:root {
  --bg-primary: #090d16;
  --bg-card: rgba(19, 27, 46, 0.7);
  --bg-card-hover: rgba(28, 39, 66, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-active: rgba(56, 189, 248, 0.4);
  --accent-cyan: #38bdf8;
  --accent-blue: #3b82f6;
  --accent-purple: #8b5cf6;
  --accent-green: #10b981;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --radius-lg: 22px;
  --radius-md: 14px;
  --radius-sm: 8px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-main);
  min-height: 100vh;
  line-height: 1.5;
  background-image: 
    radial-gradient(circle at 10% 20%, rgba(56, 189, 248, 0.08) 0%, transparent 45%),
    radial-gradient(circle at 90% 80%, rgba(139, 92, 246, 0.08) 0%, transparent 45%);
  background-attachment: fixed;
  overflow-x: hidden;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

/* Header */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 22px;
  background: var(--bg-card);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  margin-bottom: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  box-shadow: 0 0 16px rgba(56, 189, 248, 0.3);
}

.brand h1 {
  font-size: 1.35rem;
  font-weight: 700;
  background: linear-gradient(135deg, #ffffff 40%, var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.device-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Status Card */
.connection-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  border-radius: var(--radius-md);
  margin-bottom: 24px;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

.connection-bar.connected {
  background: rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.3);
}

.conn-status {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  font-weight: 500;
}

.conn-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #94a3b8;
}

.connection-bar.connected .conn-dot {
  background: #34d399;
  box-shadow: 0 0 10px #34d399;
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(0.85); }
}

/* Main Grid */
.grid-main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-bottom: 24px;
}

@media (max-width: 768px) {
  .grid-main {
    grid-template-columns: 1fr;
  }
}

.card {
  background: var(--bg-card);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: 0 6px 30px rgba(0, 0, 0, 0.25);
}

.card-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}

.card-title h2 {
  font-size: 1.1rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* QR & Pair Section */
.qr-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 16px;
}

.qr-box {
  background: #ffffff;
  padding: 12px;
  border-radius: 16px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
  width: 180px;
  height: 180px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.qr-box img {
  width: 100%;
  height: 100%;
  display: block;
  border-radius: 6px;
}

.room-pill {
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  padding: 8px 16px;
  border-radius: 30px;
  font-family: monospace;
  font-size: 0.95rem;
  color: var(--accent-cyan);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.room-pill:hover {
  background: rgba(56, 189, 248, 0.18);
  border-color: var(--accent-cyan);
}

/* Dropzone & Transfer Area */
.dropzone {
  border: 2px dashed rgba(56, 189, 248, 0.25);
  border-radius: var(--radius-lg);
  padding: 32px 18px;
  text-align: center;
  background: rgba(15, 23, 42, 0.4);
  cursor: pointer;
  transition: all 0.25s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 240px;
}

.dropzone:hover, .dropzone.dragover {
  border-color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.06);
  transform: scale(1.01);
}

.dropzone.disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

/* Radar Animation */
.radar-animation {
  position: relative;
  width: 80px;
  height: 80px;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.radar-wave {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  border: 2px solid var(--accent-cyan);
  opacity: 0.6;
  animation: radar-ping 2.5s cubic-bezier(0, 0.2, 0.8, 1) infinite;
}

.radar-wave:nth-child(2) {
  animation-delay: 0.8s;
}

.radar-wave:nth-child(3) {
  animation-delay: 1.6s;
}

@keyframes radar-ping {
  0% { transform: scale(0.4); opacity: 0.8; }
  100% { transform: scale(1.6); opacity: 0; }
}

.radar-center {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  color: white;
  z-index: 2;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.4);
}

.dropzone.connected-active .radar-center {
  background: linear-gradient(135deg, #10b981, #059669);
  box-shadow: 0 0 24px rgba(16, 185, 129, 0.5);
}

.lossless-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 14px;
  padding: 4px 12px;
  background: rgba(139, 92, 246, 0.15);
  border: 1px solid rgba(139, 92, 246, 0.3);
  border-radius: 20px;
  font-size: 0.75rem;
  color: #c084fc;
  font-weight: 600;
}

/* Progress Section */
.progress-card {
  display: none;
  margin-top: 18px;
  padding: 16px;
  background: rgba(255, 255, 255, 0.03);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.progress-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  margin-bottom: 8px;
}

.progress-bg {
  width: 100%;
  height: 8px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue));
  transition: width 0.1s linear;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: 0.88rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, #0284c7, #2563eb);
  color: white;
  box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #0369a1, #1d4ed8);
  transform: translateY(-1px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* File Activity List */
.file-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 14px;
  max-height: 380px;
  overflow-y: auto;
}

.file-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: rgba(15, 23, 42, 0.5);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  animation: slide-in 0.25s ease-out;
}

@keyframes slide-in {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

.file-left {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.file-icon {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent-cyan);
  flex-shrink: 0;
}

.file-name {
  font-size: 0.9rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 320px;
}

.file-subtext {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.empty-state {
  text-align: center;
  padding: 36px 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid var(--accent-cyan);
  padding: 10px 22px;
  border-radius: 30px;
  color: white;
  font-size: 0.88rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(8px);
  transition: transform 0.3s ease;
  z-index: 1000;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
}