:root {
  --surface: #0c1324;
  --surface-container-low: #151b2d;
  --surface-container-high: #23293c;
  --surface-container-highest: #2e3447;
  --surface-bright: #3a4156;
  --primary: #45e180;
  --primary-container: #00bf63;
  --on-surface: #dce1fb;
  --on-surface-variant: #bbcbbb;
  --on-primary-fixed: #000000;
  --tertiary: #bec7d4;
  --outline-variant: rgba(255, 255, 255, 0.15);
  --error-bg: rgba(239, 68, 68, 0.1);
  --error-text: #ef4444;
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--surface);
  color: var(--on-surface-variant);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
  line-height: 1.5;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Space Grotesk', sans-serif;
  color: var(--on-surface);
  letter-spacing: -0.02em;
}

.background-elements {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  overflow: hidden;
}

.glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.15;
}

.glow-1 {
  width: 600px;
  height: 600px;
  background: var(--primary);
  top: -200px;
  left: -200px;
}

.glow-2 {
  width: 500px;
  height: 500px;
  background: var(--primary-container);
  bottom: -200px;
  right: -100px;
}

.auth-container {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 440px;
  padding: 24px;
}

/* Luminous Tray & Floating Element */
.glass-panel {
  background: rgba(46, 52, 71, 0.6); /* surface-container-highest with transparency */
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-radius: 24px;
  padding: 40px 24px; /* Internal visual padding */
  box-shadow: 0 20px 40px rgba(0, 191, 99, 0.08), inset 0 2px 0 rgba(69, 225, 128, 0.1); /* top-weighted inner shadow */
  border: none; /* No 1px lines */
}

.brand {
  text-align: center;
  margin-bottom: 40px;
}

.logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  background: var(--surface-container-highest);
  border-radius: 16px;
  margin-bottom: 24px;
  color: var(--primary);
  box-shadow: 0 10px 20px rgba(0, 191, 99, 0.05);
}

.brand h1 {
  font-size: 28px;
  font-weight: 500;
  margin-bottom: 8px;
}

.brand .subtitle {
  color: var(--on-surface-variant);
  font-size: 14px;
}

.input-group {
  margin-bottom: 24px;
}

.input-group label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--on-surface-variant);
}

.input-group input {
  width: 100%;
  padding: 14px 16px;
  background: var(--surface-container-highest);
  border: none;
  border-radius: 12px;
  color: var(--on-surface);
  font-size: 15px;
  font-family: 'Inter', sans-serif;
  transition: all 0.2s ease;
  outline: none;
}

.input-group input:focus {
  background: var(--surface-bright);
  box-shadow: 0 0 0 2px rgba(69, 225, 128, 0.3);
}

.input-group input::placeholder {
  color: var(--tertiary);
  opacity: 0.5;
}

.btn {
  width: 100%;
  padding: 14px;
  border-radius: 0.75rem;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  border: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-family: 'Inter', sans-serif;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-container));
  color: var(--on-primary-fixed);
  box-shadow: 0 10px 20px rgba(0, 191, 99, 0.1);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 12px 24px rgba(0, 191, 99, 0.15);
}

.btn-secondary {
  background: transparent;
  color: var(--primary);
  border: 1px solid rgba(255, 255, 255, 0.03); /* Ghost border rule: outline-variant 20%, but the rule said "If border essential.. use outline variant 15%". I'll use box-shadow to simulate ghost border to avoid layout shift, or actual border. */
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.btn-secondary:hover {
  background: var(--surface-container-low);
  transform: translateY(-1px);
}

.social-auth-section {
  margin-top: 32px;
  padding-top: 32px;
  /* Visual separation via margin and background shift logic if needed, but here we just use whitespace as per No-Divider rule */
}

.social-auth-label {
  text-align: center;
  font-size: 13px;
  color: var(--on-surface-variant);
  margin-bottom: 24px;
}

.social-auth {
  display: flex;
  gap: 16px;
  flex-direction: column;
}

.error-banner {
  background: var(--error-bg);
  color: var(--error-text);
  padding: 16px;
  border-radius: 12px;
  font-size: 14px;
  margin-bottom: 24px;
  border: 1px solid rgba(239, 68, 68, 0.2);
}

.hidden {
  display: none !important;
}

.spinner-container {
  text-align: center;
  margin-bottom: 24px;
  color: var(--on-surface-variant);
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--surface-container-highest);
  border-radius: 50%;
  border-top-color: var(--primary);
  animation: spin 1s ease-in-out infinite;
  margin: 0 auto 16px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}