/* =============================================
   ATLAS WEB — Design System
   Premium dark-mode P2P file transfer UI
   ============================================= */

/* --- CSS Custom Properties (Design Tokens) --- */
:root {
  /* Color palette */
  --color-bg-primary: #0a0b1a;
  --color-bg-secondary: #111227;
  --color-bg-card: rgba(255, 255, 255, 0.04);
  --color-bg-glass: rgba(255, 255, 255, 0.06);
  --color-bg-glass-hover: rgba(255, 255, 255, 0.10);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
  --gradient-accent: linear-gradient(135deg, #7c3aed 0%, #ec4899 100%);
  --gradient-glow: linear-gradient(135deg, rgba(99, 102, 241, 0.3) 0%, rgba(168, 85, 247, 0.3) 100%);

  /* Text */
  --color-text-primary: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-text-accent: #a78bfa;

  /* Interactive states */
  --color-accent: #7c3aed;
  --color-accent-hover: #8b5cf6;
  --color-accent-glow: rgba(124, 58, 237, 0.35);
  --color-success: #22c55e;
  --color-success-glow: rgba(34, 197, 94, 0.25);
  --color-warning: #eab308;
  --color-error: #ef4444;
  --color-info: #3b82f6;

  /* Status dots */
  --color-connected: #22c55e;
  --color-disconnected: #64748b;
  --color-connecting: #eab308;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 48px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px rgba(124, 58, 237, 0.15);
  --shadow-glow-active: 0 0 60px rgba(124, 58, 237, 0.25);

  /* Glassmorphism */
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-blur: 20px;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 3rem;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Layout */
  --max-width: 600px;
  --header-height: 64px;
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--color-bg-primary);
  color: var(--color-text-primary);
  min-height: 100vh;
  min-height: 100dvh;
  overflow-x: hidden;
  line-height: 1.6;
  position: relative;
}

/* Dynamic background */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 0% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 100% 80%, rgba(168, 85, 247, 0.06) 0%, transparent 60%),
    radial-gradient(ellipse 50% 40% at 50% 50%, rgba(124, 58, 237, 0.03) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

#app {
  position: relative;
  z-index: 1;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

a {
  color: var(--color-text-accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}
a:hover {
  color: var(--color-accent-hover);
}

code {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
}

/* --- App Shell --- */
.app {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  min-height: 100dvh;
  padding: var(--space-4);
}

.screen {
  display: none;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: var(--max-width);
  padding: var(--space-4) 0;
  animation: fadeSlideUp var(--transition-slow) ease-out;
}
.screen.active {
  display: flex;
}

/* --- Landing Screen --- */
.landing-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - var(--space-8) * 2);
  min-height: calc(100dvh - var(--space-8) * 2);
  gap: var(--space-10);
  text-align: center;
}

.logo-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.logo-icon {
  margin-bottom: var(--space-2);
  animation: float 6s ease-in-out infinite;
}

.logo-text {
  font-size: var(--font-size-4xl);
  font-weight: 800;
  letter-spacing: -0.03em;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.logo-accent {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.tagline {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  line-height: 1.5;
  max-width: 360px;
}

/* --- Action Cards --- */
.action-cards {
  display: flex;
  gap: var(--space-4);
  width: 100%;
  max-width: 480px;
}

.action-card {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-6) var(--space-4);
  background: var(--color-bg-glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--color-text-primary);
  position: relative;
  overflow: hidden;
}

.action-card::before {
  content: '';
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.action-card.primary::before {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(168, 85, 247, 0.1));
}
.action-card.secondary::before {
  background: linear-gradient(135deg, rgba(124, 58, 237, 0.08), rgba(236, 72, 153, 0.08));
}

.action-card:hover {
  transform: translateY(-2px);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-glow);
}
.action-card:hover::before {
  opacity: 1;
}
.action-card:active {
  transform: translateY(0);
}

.card-icon {
  position: relative;
  z-index: 1;
  color: var(--color-text-accent);
  opacity: 0.9;
}

.card-title {
  position: relative;
  z-index: 1;
  font-size: var(--font-size-lg);
  font-weight: 600;
}

.card-desc {
  position: relative;
  z-index: 1;
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

/* --- Join Input --- */
.join-input-group {
  display: flex;
  gap: var(--space-3);
  width: 100%;
  max-width: 480px;
}

.input-glass {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  color: var(--color-text-primary);
  font-size: var(--font-size-sm);
  font-family: var(--font-family);
  outline: none;
  transition: all var(--transition-base);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}
.input-glass::placeholder {
  color: var(--color-text-muted);
}
.input-glass:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.btn-glass {
  padding: var(--space-3) var(--space-6);
  background: var(--gradient-primary);
  border: none;
  border-radius: var(--radius-lg);
  color: white;
  font-size: var(--font-size-sm);
  font-weight: 600;
  font-family: var(--font-family);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}
.btn-glass:hover {
  transform: translateY(-1px);
  box-shadow: 0 0 30px rgba(124, 58, 237, 0.4);
}
.btn-glass:active {
  transform: translateY(0);
}

/* --- Room Screen Header --- */
.room-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--space-2) 0;
  margin-bottom: var(--space-6);
}

.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--color-bg-glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}
.btn-icon:hover {
  background: var(--color-bg-glass-hover);
  color: var(--color-text-primary);
}

.room-status {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  transition: all var(--transition-base);
}
.status-dot.connected {
  background: var(--color-connected);
  box-shadow: 0 0 8px var(--color-success-glow);
}
.status-dot.disconnected {
  background: var(--color-disconnected);
}
.status-dot.connecting {
  background: var(--color-connecting);
  animation: pulse-dot 1.5s ease-in-out infinite;
}

/* --- Room Code Display --- */
.room-body {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.code-display {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
}

.code-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.code-value-container {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-5);
  background: var(--color-bg-glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.code-value {
  font-size: var(--font-size-xl);
  font-weight: 700;
  letter-spacing: 0.15em;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  user-select: all;
}

.btn-icon-sm {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: var(--color-bg-glass-hover);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all var(--transition-fast);
}
.btn-icon-sm:hover {
  background: var(--color-accent-glow);
  color: var(--color-text-accent);
}

/* --- QR Code --- */
.qrcode-container {
  display: flex;
  justify-content: center;
  padding: var(--space-4);
}

#qrcode {
  padding: var(--space-4);
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}
#qrcode img {
  display: block;
}

/* --- Response Paste Section (Serverless Cut-and-Choose) --- */
.response-input-section {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-5);
  background: var(--color-bg-glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  margin: 0 0 var(--space-2) 0;
  animation: fadeSlideUp var(--transition-slow) ease-out;
}

.response-input-section.hidden {
  display: none;
}

.response-hint {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin: 0 0 var(--space-2) 0;
  line-height: 1.5;
}

.response-input-row {
  display: flex;
  gap: var(--space-3);
  align-items: center;
}

.response-input {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-primary);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  color: var(--color-text-primary);
  font-size: var(--font-size-sm);
  font-family: var(--font-mono);
  outline: none;
  transition: all var(--transition-base);
}
.response-input::placeholder {
  color: var(--color-text-muted);
  font-family: var(--font-family);
  font-size: var(--font-size-xs);
}
.response-input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.btn-connect {
  flex-shrink: 0;
  background: var(--gradient-accent);
}
.btn-connect:hover {
  box-shadow: 0 0 30px rgba(236, 72, 153, 0.4);
}

/* --- Transfer Zone --- */
.transfer-zone {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-12) var(--space-6);
  background: var(--color-bg-glass);
  border: 2px dashed var(--glass-border);
  border-radius: var(--radius-xl);
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--color-text-muted);
  position: relative;
}

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--color-accent);
  background: rgba(124, 58, 237, 0.06);
  box-shadow: var(--shadow-glow);
  color: var(--color-text-secondary);
}

.drop-zone.drag-over svg {
  color: var(--color-text-accent);
}

.drop-text {
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-text-secondary);
}

.drop-sub {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.file-input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

.transfer-actions {
  display: flex;
  gap: var(--space-3);
  justify-content: center;
}

/* --- Transfer Queue --- */
.transfer-queue {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.transfer-queue.hidden {
  display: none;
}

.transfer-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.transfer-icon {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background: var(--color-bg-glass-hover);
}

.transfer-info {
  flex: 1;
  min-width: 0;
}

.transfer-name {
  font-size: var(--font-size-sm);
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.transfer-size {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.transfer-progress {
  width: 100%;
  height: 4px;
  background: var(--color-bg-glass-hover);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-top: var(--space-2);
}

.transfer-progress-bar {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
  width: 0%;
}

.transfer-progress-text {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  white-space: nowrap;
}

.transfer-status {
  font-size: var(--font-size-xs);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-weight: 500;
}
.transfer-status.pending {
  color: var(--color-warning);
  background: rgba(234, 179, 8, 0.1);
}
.transfer-status.sending {
  color: var(--color-info);
  background: rgba(59, 130, 246, 0.1);
}
.transfer-status.complete {
  color: var(--color-success);
  background: rgba(34, 197, 94, 0.1);
}
.transfer-status.error {
  color: var(--color-error);
  background: rgba(239, 68, 68, 0.1);
}

/* --- Receiver Screen --- */
.receive-area {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 300px;
}

.waiting-animation {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  color: var(--color-text-muted);
  position: relative;
}

.pulse-ring {
  position: absolute;
  width: 100px;
  height: 100px;
  border: 2px solid var(--color-accent);
  border-radius: 50%;
  animation: pulse-ring 2s ease-out infinite;
  opacity: 0;
}

.waiting-text {
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-text-secondary);
}

.receive-progress {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.receive-progress.hidden {
  display: none;
}

/* --- Toast Notifications --- */
.toast-container {
  position: fixed;
  bottom: var(--space-6);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  z-index: 100;
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-5);
  background: var(--color-bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  box-shadow: var(--shadow-lg);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  pointer-events: auto;
  animation: toastIn var(--transition-bounce) ease-out;
  max-width: 400px;
}

.toast.removing {
  animation: toastOut var(--transition-base) ease-in forwards;
}

.toast.success { border-left: 3px solid var(--color-success); }
.toast.error { border-left: 3px solid var(--color-error); }
.toast.info { border-left: 3px solid var(--color-info); }
.toast.warning { border-left: 3px solid var(--color-warning); }

/* --- Animations --- */
@keyframes fadeSlideUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

@keyframes pulse-dot {
  0%, 100% { opacity: 0.4; }
  50% { opacity: 1; }
}

@keyframes pulse-ring {
  0% { transform: scale(0.5); opacity: 0.5; }
  100% { transform: scale(1.3); opacity: 0; }
}

@keyframes toastIn {
  from {
    opacity: 0;
    transform: translateY(16px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes toastOut {
  from {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
  to {
    opacity: 0;
    transform: translateY(-8px) scale(0.95);
  }
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--color-bg-glass-hover);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-muted);
}

/* --- Responsive --- */
@media (max-width: 480px) {
  .app {
    padding: var(--space-3);
  }

  .action-cards {
    flex-direction: column;
  }

  .logo-text {
    font-size: var(--font-size-3xl);
  }

  .code-value {
    font-size: var(--font-size-lg);
  }

  .drop-zone {
    padding: var(--space-8) var(--space-4);
  }
}

@media (min-width: 768px) {
  .drop-zone {
    padding: var(--space-16) var(--space-8);
  }
}

/* --- Utility Classes --- */
.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}