:
    0 12px 30px rgba(102, 126, 234, 0.5),
    0 0 0 1px rgba(255, 255, 255, 0.2) inset;
}

button:hover::before {
  left: 100%;
}

button:active {
  transform: translateY(-1px);
}

p.error {
  margin-top: 12px;
  font-size: 0.875rem;
  color: #ff6b6b;
  font-weight: 500;
  animation: fadeInText 0.8s ease-out forwards;
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.2);
  opacity: 0;
}

input[type="text"]::placeholder {
  color: rgba(180, 190, 255, 0.6);
  font-weight: 500;
  font-style: italic;
}

/* 動畫 */
@keyframes slideIn {
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInText {
  to { opacity: 1; transform: translateY(0); }
}

@keyframes float {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-15px) rotate(0.5deg); }
}

/* 手機適配 */
@media (max-width: 480px) {
  .container {
    padding: 24px 20px;
    margin: 16px;
    border-radius: 18px;
  }
  h1 { font-size: 1.5rem; }
  input[type="text"] { padding: 13px 15px; font-size: 0.95rem; }
  button { padding: 13px 18px; font-size: 0.95rem; }
  label { font-size: 0.9rem; }
  p.error { font-size: 0.8rem; }
}

@keyframes shine {
  0% { left: -75%; }
  100% { left: 125%; }
}