body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #f3f4f6;
    color: #1f2937;
    margin: 0;
    padding: 20px;
}
.container {
    max-width: 600px;
    margin: 0 auto;
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}
.text-center { text-align: center; }
h1 { margin-bottom: 5px; color: #1e3a8a; }
.subtitle { color: #6b7280; margin-bottom: 30px; }
.menu-box { display: flex; flex-direction: column; gap: 15px; }
.btn {
    display: block;
    padding: 15px;
    text-align: center;
    text-decoration: none;
    font-weight: bold;
    border-radius: 8px;
    transition: background 0.2s;
    border: none;
    cursor: pointer;
    font-size: 16px;
}
.btn-primary { background: #3b82f6; color: white; }
.btn-secondary { background: #4b5563; color: white; }
.btn-success { background: #10b981; color: white; }
.btn-block { width: 100%; }
.back-link { display: inline-block; margin-bottom: 20px; color: #3b82f6; text-decoration: none; }
.upload-area {
    border: 2px dashed #d1d5db;
    padding: 40px 20px;
    text-align: center;
    border-radius: 8px;
    margin-bottom: 20px;
    position: relative;
}
.upload-area input[type=file] { position: absolute; width: 100%; height: 100%; top:0; left:0; opacity: 0; cursor: pointer; }
.upload-label { color: #4b5563; font-weight: 500; }
.hidden { display: none !important; }
.alert { padding: 15px; border-radius: 8px; margin-top: 20px; line-height: 1.5; }
.alert-success { background: #d1fae5; color: #065f46; border: 1px solid #10b981; }
.alert-danger { background: #fee2e2; color: #991b1b; border: 1px solid #ef4444; }
.spinner {
    border: 4px solid rgba(0,0,0,0.1);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border-left-color: #3b82f6;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }