* { margin: 0; padding: 0; box-sizing: border-box; font-family: Arial, sans-serif; }
body { background: #f5f7fa; padding: 20px; }
.container { max-width: 900px; margin: 0 auto; background: white; padding: 25px; border-radius: 12px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
h1 { text-align: center; color: #2d3748; margin-bottom: 20px; }

.tabs { display: flex; gap: 10px; margin-bottom: 20px; }
.tab-btn { padding: 10px 20px; border: none; background: #e2e8f0; border-radius: 6px; cursor: pointer; }
.tab-btn.active { background: #3182ce; color: white; }

.tab-content { display: none; }
.tab-content.active { display: block; }

.form-group { margin-bottom: 15px; }
label { display: block; margin-bottom: 5px; color: #4a5568; }
input, textarea { width: 100%; padding: 10px; border: 1px solid #e2e8f0; border-radius: 6px; font-size: 14px; }
.send-btn { background: #38a169; color: white; padding: 10px 25px; border: none; border-radius: 6px; cursor: pointer; }

.mail-item { padding: 15px; border-bottom: 1px solid #e2e8f0; }
.mail-item h3 { font-size: 16px; color: #2d3748; margin-bottom: 5px; }
.mail-item p { font-size: 14px; color: #718096; }
.loading { text-align: center; padding: 20px; color: #718096; }