.percentage-calculator-wrapper {
    --primary-green: #27ae60;
    --hover-green: #2ecc71;
    --bg-grey: #f4f4f4;
    --card-bg: #ffffff;
    --border-grey: #dddddd;
    --text-black: #000000;
    
    background-color: var(--bg-grey);
    padding: 40px 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.percentage-calculator-wrapper * {
    box-sizing: border-box;
}

.main-title {
    color: #333;
    text-align: center;
    margin-bottom: 30px;
    font-size: 2.2rem;
}

.calculator-container {
    display: flex;
    flex-direction: column;
    gap: 25px;
    width: 100%;
    max-width: 500px;
}

.calc-box {
    background-color: var(--card-bg);
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    border: 1px solid var(--border-grey);
    border-top: 5px solid var(--primary-green);
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.calc-box h3 {
    color: var(--primary-green);
    font-size: 1.3rem;
    margin-top: 0;
}

.explanation {
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 5px;
}

.input-group {
    display: flex;
    align-items: center;
    gap: 10px;
    background: #fafafa;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid #eee;
}

.input-group span {
    color: #555;
    font-size: 0.95rem;
    font-weight: 600;
    white-space: nowrap;
}

.input-group input[type="number"] {
    width: 100%;
    background: transparent !important;
    border: none !important;
    border-bottom: 2px solid #ddd !important;
    color: var(--text-black) !important;
    font-size: 1.1rem !important;
    font-weight: bold !important;
    outline: none !important;
    text-align: center !important;
    padding: 5px 0 !important;
    box-shadow: none !important;
}

.input-group input[type="number"]:focus {
    border-color: var(--primary-green) !important;
}

.btn-container {
    display: flex;
    gap: 10px;
    margin-top: 10px;
}

.btn-container button {
    flex: 1;
    padding: 12px;
    border-radius: 8px;
    border: none;
    font-weight: bold;
    cursor: pointer;
    transition: 0.2s;
}

.btn-calc {
    background-color: var(--primary-green);
    color: #fff !important;
}

.btn-calc:hover {
    background-color: var(--hover-green);
}

.btn-reset {
    background-color: #e0e0e0;
    color: #333 !important;
}

.result-box {
    margin-top: 5px;
    padding: 15px;
    background-color: #f1f8f4;
    border-radius: 8px;
    text-align: center;
    border: 1px dashed var(--primary-green);
}

.res-label { color: #666; font-size: 0.75rem; text-transform: uppercase; }
.res-val { color: var(--text-black); font-size: 1.6rem; font-weight: bold; }

.formula-section {
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 12px;
    border: 1px solid var(--border-grey);
}

.formula-section h3 {
    font-size: 1.1rem;
    margin-bottom: 15px;
    color: #333;
    border-bottom: 2px solid var(--primary-green);
    display: inline-block;
}

.formula-item {
    font-size: 0.9rem;
    margin-bottom: 12px;
    color: #444;
}

.formula-item code {
    display: block;
    background: #f9f9f9;
    padding: 8px;
    margin-top: 5px;
    border-radius: 4px;
    color: var(--primary-green);
    font-family: monospace;
    font-weight: bold;
}