:root {
  /* HSL Color Palette - Vibrant Green (Emerald & Lime) */
  --hue-primary: 160;
  --hue-secondary: 140;
  --hue-accent: 85;

  --color-primary: hsl(var(--hue-primary), 85%, 60%);
  --color-primary-dark: hsl(var(--hue-primary), 75%, 50%);
  --color-secondary: hsl(var(--hue-secondary), 80%, 60%);
  --color-accent: hsl(var(--hue-accent), 85%, 65%);

  /* Neutral scale - sleek dark forest mode focus */
  --bg-color: hsl(160, 20%, 3%);
  --text-primary: hsl(160, 15%, 98%);
  --text-secondary: hsl(160, 10%, 80%);
  --text-muted: hsl(160, 5%, 60%);

  /* Glassmorphism Tokens - Enhanced for visibility */
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.18);
  --glass-border-light: rgba(255, 255, 255, 0.35);
  --glass-highlight: rgba(255, 255, 255, 0.12);
  --glass-shadow: 0 16px 48px 0 rgba(0, 0, 0, 0.45);

  /* Typography */
  --font-family: 'Outfit', 'Pretendard', sans-serif;

  /* Transition Constants */
  --transition-smooth: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-bounce: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-color);
  color: var(--text-primary);
  overflow: hidden; /* App container handles scroll */
  -webkit-font-smoothing: antialiased;
}

/* Ambient Animated Background */
.ambient-background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  overflow: hidden;
  background: var(--bg-color);
}

.blob {
  position: absolute;
  filter: blur(100px);
  opacity: 0.5;
  border-radius: 50%;
  animation: float 20s infinite ease-in-out alternate;
}

.blob-1 {
  width: 400px;
  height: 400px;
  background: var(--color-primary);
  top: -10%;
  left: -10%;
  animation-delay: 0s;
}

.blob-2 {
  width: 500px;
  height: 500px;
  background: var(--color-secondary);
  bottom: -20%;
  right: -10%;
  animation-delay: -5s;
}

.blob-3 {
  width: 300px;
  height: 300px;
  background: var(--color-accent);
  top: 40%;
  left: 30%;
  animation-duration: 25s;
  opacity: 0.2;
}

@keyframes float {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(50px, -20px) scale(1.1); }
  100% { transform: translate(-30px, 40px) scale(0.9); }
}

/* App Container */
#app-container {
  position: relative;
  width: 100%;
  height: 100vh;
}

.screen {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transition: opacity var(--transition-smooth), visibility var(--transition-smooth);
}

.hidden {
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

/* Glass Card Premium Core Component */
.glass-card {
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1.5px solid var(--glass-border);
  border-top: 1.5px solid var(--glass-border-light);
  box-shadow: var(--glass-shadow), inset 0 1px 1px rgba(255, 255, 255, 0.05);
  border-radius: 28px;
  transition: transform 0.3s, box-shadow 0.3s;
}

/* Splash Screen Specifics */
.splash-content {
  padding: 40px 60px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.logo-container {
  width: 80px;
  height: 80px;
  border-radius: 20px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  box-shadow: 0 10px 25px rgba(var(--hue-primary), 80%, 50%, 0.4);
}

.logo-icon {
  font-size: 48px;
  color: white;
}

.brand-title {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 8px;
  background: linear-gradient(to right, #fff, var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-subtitle {
  font-size: 14px;
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 40px;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.loading-bar-container {
  width: 200px;
  height: 4px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 12px;
}

.loading-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  transition: width 0.3s ease;
  animation: load 2s infinite cubic-bezier(0.2, 0.8, 0.2, 1);
}

@keyframes load {
  0% { transform: translateX(-100%); width: 50%; }
  100% { transform: translateX(200%); width: 50%; }
}

.status-text {
  font-size: 13px;
  color: var(--text-muted);
}

/* Login Screen Specifics */
.login-content {
  width: 90%;
  max-width: 420px;
  padding: 48px 40px;
  text-align: center;
}

.login-header i.small {
  font-size: 36px;
  color: var(--color-primary);
  margin-bottom: 16px;
  text-shadow: 0 0 20px rgba(var(--hue-primary), 80%, 50%, 0.5);
}

.login-header h2 {
  font-size: 28px;
  font-weight: 600;
  margin-bottom: 12px;
}

.login-header h2 span {
  background: linear-gradient(to right, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 700;
}

.login-header p {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.6;
  margin-bottom: 48px;
}

/* Google Button */
.btn {
  border: none;
  background: transparent;
  cursor: pointer;
  font-family: inherit;
  outline: none;
  position: relative;
  overflow: hidden;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-premium {
  width: 100%;
  padding: 16px 24px;
  border-radius: 16px;
  font-size: 16px;
  font-weight: 600;
  transition: all var(--transition-smooth);
}

.btn-google {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
}

.btn-google:hover {
  background: rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
  border-color: rgba(255, 255, 255, 0.2);
}

.btn-google:active {
  transform: translateY(0);
}

.google-logo {
  margin-right: 12px;
}

.btn-sparkle {
  position: absolute;
  top: 0; left: -100%; width: 50%; height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
  transform: skewX(-20deg);
  transition: 0.5s;
}

.btn-google:hover .btn-sparkle {
  left: 200%;
  transition: left 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

.login-footer {
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--glass-border);
}

.login-footer p {
  font-size: 12px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.login-footer i {
  font-size: 16px;
  color: var(--color-primary);
}

.login-footer strong {
  color: var(--text-secondary);
  font-weight: 500;
}

/* Utilities */
.animate-slide-up {
  animation: slideUp 0.8s var(--transition-bounce) both;
}

@keyframes slideUp {
  0% { transform: translateY(40px); opacity: 0; }
  100% { transform: translateY(0); opacity: 1; }
}