:root {
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --bg: #0f172a;
  --card-bg: rgba(30, 41, 59, 0.7);
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --border: rgba(255, 255, 255, 0.1);
  --success: #10b981;
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg);
  background-image: radial-gradient(circle at top right, #1e1b4b, transparent),
                    radial-gradient(circle at bottom left, #1e1b4b, transparent);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

.container {
  width: 100%;
  max-width: 600px;
}

header {
  text-align: center;
  margin-bottom: 40px;
}

.logo-area {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 8px;
}

.logo-area i {
  color: var(--primary);
  width: 32px;
  height: 32px;
}

header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
}

header p {
  color: var(--text-muted);
  font-size: 1.1rem;
}

.sync-card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 32px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.upload-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 32px;
}

.file-label {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px;
  background: rgba(255, 255, 255, 0.03);
  border: 2px dashed var(--border);
  border-radius: 16px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.file-label:hover {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.05);
}

.icon-box {
  width: 48px;
  height: 48px;
  background: rgba(99, 102, 241, 0.1);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
}

.text-box {
  display: flex;
  flex-direction: column;
}

.text-box .title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
}

.text-box .file-name {
  font-size: 1rem;
  color: var(--text);
  word-break: break-all;
}

.action-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.btn-primary {
  width: 100%;
  background: var(--primary);
  color: white;
  border: none;
  padding: 16px 32px;
  font-size: 1.1rem;
  font-weight: 600;
  border-radius: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  transition: transform 0.1s active, background 0.2s ease;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-primary:active {
  transform: scale(0.98);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.status-msg {
  font-size: 0.9rem;
  color: var(--text-muted);
  height: 20px;
}

.result-section {
  margin-top: 32px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
  animation: fadeIn 0.5s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.result-section h3 {
  font-size: 1rem;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--success);
}

audio {
  width: 100%;
  height: 45px;
  margin-bottom: 20px;
}

/* Customizing Audio Player for Dark Theme (Partial) */
audio::-webkit-media-controls-panel {
  background-color: #1e293b;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 8px 16px;
  border-radius: 8px;
  background: rgba(99, 102, 241, 0.1);
  transition: all 0.2s ease;
}

.btn-secondary:hover {
  background: rgba(99, 102, 241, 0.2);
}

footer {
  text-align: center;
  margin-top: 40px;
  font-size: 0.85rem;
  color: var(--text-muted);
}