body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f7f6;
    margin: 0;
    display: flex;
    justify-content: center;
    color: #333;
}

.app-container {
    width: 100%;
    max-width: 400px;
    padding: 20px;
    text-align: center;
}

header h1 { color: #2c3e50; font-size: 1.5rem; }

.card {
    background: white;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    margin: 20px 0;
}

.btn-main {
    background-color: #27ae60;
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.2rem;
    border-radius: 50px;
    cursor: pointer;
    width: 100%;
    transition: background 0.3s;
}

.btn-main:disabled {
    background-color: #95a5a6;
    cursor: not-allowed;
}

.log-container {
    margin-top: 30px;
    text-align: left;
}

#status-text.error { color: #e74c3c; font-weight: bold; }
#status-text.success { color: #27ae60; font-weight: bold; }