* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: #f4f6f8;
    color: #333;
    padding: 20px;
}

.app-container {
    max-width: 650px;
    margin: 0 auto;
    background: #ffffff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

header h2 {
    color: #1a202c;
    margin-bottom: 25px;
    text-align: center;
    font-weight: 600;
}

.app-description {
    margin-top: -12px;
    margin-bottom: 24px;
    text-align: center;
    font-size: 14px;
    line-height: 1.5;
    color: #4a5568;
}

.input-grid {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
}

.input-group {
    flex: 1;
}

.input-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 6px;
    color: #4a5568;
}

.input-group input, .input-group select {
    width: 100%;
    padding: 10px;
    border: 1px solid #cbd5e0;
    border-radius: 6px;
    font-size: 15px;
}

.options-row {
    margin-bottom: 20px;
}

.format-row {
    margin-bottom: 18px;
}

.field-hint {
    margin-top: 8px;
    font-size: 12px;
    color: #718096;
}

.checkbox-label {
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.weekend-selector {
    background: #f7fafc;
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 25px;
    border: 1px solid #edf2f7;
}

.weekend-selector label {
    font-size: 13px;
    font-weight: 600;
    color: #4a5568;
    display: block;
    margin-bottom: 10px;
}

.checkbox-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

.checkbox-grid label {
    font-weight: 400;
    font-size: 13px;
    cursor: pointer;
}

button {
    width: 100%;
    background-color: #3182ce;
    color: white;
    border: none;
    padding: 14px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.2s ease;
}

button:hover {
    background-color: #2b6cb0;
}

.results-panel {
    margin-top: 30px;
    padding: 20px;
    background-color: #ebf8ff;
    border-left: 4px solid #3182ce;
    border-radius: 4px;
}

.results-panel.hidden {
    display: none;
}

.hidden {
    display: none;
}

.results-panel h3 {
    margin-bottom: 15px;
    color: #2b6cb0;
    font-size: 16px;
}

.metric-row, .metric-row-highlight {
    display: flex;
    justify-content: space-between;
    padding: 8px 0;
    font-size: 15px;
    border-bottom: 1px dashed #bee3f8;
}

.metric-row-highlight {
    border-bottom: none;
    font-size: 17px;
    color: #2c5282;
    padding-top: 12px;
}

.ad-banner-slot {
    margin: 18px auto;
    display: flex;
    justify-content: center;
}

.ad-banner-placeholder {
    width: min(100%, 728px);
    min-height: 90px;
    border: 2px dashed #a0aec0;
    border-radius: 6px;
    background: #f8fafc;
    color: #4a5568;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.2px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 8px;
}

.flatpickr-input[readonly] {
    background-color: #fff;
    cursor: pointer;
}

@media (max-width: 640px) {
    .input-grid {
        flex-direction: column;
        gap: 16px;
    }

    .checkbox-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}