:root{
  --wa-dark-green: #075E54;
  --wa-teal-green: #128C7E;
  --wa-light-green: #25D366;
  --wa-bubble-out: #DCF8C6;
  --wa-bubble-in: #FFFFFF;
  --wa-bg: #ECE5DD;
  --wa-text-dark: #111B21;
  --wa-text-muted: #667781;
  --wa-danger: #FDECEA;
  --wa-danger-text: #B3261E;
}

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

body{
  font-family: 'Segoe UI', Helvetica, Arial, sans-serif;
  background: #0b141a;
  display: flex;
  justify-content: center;
  min-height: 100vh;
}

.app{
  width: 100%;
  max-width: 480px;
  min-height: 100vh;
  background: var(--wa-bg);
  display: flex;
  flex-direction: column;
  box-shadow: 0 0 40px rgba(0,0,0,0.4);
  position: relative;
}

/* Header */
.app-header{
  background: var(--wa-dark-green);
  color: white;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  position: sticky;
  top: 0;
  z-index: 10;
}

.avatar{
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--wa-teal-green);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.header-info h1{
  font-size: 17px;
  font-weight: 600;
}

.status-text{
  font-size: 12px;
  opacity: 0.85;
}

.changelog-btn{
  background: rgba(255,255,255,0.15);
  border: none;
  color: white;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s ease;
  flex-shrink: 0;
}

#musicBtn{
  margin-left: auto;
}

.changelog-btn:hover{
  background: rgba(255,255,255,0.28);
}

/* Panel changelog */
.changelog-overlay{
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.45);
  z-index: 100;
  justify-content: center;
  align-items: flex-start;
}

.changelog-overlay.open{
  display: flex;
}

.changelog-panel{
  width: 100%;
  max-width: 480px;
  background: var(--wa-bg);
  margin-top: 0;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  border-radius: 0 0 12px 12px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.35);
  animation: slideDown 0.2s ease;
}

@keyframes slideDown{
  from{ transform: translateY(-12px); opacity: 0; }
  to{ transform: translateY(0); opacity: 1; }
}

.changelog-header{
  background: var(--wa-dark-green);
  color: white;
  padding: 14px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 600;
  font-size: 15px;
}

.changelog-close{
  background: none;
  border: none;
  color: white;
  font-size: 16px;
  cursor: pointer;
  width: 28px;
  height: 28px;
  border-radius: 50%;
}

.changelog-close:hover{
  background: rgba(255,255,255,0.15);
}

.changelog-body{
  overflow-y: auto;
  padding: 14px 16px;
}

.changelog-entry{
  background: white;
  border-radius: 8px;
  padding: 10px 12px;
  margin-bottom: 10px;
  box-shadow: 0 1px 1px rgba(0,0,0,0.08);
}

.changelog-version{
  font-weight: 700;
  color: var(--wa-teal-green);
  font-size: 13.5px;
  margin-bottom: 4px;
}

.changelog-date{
  font-weight: 400;
  color: var(--wa-text-muted);
  font-size: 11.5px;
  margin-left: 6px;
}

.changelog-entry p{
  font-size: 13px;
  color: var(--wa-text-dark);
  line-height: 1.4;
}

.changelog-entry code{
  background: #f0f0f0;
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 12px;
  color: #d63384;
}

/* Chat area */
.chat-area{
  flex: 1;
  padding: 16px 12px 100px 12px;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(0,0,0,0.02) 1px, transparent 1px);
  background-size: 20px 20px;
  overflow-y: auto;
}

.date-chip{
  text-align: center;
  background: #E1F3FB;
  color: #54656F;
  font-size: 12px;
  padding: 6px 12px;
  border-radius: 8px;
  width: fit-content;
  margin: 0 auto 16px auto;
  box-shadow: 0 1px 1px rgba(0,0,0,0.08);
}

.bubble{
  background: var(--wa-bubble-in);
  border-radius: 8px;
  padding: 10px 12px 18px 12px;
  margin-bottom: 10px;
  max-width: 88%;
  position: relative;
  box-shadow: 0 1px 1px rgba(0,0,0,0.1);
  font-size: 14.5px;
  line-height: 1.4;
  color: var(--wa-text-dark);
  word-wrap: break-word;
  overflow-wrap: anywhere;
}

.bubble-left{
  margin-right: auto;
  border-top-left-radius: 0;
}

.bubble p code{
  background: #f0f0f0;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 12.5px;
  color: #d63384;
  display: inline-block;
  max-width: 100%;
  word-break: break-all;
  overflow-wrap: anywhere;
  white-space: normal;
  line-height: 1.4;
  vertical-align: top;
}

.bubble .time{
  position: absolute;
  bottom: 6px;
  right: 10px;
  font-size: 11px;
  color: var(--wa-text-muted);
}

.bubble.warn{
  background: var(--wa-danger);
  color: var(--wa-danger-text);
}

/* Upload card */
.upload-card{
  max-width: 100%;
}

.dropzone{
  border: 2px dashed var(--wa-teal-green);
  border-radius: 10px;
  padding: 24px 12px;
  text-align: center;
  margin: 10px 0;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease;
  background: #FAFFFC;
}

.dropzone.dragover{
  background: #E7FCEF;
  border-color: var(--wa-light-green);
}

.drop-icon{
  font-size: 32px;
  margin-bottom: 6px;
}

.dropzone p{
  font-size: 13.5px;
  color: var(--wa-text-muted);
}

.file-selected{
  color: var(--wa-teal-green);
  font-weight: 600;
}

.checkbox-row{
  display: flex;
  align-items: flex-start;
  gap: 8px;
  font-size: 13px;
  color: var(--wa-text-muted);
  margin: 10px 0 14px 0;
  cursor: pointer;
}

.checkbox-row input{
  margin-top: 3px;
  accent-color: var(--wa-teal-green);
}

.info-fix-list{
  background: #F7F7F7;
  border-radius: 8px;
  padding: 10px 12px;
  margin: 10px 0 14px 0;
}

.info-fix-list ul{
  list-style: disc;
}

.info-fix-list code{
  background: #eee;
  padding: 1px 5px;
  border-radius: 4px;
  color: #d63384;
}

.btn-main{
  width: 100%;
  background: var(--wa-teal-green);
  color: white;
  border: none;
  padding: 12px;
  border-radius: 8px;
  font-size: 14.5px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease, opacity 0.2s ease;
}

.btn-main:disabled{
  background: #9fbfba;
  cursor: not-allowed;
}

.btn-main:not(:disabled):hover{
  background: var(--wa-dark-green);
}

/* Result bubbles */
.result-bubble{
  background: var(--wa-bubble-out);
  margin-left: auto;
  border-top-right-radius: 0;
  border-top-left-radius: 8px;
  max-width: 88%;
}

.result-bubble.error{
  background: var(--wa-danger);
  color: var(--wa-danger-text);
}

.download-btn{
  display: inline-block;
  margin-top: 10px;
  background: var(--wa-light-green);
  color: white;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 13.5px;
}

/* Footer */
.app-footer{
  position: sticky;
  bottom: 0;
  background: #F0F0F0;
  padding: 10px 14px;
  border-top: 1px solid #ddd;
}

.fake-input{
  background: white;
  border-radius: 20px;
  padding: 10px 16px;
  font-size: 12.5px;
  color: var(--wa-text-muted);
  text-align: center;
}

.credit-footer{
  text-align: center;
  font-size: 11px;
  color: #8a9299;
  margin-top: 8px;
  letter-spacing: 0.2px;
}

@media (max-width: 500px){
  .app{
    max-width: 100%;
  }

  .chat-area{
    padding: 12px 8px 100px 8px;
  }

  .bubble{
    max-width: 94%;
    font-size: 14px;
    padding: 9px 10px 16px 10px;
  }

  .bubble p code{
    font-size: 11.5px;
  }

  .header-info h1{
    font-size: 16px;
  }
}