:root {
    --page-about-primary-color: #017439;
    --page-about-secondary-color: #FFFFFF;
    --page-about-background-color: #FFFFFF; /* Explicitly set as per rule */
    --page-about-text-color-dark: #333333; /* For contrast on white background */
    --page-about-text-color-light: #FFFFFF; /* For text on primary/dark backgrounds */
    --page-about-button-register: #990000; /* Adjusted for WCAG AA contrast with yellow text */
    --page-about-button-login: #990000; /* Adjusted for WCAG AA contrast with yellow text */
    --page-about-button-font: #FFFF00; /* Specified yellow font */
    --page-about-padding-section: 60px;
    --page-about-padding-section-mobile: 30px;
}

.page-about {
    background-color: var(--page-about-background-color);
    color: var(--page-about-text-color-dark);
    font-family: 'Roboto', sans-serif; /* Example font */
    line-height: 1.6;
    padding-top: 10px; /* Small top padding for first section to prevent header overlap */
}

/* Hero Section */
.page-about__hero-section {
    display: flex;
    flex-direction: column; /* Default to column for mobile-first and desktop as per '上图下文' */
    align-items: center;
    text-align: center;
    padding-bottom: var(--page-about-padding-section);
    background-color: var(--page-about-primary-color); /* Hero section can have primary color background */
    color: var(--page-about-text-color-light);
    overflow: hidden; /* Prevent image overflow */
}

.page-about__hero-visual {
    width: 100%;
    max-width: 100%;
    margin-bottom: 20px; /* Space between image and content */
}

.page-about__hero-visual img {
    width: 100%;
    height: auto;
    display: block;
    object-fit: cover;
    aspect-ratio: 16/9; /* Maintain aspect ratio */
}

.page-about__hero-content {
    max-width: 960px;
    padding: 0 20px;
}

.page-about__hero-title {
    font-size: clamp(1.8rem, 4vw, 2.8rem); /* Use clamp for H1 */
    font-weight: 700;
    margin-bottom: 15px;
    line-height: 1.2;
    color: var(--page-about-text-color-light);
}

.page-about__hero-description {
    font-size: 1.1rem;
    margin-bottom: 30px;
    max-width: 760px;
    margin-left: auto;
    margin-right: auto;
    color: var(--page-about-text-color-light);
}

.page-about__hero-cta-button {
    display: inline-block;
    background-color: var(--page-about-button-register); /* Red for CTA */
    color: var(--page-about-button-font); /* Yellow for font */
    padding: 14px 30px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.1rem;
    transition: background-color 0.3s ease;
    border: none;
    cursor: pointer;
}

.page-about__hero-cta-button:hover {
    background-color: #770000; /* Darker red on hover for contrast */
}

/* General Section Styling */
.page-about__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.page-about__section-title {
    font-size: clamp(1.8rem, 3.5vw, 2.5rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 40px;
    color: var(--page-about-primary-color);
}

.page-about__introduction-section,
.page-about__mission-vision-section,
.page-about__values-section,
.page-about__why-choose-section,
.page-about__contact-section {
    padding: var(--page-about-padding-section) 0;
    background-color: var(--page-about-background-color);
}

/* Content Wrapper for text and image */
.page-about__content-wrapper {
    display: flex;
    flex-direction: column; /* Default for mobile */
    gap: 40px;
    align-items: center;
}

.page-about__content-wrapper--reverse {
    flex-direction: column-reverse; /* For mission/vision section on mobile */
}

.page-about__text-content {
    flex: 1;
    max-width: 100%;
}

.page-about__text-content h3 {
    font-size: 1.5rem;
    color: var(--page-about-primary-color);
    margin-bottom: 15px;
}

.page-about__text-content p {
    margin-bottom: 15px;
}

.page-about__image-content {
    flex: 1;
    max-width: 100%;
}

.page-about__image-content img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 8px;
    object-fit: cover;
    min-width: 200px; /* Enforce min size for content images */
    min-height: 200px; /* Enforce min size for content images */
}

/* Values Section specific */
.page-about__values-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    list-style: none;
    padding: 0;
    margin: 0;
    text-align: center;
}

.page-about__value-item {
    background-color: #f8f8f8; /* Slightly off-white for cards */
    padding: 30px 20px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.page-about__value-item img {
    width: 200px; /* Explicit display width */
    height: 200px; /* Explicit display height */
    object-fit: contain; /* Contain for icons/abstract images */
    margin-bottom: 20px;
    display: block; /* Ensure it's a block element */
}

.page-about__value-item h3 {
    font-size: 1.3rem;
    color: var(--page-about-primary-color);
    margin-bottom: 10px;
}

.page-about__advantage-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.page-about__advantage-list li {
    margin-bottom: 15px;
    padding-left: 25px;
    position: relative;
}

.page-about__advantage-list li::before {
    content: '✅'; /* Checkmark icon */
    position: absolute;
    left: 0;
    color: var(--page-about-primary-color);
}

.page-about__cta-button {
    display: inline-block;
    background-color: var(--page-about-primary-color);
    color: var(--page-about-text-color-light);
    padding: 12px 25px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.3s ease;
    border: none;
    cursor: pointer;
    margin-top: 20px;
}

.page-about__cta-button:hover {
    background-color: #005a2e; /* Darker green on hover */
}

.page-about__cta-button--contact {
    background-color: var(--page-about-primary-color); /* Contact button uses primary color */
    color: var(--page-about-text-color-light);
}

.page-about__contact-description {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 30px auto;
    font-size: 1.1rem;
}

/* Responsive Styles */
@media (min-width: 769px) {
    .page-about__hero-section {
        padding-top: 10px; /* Keep consistent small top padding */
        padding-bottom: var(--page-about-padding-section);
    }
    .page-about__hero-visual {
        margin-bottom: 40px; /* Add space below image as per '上图下文' */
    }
    .page-about__hero-content {
        position: static; /* Ensure no overlap */
        margin-top: 0; /* Ensure no overlap */
        background-color: transparent; /* No overlay */
        padding: 0 20px; /* Adjust padding */
        max-width: 960px; /* Keep max width */
    }

    .page-about__content-wrapper {
        flex-direction: row;
        text-align: left;
    }
    .page-about__content-wrapper--reverse {
        flex-direction: row-reverse;
    }
    .page-about__text-content {
        padding-right: 30px;
    }
    .page-about__image-content {
        padding-left: 30px;
    }
    .page-about__values-list {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); /* Adjust for 5 items */
    }
}

@media (max-width: 768px) {
    .page-about__hero-section {
        padding-top: 10px; /* Small top padding on mobile */
    }
    .page-about__hero-content {
        padding: 20px;
        margin-top: 0; /* No overlap on mobile */
        background-color: var(--page-about-primary-color); /* Consistent background */
    }
    /* Mobile content images must be responsive and not overflow */
    .page-about__hero-visual img,
    .page-about__image-content img,
    .page-about__value-item img {
        max-width: 100%;
        height: auto;
    }
    .page-about__introduction-section,
    .page-about__mission-vision-section,
    .page-about__values-section,
    .page-about__why-choose-section,
    .page-about__contact-section {
        padding: var(--page-about-padding-section-mobile) 0;
    }
    .page-about__section-title {
        margin-bottom: 25px;
    }
    .page-about__content-wrapper {
        gap: 30px;
    }
}