/* =======================================================
   4U DROP — Ultra-Responsive Mobile Design System v17.0
   ======================================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Outfit:wght@500;600;700;800&display=swap');

:root {
  --bg-primary: #07090e;
  --bg-surface: #0f1523;
  --bg-surface-elevated: #161e31;
  --bg-glass: rgba(15, 21, 35, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(0, 242, 254, 0.3);

  --accent-cyan: #00f2fe;
  --accent-blue: #4facfe;
  --accent-purple: #7928ca;
  --accent-magenta: #ff0080;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-full: 9999px;

  --shadow-glow: 0 0 25px rgba(0, 242, 254, 0.15);
  --shadow-purple-glow: 0 0 25px rgba(121, 40, 202, 0.2);
  --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.5);

  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

*, *::before, *::after {
  box-sizing: border-box !important;
  margin: 0;
  padding: 0;
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  -webkit-font-smoothing: antialiased;
}

html, body {
  width: 100% !important;
  max-width: 100% !important;
  overflow-x: hidden !important;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
}

/* Ambient Background Lighting */
body::before {
  content: '';
  position: fixed;
  top: -10%;
  left: 20%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(0, 242, 254, 0.08) 0%, rgba(0,0,0,0) 70%);
  pointer-events: none;
  z-index: 0;
}

body::after {
  content: '';
  position: fixed;
  bottom: -10%;
  right: 15%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(121, 40, 202, 0.08) 0%, rgba(0,0,0,0) 70%);
  pointer-events: none;
  z-index: 0;
}

/* Header Navbar */
.app-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(7, 9, 14, 0.95);
  border-bottom: 1px solid var(--border-color);
  padding: 0.85rem 1.25rem;
  width: 100%;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  text-decoration: none;
  color: var(--text-primary);
  flex-shrink: 0;
}

.brand-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  box-shadow: var(--shadow-glow);
}

.brand-text span {
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-shrink: 0;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.8rem;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.25);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-emerald);
  white-space: nowrap;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-emerald);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-emerald);
  animation: pulse-ring 1.8s infinite;
  flex-shrink: 0;
}

@keyframes pulse-ring {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

/* Main Workspace Grid */
.main-wrapper {
  max-width: 1200px;
  margin: 1.5rem auto;
  padding: 0 1.25rem;
  width: 100%;
  z-index: 10;
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 1.5rem;
}

.left-column, .right-column {
  min-width: 0;
  width: 100%;
}

/* Cards & Panels */
.glass-panel {
  background: var(--bg-glass);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  transition: border-color var(--transition-normal);
  width: 100%;
  max-width: 100%;
  overflow: hidden;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.panel-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  word-break: break-word;
  white-space: normal;
}

/* Drop Zone Area */
.drop-zone {
  border: 2px dashed rgba(0, 242, 254, 0.3);
  background: rgba(0, 242, 254, 0.02);
  border-radius: var(--radius-lg);
  padding: 2.5rem 1.25rem;
  text-align: center;
  cursor: pointer;
  position: relative;
  transition: all var(--transition-normal);
  overflow: hidden;
  width: 100%;
}

.drop-zone:hover, .drop-zone.drag-over {
  border-color: var(--accent-cyan);
  background: rgba(0, 242, 254, 0.06);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

.drop-icon-wrapper {
  width: 60px;
  height: 60px;
  margin: 0 auto 1rem;
  background: linear-gradient(135deg, rgba(0, 242, 254, 0.15), rgba(121, 40, 202, 0.15));
  border: 1px solid rgba(0, 242, 254, 0.3);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-cyan);
  font-size: 1.6rem;
  transition: transform var(--transition-spring);
}

.drop-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  word-break: break-word;
  white-space: normal;
}

.drop-subtitle {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.1rem;
  word-break: break-word;
  white-space: normal;
  line-height: 1.4;
}

.btn-select-file {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  color: #040810;
  font-weight: 700;
  font-size: 0.875rem;
  padding: 0.7rem 1.35rem;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 15px rgba(0, 242, 254, 0.3);
  transition: all var(--transition-normal);
  white-space: nowrap;
}

.btn-select-file:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 22px rgba(0, 242, 254, 0.45);
}

/* Tabs & Controls */
.content-tabs {
  display: flex;
  background: rgba(255, 255, 255, 0.04);
  padding: 0.3rem;
  border-radius: var(--radius-md);
  margin-bottom: 1.25rem;
  border: 1px solid var(--border-color);
  width: 100%;
}

.tab-btn {
  flex: 1;
  padding: 0.55rem 0.75rem;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.825rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  white-space: nowrap;
}

.tab-btn.active {
  background: var(--bg-surface-elevated);
  color: var(--text-primary);
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

/* File Items */
.file-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-height: 400px;
  overflow-y: auto;
  width: 100%;
}

.file-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 0.8rem 1rem;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  width: 100%;
}

.file-info {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  min-width: 0;
  flex: 1;
}

.file-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  color: var(--accent-cyan);
  flex-shrink: 0;
}

.file-meta {
  min-width: 0;
  flex: 1;
}

.file-name {
  font-weight: 600;
  font-size: 0.875rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 220px;
}

.file-details {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

.file-actions {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-shrink: 0;
}

.btn-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-icon:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.1);
}

/* Sidebar Pairing Panel */
.pairing-panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  width: 100%;
}

.qr-box {
  background: #ffffff;
  padding: 0.85rem;
  border-radius: var(--radius-md);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.4);
  margin: 0.85rem 0;
}

.qr-box canvas, .qr-box img {
  display: block;
  width: 170px;
  height: 170px;
}

.pin-code-badge {
  background: rgba(0, 242, 254, 0.08);
  border: 1px solid rgba(0, 242, 254, 0.2);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  font-family: 'Outfit', monospace;
  font-size: 1.3rem;
  font-weight: 800;
  letter-spacing: 0.2em;
  color: var(--accent-cyan);
  margin: 0.6rem 0;
}

/* Manual PIN Input Group */
.manual-pin-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  width: 100%;
  margin-top: 0.5rem;
}

/* Clean Bulletproof List Styling (No double dots) */
ul.instructions-list {
  list-style: none !important;
  list-style-type: none !important;
  padding: 0 !important;
  margin: 1rem 0 0 0 !important;
  text-align: left;
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.5;
  width: 100%;
}

ul.instructions-list li {
  list-style: none !important;
  list-style-type: none !important;
  margin-bottom: 0.4rem;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  word-break: break-word;
  white-space: normal;
}

ul.instructions-list li::before {
  content: none !important;
}

.clipboard-input-wrapper {
  display: flex;
  gap: 0.5rem;
  width: 100%;
}

.clipboard-input {
  flex: 1;
  width: 100%;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.65rem 0.9rem;
  color: var(--text-primary);
  font-size: 0.85rem;
  outline: none;
}

/* Centered Footer */
.app-footer {
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem 0.85rem;
  font-size: 0.775rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  margin-top: auto;
  width: 100%;
}

.app-footer p {
  text-align: center;
  width: 100%;
  margin: 0 auto;
}

/* =======================================================
   STRICT MOBILE FULL-WIDTH OVERRIDES (max-width: 640px)
   ======================================================= */
@media (max-width: 640px) {
  html, body {
    width: 100% !important;
    max-width: 100% !important;
    overflow-x: hidden !important;
    margin: 0 !important;
    padding: 0 !important;
  }

  .app-header {
    padding: 0.5rem 0.6rem !important;
    width: 100% !important;
  }

  .nav-container {
    padding: 0 !important;
    width: 100% !important;
  }

  .brand {
    font-size: 1.05rem !important;
    gap: 0.35rem !important;
  }

  .brand-icon {
    width: 30px !important;
    height: 30px !important;
  }

  .header-actions {
    gap: 0.3rem !important;
  }

  .status-badge {
    padding: 0.25rem 0.5rem !important;
    font-size: 0.7rem !important;
  }

  #pwaInstallBtn {
    padding: 0.25rem 0.5rem !important;
    font-size: 0.7rem !important;
  }

  .main-wrapper {
    display: flex !important;
    flex-direction: column !important;
    margin: 0.5rem 0 !important;
    padding: 0 0.5rem !important;
    gap: 0.85rem !important;
    width: 100% !important;
    max-width: 100% !important;
    box-sizing: border-box !important;
    overflow-x: hidden !important;
  }

  .left-column, .right-column {
    width: 100% !important;
    max-width: 100% !important;
    box-sizing: border-box !important;
  }

  .glass-panel {
    padding: 0.85rem 0.65rem !important;
    border-radius: var(--radius-md) !important;
    width: 100% !important;
    max-width: 100% !important;
    box-sizing: border-box !important;
    overflow: hidden !important;
  }

  .drop-zone {
    padding: 1.25rem 0.4rem !important;
    width: 100% !important;
    box-sizing: border-box !important;
  }

  .drop-icon-wrapper {
    width: 44px !important;
    height: 44px !important;
    font-size: 1.2rem !important;
    margin-bottom: 0.5rem !important;
  }

  .drop-title {
    font-size: 0.95rem !important;
    word-break: break-word !important;
    white-space: normal !important;
  }

  .drop-subtitle {
    font-size: 0.75rem !important;
    margin-bottom: 0.75rem !important;
    word-break: break-word !important;
    white-space: normal !important;
    line-height: 1.35 !important;
  }

  .btn-select-file {
    padding: 0.55rem 0.9rem !important;
    font-size: 0.8rem !important;
    max-width: 100% !important;
  }

  .content-tabs {
    overflow-x: auto !important;
    scrollbar-width: none !important;
    -ms-overflow-style: none !important;
    width: 100% !important;
  }

  .content-tabs::-webkit-scrollbar {
    display: none !important;
  }

  .tab-btn {
    padding: 0.4rem 0.45rem !important;
    font-size: 0.725rem !important;
  }

  .file-item {
    padding: 0.65rem 0.5rem !important;
    width: 100% !important;
    box-sizing: border-box !important;
  }

  .file-name {
    max-width: 100px !important;
    font-size: 0.8rem !important;
  }

  .file-details {
    font-size: 0.685rem !important;
  }

  .manual-pin-group .input-row {
    display: flex !important;
    flex-direction: column !important;
    gap: 0.4rem !important;
    width: 100% !important;
  }

  .manual-pin-group .input-row button {
    width: 100% !important;
  }

  .app-footer {
    padding: 1rem 0.5rem !important;
    font-size: 0.725rem !important;
    text-align: center !important;
    width: 100% !important;
  }

  .app-footer p {
    text-align: center !important;
    width: 100% !important;
    margin: 0 auto !important;
  }
}