:root {
    --main-color: #007AFF; /* Apple의 블루와 유사한 신뢰감 있는 파란색 */
    --text-color: #1d1d1f;   /* 거의 검정에 가까운 짙은 회색 */
    --secondary-text-color: #6e6e73;
    --border-color: #d2d2d7;
    --background-color: #f5f5f7;
    --white-color: #fff;
    --font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
}

.store-header {
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    position: sticky;
    top: 0;
    z-index: 10;
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.store-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
    margin: 0;
}

.store-header nav a {
    margin-left: 1.5rem;
    text-decoration: none;
    color: var(--secondary-text-color);
    font-weight: 500;
    transition: color 0.2s;
}

.store-header nav a:hover {
    color: var(--main-color);
}

.product-page {
    max-width: 1100px;
    margin: 2rem auto;
    padding: 1rem;
}

.product-main-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
    background-color: var(--white-color);
    padding: 2rem;
    border-radius: 12px;
}

.product-image-section img {
    width: 100%;
    border-radius: 8px;
}

.product-name {
    font-size: 1.8rem;
    font-weight: 700;
    margin: 0 0 0.5rem 0;
}

.product-short-description {
    color: var(--secondary-text-color);
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.product-price-container {
    display: flex;
    align-items: baseline;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.product-price {
    font-size: 2.2rem;
    font-weight: 700;
}

.discount-rate {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--main-color);
}

.product-benefits {
    color: var(--secondary-text-color);
    font-size: 0.9rem;
    margin-bottom: 2rem;
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
}

.product-options select {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    margin-bottom: 1rem;
    background-color: var(--background-color);
}

#selected-products {
    background-color: var(--background-color);
    border-radius: 8px;
    padding: 0.5rem 1rem;
    margin-bottom: 1rem;
}

.total-price-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.2rem;
    font-weight: 500;
    padding-top: 1.5rem;
    border-top: 2px solid var(--border-color);
    margin-top: 1.5rem;
}

#total-price {
    color: var(--main-color);
    font-size: 2rem;
    font-weight: 700;
}

.action-buttons {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.action-buttons button {
    padding: 1rem;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    border: 1px solid var(--main-color);
    transition: all 0.2s ease;
}

.buy-now-btn {
    background-color: var(--main-color);
    color: var(--white-color);
}

.buy-now-btn:hover {
    opacity: 0.85;
}

.add-to-cart-btn, .wishlist-btn {
    background-color: var(--white-color);
    color: var(--main-color);
}

.add-to-cart-btn:hover, .wishlist-btn:hover {
    background-color: #f0f7ff;
}

/* Tab Navigation */
.product-content-container {
    margin-top: 3rem;
    background-color: var(--white-color);
    border-radius: 12px;
}

.tab-navigation {
    display: flex;
    border-bottom: 1px solid var(--border-color);
}

.tab-link {
    padding: 1.2rem 1.8rem;
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    color: var(--secondary-text-color);
    margin-bottom: -1px;
}

.tab-link.active {
    border-bottom-color: var(--main-color);
    color: var(--text-color);
}

.tab-link span {
    color: var(--main-color);
    font-weight: 500;
    margin-left: 0.3rem;
}

.tab-content {
    padding: 3rem 2rem;
    display: none;
    line-height: 1.8;
    font-size: 1.05rem;
}

.tab-content.active {
    display: block;
}

.tab-content h3 {
    font-size: 1.6rem;
    margin-bottom: 1.5rem;
}

.tab-content .highlight {
    color: var(--main-color);
}

/* Sticky Purchase Bar */
.sticky-purchase-bar {
    position: fixed;
    bottom: -100px; /* Initially hidden */
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    border-top: 1px solid var(--border-color);
    box-shadow: 0 -2px 10px rgba(0,0,0,0.05);
    display: flex;
    justify-content: center;
    transition: bottom 0.3s ease-in-out;
}

.sticky-purchase-bar.visible {
    bottom: 0;
}

.sticky-purchase-bar .buy-now-btn {
    width: 100%;
    max-width: 500px;
    padding: 1.2rem;
    font-size: 1.2rem;
}

@media (max-width: 768px) {
    .product-main-container {
        grid-template-columns: 1fr;
    }

    .store-header {
        flex-direction: column;
        gap: 1rem;
    }
}