/* Core Styles */
.gst-calculator-container {
    max-width: 600px;
    margin: 30px auto;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: #333;
}

.gst-header {
    text-align: center;
    margin-bottom: 30px;
    color: #0f4c75;
}

.gst-header h1 {
    margin-bottom: 10px;
    font-weight: 700;
}

.gst-header p {
    color: #666;
    font-size: 1.1rem;
}

.gst-card {
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
    padding: 30px;
    margin-bottom: 25px;
}

/* Toggle Buttons */
.mode-toggle {
    display: flex;
    margin-bottom: 25px;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid #ddd;
}

.mode-btn {
    flex: 1;
    padding: 12px 15px;
    background: #f8f9fa;
    border: none;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    font-size: 15px;
}

.mode-btn.active {
    background: #0f4c75;
    color: white;
}

/* Input Groups */
.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #495057;
}

.input-group input, 
.input-group select {
    width: 100%;
    padding: 14px;
    border: 1px solid #ced4da;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s;
    box-sizing: border-box;
}

.input-group input:focus, 
.input-group select:focus {
    border-color: #0f4c75;
    outline: none;
    box-shadow: 0 0 0 3px rgba(15, 76, 117, 0.1);
}

.hidden {
    display: none;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 15px;
    margin: 25px 0;
}

.calc-btn, #gst-reset-btn {
    flex: 1;
    padding: 14px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.calc-btn {
    background: #00b7c2;
    color: white;
}

.calc-btn:hover {
    background: #009da7;
}

#gst-reset-btn {
    background: #f8f9fa;
    border: 1px solid #ddd;
    color: #495057;
}

#gst-reset-btn:hover {
    background: #e9ecef;
}

/* Results Card */
.results-card {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 20px;
    border-left: 4px solid #00b7c2;
}

.result-item {
    display: flex;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px solid #e9ecef;
    font-size: 16px;
}

.result-item.total {
    font-weight: 700;
    font-size: 18px;
    color: #0f4c75;
    border-bottom: none;
    padding-top: 15px;
    margin-top: 5px;
}

/* Info Section */
.gst-info {
    background: #f0f9ff;
    border-radius: 12px;
    padding: 25px;
    border-left: 4px solid #0f4c75;
}

.gst-info h3 {
    color: #0f4c75;
    margin-top: 0;
    margin-bottom: 15px;
}

.gst-info ul {
    padding-left: 20px;
    margin: 0;
}

.gst-info li {
    margin-bottom: 10px;
    line-height: 1.5;
}

/* Responsive Design */
@media (max-width: 650px) {
    .gst-card {
        padding: 20px;
    }
    
    .action-buttons {
        flex-direction: column;
    }
}