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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

/* Loading Overlay */
.loading-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    z-index: 9999;
    justify-content: center;
    align-items: center;
}

.loading-overlay.active {
    display: flex;
}

.loading-spinner {
    text-align: center;
    color: white;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-spinner p {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.loading-hint {
    font-size: 0.95rem;
    opacity: 0.8;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 1; }
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px;
    text-align: center;
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

header p {
    opacity: 0.9;
    font-size: 1.1em;
}

.message {
    padding: 20px;
    margin: 20px;
    border-radius: 10px;
    font-weight: 500;
}

.message.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.tabs {
    display: flex;
    background: #f8f9fa;
    border-bottom: 2px solid #dee2e6;
}

.tab-btn {
    flex: 1;
    padding: 20px;
    background: none;
    border: none;
    font-size: 1.1em;
    font-weight: 600;
    color: #6c757d;
    cursor: pointer;
    transition: all 0.3s ease;
}

.tab-btn:hover {
    background: #e9ecef;
}

.tab-btn.active {
    color: #667eea;
    border-bottom: 3px solid #667eea;
}

.tab-content {
    display: none;
    padding: 40px;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

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

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: #333;
    font-size: 1em;
}

.form-group input[type="text"],
.form-group input[type="number"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e1e8ed;
    border-radius: 8px;
    font-size: 1em;
    transition: all 0.3s ease;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.form-group small {
    display: block;
    margin-top: 5px;
    font-size: 0.85em;
}

.btn {
    padding: 15px 30px;
    font-size: 1.1em;
    font-weight: 600;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    width: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

footer {
    background: #f8f9fa;
    padding: 20px;
    text-align: center;
    color: #6c757d;
    border-top: 1px solid #dee2e6;
}

footer code {
    background: #e9ecef;
    padding: 4px 8px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
}

@media (max-width: 600px) {
    header h1 {
        font-size: 1.8em;
    }

    .container {
        border-radius: 0;
    }

    .tab-content {
        padding: 20px;
    }
}