:root {
    --primary-color: #25D366;
    --secondary-color: #128C7E;
    --font-stack: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --success-bg: #d4edda;
    --error-bg: #f8d7da;
    --warning-bg: #fff3cd;
    --info-bg: #e1f5fe;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: var(--font-stack);
}

body {
    background: linear-gradient(135deg, #f9f9f9, #e6f7e6);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 450px;
    overflow: hidden;
    position: relative;
}

.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 25px 20px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.15) 0%, rgba(255,255,255,0) 70%);
    transform: rotate(30deg);
}

.logo {
    font-size: 2.2rem;
    margin-bottom: 8px;
}

.title {
    font-weight: 700;
    letter-spacing: 1px;
    margin-bottom: 5px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.subtitle {
    opacity: 0.9;
    font-weight: 300;
}

.loader {
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    margin: 20px auto;
    display: none;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.result {
    margin-top: 20px;
    padding: 15px;
    border-radius: 10px;
    display: none;
    text-align: center;
    animation: fadeIn 0.5s ease;
}

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

.success {
    background-color: var(--success-bg);
    color: #155724;
    border: 1px solid #c3e6cb;
}

.error {
    background-color: var(--error-bg);
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.warning {
    background-color: var(--warning-bg);
    color: #856404;
    border-left: 4px solid #ffc107;
    padding: 10px;
    border-radius: 5px;
    margin-bottom: 15px;
    font-size: 0.9rem;
}

.info-text {
    color: #666;
    font-size: 0.9rem;
    margin-top: 15px;
    line-height: 1.5;
    padding: 12px;
    background: var(--info-bg);
    border-radius: 10px;
    border-left: 4px solid var(--primary-color);
}

.footer {
    text-align: center;
    padding: 15px 20px;
    color: #666;
    font-size: 0.85rem;
    border-top: 1px solid #eee;
}

@media (max-width: 480px) {
    .container {
        border-radius: 10px;
    }
    
    .header {
        padding: 20px 15px;
    }
    
    .title {
        font-size: 1.6rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
}