* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
 
html {
  user-select: none;
  -moz-user-select: none;
  -webkit-user-select: none;
}
 
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background: #0f0f0f;
  color: #fff;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}
 
.container {
  max-width: 420px;
}
 
.qr-card {
  background: #2a2a2a;
  border-radius: 24px;
  padding: 32px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  margin-bottom: 24px;
}
 
.qr-wrapper {
  background: #fff;
  border-radius: 20px;
  padding: 24px;
  position: relative;
  overflow: hidden;
}
 
.qr-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  border-radius: 20px;
  transition: all 0.3s ease;
}
 
.bg-1 { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
.bg-2 { background: linear-gradient(135deg, #89f7fe 0%, #66a6ff 100%); }
.bg-3 { background: linear-gradient(135deg, #a8edea 0%, #fed6e3 100%); }
.bg-4 { background: linear-gradient(135deg, #84fab0 0%, #8fd3f4 100%); }
.bg-5 { background: linear-gradient(135deg, #fbc2eb 0%, #a6c1ee 100%); }
.bg-6 { background: linear-gradient(135deg, #fdcbf1 0%, #e6dee9 100%); }
.bg-7 { background: linear-gradient(135deg, #f6d365 0%, #fda085 100%); }
.bg-8 { background: linear-gradient(135deg, #a1c4fd 0%, #c2e9fb 100%); }
.bg-9 { background: linear-gradient(135deg, #ff9a9e 0%, #fecfef 100%); }
.bg-10 { background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%); }
.bg-11 { background: linear-gradient(135deg, #ff6e7f 0%, #bfe9ff 100%); }
.bg-12 { background: linear-gradient(135deg, #e0c3fc 0%, #8ec5fc 100%); }
.bg-13 { background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%); }
.bg-14 { background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%); }
.bg-15 { background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%); }
.bg-16 { background: linear-gradient(135deg, #fa709a 0%, #fee140 100%); }
.bg-17 { background: linear-gradient(135deg, #30cfd0 0%, #330867 100%); }
.bg-18 { background: linear-gradient(135deg, #a8ff78 0%, #78ffd6 100%); }
.bg-19 { background: linear-gradient(135deg, #ff0844 0%, #ffb199 100%); }
.bg-20 { background: linear-gradient(135deg, #13547a 0%, #80d0c7 100%); }
 
.qr-content {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}
 
.avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  overflow: hidden;
  position: relative;
}
 
.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
 
.avatar-emoji {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
}
 
#qrcode {
  background: #fff;
  padding: 16px;
  border-radius: 16px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}
 
#qrcode canvas {
  display: block !important;
  border-radius: 8px;
}
 
.username {
  font-size: 20px;
  font-weight: 600;
  color: #fff;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}
 
.input-group {
  margin-bottom: 16px;
}
 
label {
  display: block;
  margin-bottom: 8px;
  font-size: 14px;
  color: #aaa;
}
 
input[type="text"] {
  width: 100%;
  padding: 12px 16px;
  background: #1a1a1a;
  border: 2px solid #3a3a3a;
  border-radius: 12px;
  color: #fff;
  font-size: 15px;
  transition: border-color 0.3s;
}
 
input[type="text"]:focus {
  outline: none;
  border-color: #667eea;
}
 
.backgrounds {
  margin-top: 8px;
}
 
.bg-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}
 
.bg-option {
  width: 100%;
  aspect-ratio: 1;
  border-radius: 12px;
  cursor: pointer;
  border: 3px solid transparent;
  transition: all 0.3s;
  position: relative;
  overflow: hidden;
}
 
.bg-option::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 24px;
  height: 24px;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="white"><path d="M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41L9 16.17z"/></svg>')
    center/contain no-repeat;
  opacity: 0;
  transition: opacity 0.3s;
}
 
.bg-option.active {
  border-color: #fff;
}
 
.bg-option.active::before {
  opacity: 1;
}
 
.bg-option:hover {
  transform: scale(1.05);
}
 
.btn {
  width: 100%;
  padding: 14px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  border: none;
  border-radius: 12px;
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  margin-top: 8px;
}
 
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}
 
.btn:active {
  transform: translateY(0);
}
 
.file-input-wrapper {
  position: relative;
  overflow: hidden;
  display: inline-block;
  width: 100%;
}
 
.file-input-wrapper input[type="file"] {
  position: absolute;
  left: -9999px;
}
 
.file-input-label {
  display: block;
  padding: 12px 16px;
  background: #1a1a1a;
  border: 2px dashed #3a3a3a;
  border-radius: 12px;
  color: #aaa;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  font-size: 14px;
}
 
.file-input-label:hover {
  border-color: #667eea;
  background: #252525;
}
 
.file-input-label.has-file {
  border-color: #667eea;
  color: #667eea;
}
 
.avatar-mode {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}
 
.mode-btn {
  flex: 1;
  padding: 8px;
  background: #1a1a1a;
  border: 2px solid #3a3a3a;
  border-radius: 8px;
  color: #aaa;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.3s;
}
 
.mode-btn.active {
  background: #667eea;
  border-color: #667eea;
  color: #fff;
}
 
.mode-btn:hover:not(.active) {
  border-color: #667eea;
}
 
.controls {
  background: #2a2a2a;
  border-radius: 24px;
  padding: 24px;
}
 
h3 {
  margin-bottom: 16px;
  font-size: 16px;
  color: #fff;
}
 
/* — adaptive — */
 
@media screen and (max-width: 380px) {
  .container {
    width: 100%;
  }
 
  .qr-card {
    padding: 20px;
  }
 
  .controls {
    padding: 16px;
  }
 
  .bg-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
  }
}
 
@media screen and (max-width: 320px) {
  body {
    padding: 12px;
  }
 
  .qr-card {
    padding: 16px;
    border-radius: 16px;
  }
 
  .controls {
    padding: 12px;
    border-radius: 16px;
  }
 
  .qr-wrapper {
    padding: 16px;
  }
 
  .avatar {
    width: 64px;
    height: 64px;
    font-size: 28px;
  }
 
  #qrcode {
    padding: 10px;
  }
 
  .username {
    font-size: 16px;
  }
 
  input[type="text"] {
    padding: 10px 12px;
    font-size: 14px;
  }
 
  .btn {
    padding: 12px;
    font-size: 14px;
  }
 
  .mode-btn {
    padding: 6px;
    font-size: 12px;
  }
 
  .bg-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
  }
}
 
@media screen and (max-width: 280px) {
  body {
    padding: 8px;
  }

  .qr-background {
    border-radius: 10px;
  }
  
  .qr-card {
    padding: 12px;
    border-radius: 12px;
    margin-bottom: 12px;
  }
 
  .controls {
    padding: 10px;
    border-radius: 12px;
  }
 
  .qr-wrapper {
    padding: 12px;
    border-radius: 12px;
  }
 
  .avatar {
    width: 52px;
    height: 52px;
    font-size: 22px;
  }
 
  #qrcode {
    padding: 8px;
    border-radius: 10px;
  }
 
  .username {
    font-size: 14px;
  }
 
  input[type="text"] {
    padding: 8px 10px;
    font-size: 13px;
    border-radius: 8px;
  }
 
  .input-group {
    margin-bottom: 10px;
  }
 
  label {
    font-size: 12px;
  }
 
  .btn {
    padding: 10px;
    font-size: 13px;
    border-radius: 8px;
  }
 
  .mode-btn {
    padding: 5px 4px;
    font-size: 11px;
    border-radius: 6px;
  }
 
  .bg-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 4px;
  }
 
  .bg-option {
    border-radius: 6px;
    border-width: 2px;
  }
 
  h3 {
    font-size: 13px;
    margin-bottom: 10px;
  }
 
  .file-input-label {
    padding: 8px 10px;
    font-size: 12px;
    border-radius: 8px;
  }
 
  .avatar-mode {
    gap: 6px;
    margin-bottom: 8px;
  }
}