:root {
    --primary-color: #113B7A;
    --secondary-color: #1D5FD1;
    --text-main: #F3F8FF;
    --text-secondary: #AFC4E8;
    --button-gradient: linear-gradient(180deg, #2B73F6 0%, #1144A6 100%);
    --card-bg: #10233F;
    --border-color: #244D84;
    --deep-navy: #08162B;
    --glow-color: #4FA8FF;
    --gold-color: #F2C14E;
    --divider-color: #1B3357;
}

.page-lich-su-phat-trien {
    font-family: Arial, sans-serif;
    color: var(--text-main); /* Default text color for the page, assuming dark body background */
    background-color: var(--deep-navy); /* Ensure consistency if body background is not fully set by shared */
}

.page-lich-su-phat-trien__container {
    max-width: 1170px;
    margin: 0 auto;
    padding: 20px 16px;
}

/* Hero Section */
.page-lich-su-phat-trien__hero-section {
    padding-top: 10px; /* Small top padding, relying on body padding-top from shared.css */
    padding-bottom: 60px;
    background-color: var(--deep-navy);
    color: var(--text-main);
}

.page-lich-su-phat-trien__hero-container {
    max-width: 1170px;
    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
    padding: 40px 16px;
}

.page-lich-su-phat-trien__hero-content {
    flex: 1 1 45%;
    min-width: 300px;
    text-align: left;
}

.page-lich-su-phat-trien__main-title {
    font-size: clamp(2.2rem, 4vw, 3.2rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
    color: var(--text-main);
}

.page-lich-su-phat-trien__intro-text {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 30px;
    color: var(--text-secondary);
}

.page-lich-su-phat-trien__hero-image {
    flex: 1 1 45%;
    min-width: 300px;
    text-align: center;
}

.page-lich-su-phat-trien__hero-side-image {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

.page-lich-su-phat-trien__cta-buttons {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-top: 30px;
}

.page-lich-su-phat-trien__btn-primary,
.page-lich-su-phat-trien__btn-secondary {
    display: inline-block;
    padding: 14px 28px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 700;
    font-size: 1rem;
    transition: all 0.3s ease;
    white-space: normal; /* Allow text wrapping */
    word-wrap: break-word; /* Allow text wrapping */
    box-sizing: border-box;
    text-align: center;
}

.page-lich-su-phat-trien__btn-primary {
    background: var(--button-gradient);
    color: var(--text-main);
    border: none;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.page-lich-su-phat-trien__btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.page-lich-su-phat-trien__btn-secondary {
    background: transparent;
    color: var(--glow-color);
    border: 2px solid var(--glow-color);
    box-shadow: inset 0 0 0 1px var(--glow-color);
}

.page-lich-su-phat-trien__btn-secondary:hover {
    background-color: rgba(79, 168, 255, 0.1);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(79, 168, 255, 0.2);
}

/* Content Section - Dark Background */
.page-lich-su-phat-trien__content-section {
    padding: 60px 0;
    background-color: var(--deep-navy);
    color: var(--text-main);
}

.page-lich-su-phat-trien__section-title {
    font-size: clamp(1.8rem, 3.5vw, 2.5rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 20px;
    color: var(--text-main);
}

.page-lich-su-phat-trien__section-description {
    font-size: 1rem;
    line-height: 1.6;
    text-align: center;
    max-width: 800px;
    margin: 0 auto 40px auto;
    color: var(--text-secondary);
}

/* Timeline */
.page-lich-su-phat-trien__timeline {
    position: relative;
    padding: 20px 0;
    list-style: none;
}

.page-lich-su-phat-trien__timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 4px;
    background-color: var(--divider-color);
    transform: translateX(-50%);
}

.page-lich-su-phat-trien__timeline-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 60px;
    position: relative;
}

.page-lich-su-phat-trien__timeline-item:nth-child(odd) {
    flex-direction: row-reverse;
}

.page-lich-su-phat-trien__timeline-item:last-child {
    margin-bottom: 0;
}

.page-lich-su-phat-trien__timeline-item::before {
    content: '';
    position: absolute;
    top: 15px;
    left: 50%;
    width: 20px;
    height: 20px;
    background-color: var(--glow-color);
    border-radius: 50%;
    transform: translateX(-50%);
    z-index: 1;
    border: 3px solid var(--deep-navy);
}

.page-lich-su-phat-trien__timeline-year {
    flex: 0 0 150px;
    text-align: center;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--gold-color);
    position: sticky;
    top: 100px; /* Adjust as needed */
    align-self: flex-start;
    padding-top: 10px;
}

.page-lich-su-phat-trien__timeline-content {
    flex: 1 1 40%;
    padding: 20px 30px;
    background-color: var(--card-bg);
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border-color);
}

.page-lich-su-phat-trien__timeline-item:nth-child(odd) .page-lich-su-phat-trien__timeline-content {
    margin-right: calc(150px / 2 + 20px); /* Adjust for year column and gap */
}

.page-lich-su-phat-trien__timeline-item:nth-child(even) .page-lich-su-phat-trien__timeline-content {
    margin-left: calc(150px / 2 + 20px); /* Adjust for year column and gap */
}

.page-lich-su-phat-trien__timeline-heading {
    font-size: 1.5rem;
    color: var(--text-main);
    margin-bottom: 15px;
}

.page-lich-su-phat-trien__timeline-content p {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.page-lich-su-phat-trien__timeline-image {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin-top: 15px;
    display: block;
}

/* Values Section */
.page-lich-su-phat-trien__values-section {
    padding: 60px 0;
    background-color: var(--deep-navy);
    color: var(--text-main);
}

.page-lich-su-phat-trien__values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.page-lich-su-phat-trien__value-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.page-lich-su-phat-trien__value-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

.page-lich-su-phat-trien__value-heading {
    font-size: 1.3rem;
    color: var(--gold-color);
    margin-bottom: 15px;
}

.page-lich-su-phat-trien__value-card p {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* FAQ Section */
.page-lich-su-phat-trien__faq-section {
    padding: 60px 0;
    background-color: var(--deep-navy);
    color: var(--text-main);
}

.page-lich-su-phat-trien__faq-list {
    max-width: 900px;
    margin: 40px auto 0 auto;
}

.page-lich-su-phat-trien__faq-item {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    margin-bottom: 15px;
    overflow: hidden;
    transition: all 0.3s ease;
}

.page-lich-su-phat-trien__faq-item summary {
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 25px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    color: var(--text-main);
    position: relative;
    user-select: none;
}

.page-lich-su-phat-trien__faq-item summary::-webkit-details-marker {
    display: none;
}

.page-lich-su-phat-trien__faq-toggle {
    font-size: 1.5rem;
    line-height: 1;
    color: var(--glow-color);
    transition: transform 0.3s ease;
}

.page-lich-su-phat-trien__faq-item[open] .page-lich-su-phat-trien__faq-toggle {
    transform: rotate(45deg);
}

.page-lich-su-phat-trien__faq-answer {
    padding: 0 25px 20px 25px;
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Bottom CTA Section */
.page-lich-su-phat-trien__cta-bottom-section {
    padding: 80px 0;
    text-align: center;
    background-color: var(--primary-color);
    color: var(--text-main);
    background-image: linear-gradient(rgba(17, 59, 122, 0.9), rgba(29, 95, 209, 0.9)), url('[GALLERY:blog:1920x400:cta_background,abstract_pattern,5mb_brand]');
    background-size: cover;
    background-position: center;
}

.page-lich-su-phat-trien__cta-bottom-container {
    max-width: 800px;
}

.page-lich-su-phat-trien__cta-bottom-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-main);
}

.page-lich-su-phat-trien__cta-bottom-description {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 40px;
    color: var(--text-secondary);
}

/* General image styling */
.page-lich-su-phat-trien img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* Responsive styles */
@media (max-width: 1024px) {
    .page-lich-su-phat-trien__hero-container {
        flex-direction: column-reverse;
        text-align: center;
    }

    .page-lich-su-phat-trien__hero-content,
    .page-lich-su-phat-trien__hero-image {
        flex: 1 1 100%;
        max-width: 100%;
    }

    .page-lich-su-phat-trien__cta-buttons {
        justify-content: center;
    }

    .page-lich-su-phat-trien__timeline::before {
        left: 20px;
    }

    .page-lich-su-phat-trien__timeline-item {
        flex-direction: column;
        align-items: flex-start;
        margin-bottom: 40px;
    }

    .page-lich-su-phat-trien__timeline-item:nth-child(odd) {
        flex-direction: column;
    }

    .page-lich-su-phat-trien__timeline-item::before {
        left: 20px;
        transform: translateX(0);
    }

    .page-lich-su-phat-trien__timeline-year {
        text-align: left;
        padding-left: 50px;
        margin-bottom: 10px;
        position: static;
        flex: none;
    }

    .page-lich-su-phat-trien__timeline-content {
        flex: 1 1 100%;
        margin-left: 50px !important;
        margin-right: 0 !important;
    }
}

@media (max-width: 768px) {
    /* General mobile adaptations */
    .page-lich-su-phat-trien {
        font-size: 16px;
        line-height: 1.6;
    }

    .page-lich-su-phat-trien__container {
        padding-left: 15px;
        padding-right: 15px;
    }

    /* HERO Section */
    .page-lich-su-phat-trien__hero-section {
        padding-top: 10px !important; /* Small top padding, relying on body padding-top from shared.css */
        padding-bottom: 40px;
    }

    .page-lich-su-phat-trien__main-title {
        font-size: 2rem; /* Adjusted for mobile */
        text-align: center;
    }

    .page-lich-su-phat-trien__intro-text {
        font-size: 1rem;
        text-align: center;
    }

    .page-lich-su-phat-trien__cta-buttons {
        flex-direction: column; /* Stack buttons vertically */
        gap: 15px;
        width: 100%;
        max-width: 100%;
        overflow: hidden;
        box-sizing: border-box;
        padding: 0 15px;
    }

    .page-lich-su-phat-trien__btn-primary,
    .page-lich-su-phat-trien__btn-secondary {
        max-width: 100% !important;
        width: 100% !important;
        padding: 12px 20px;
        font-size: 0.95rem;
        white-space: normal !important;
        word-wrap: break-word !important;
        box-sizing: border-box !important;
    }

    /* Content Section */
    .page-lich-su-phat-trien__section-title {
        font-size: 1.8rem;
    }

    .page-lich-su-phat-trien__section-description {
        font-size: 0.9rem;
        margin-bottom: 30px;
    }

    /* Timeline */
    .page-lich-su-phat-trien__timeline::before {
        left: 15px;
    }

    .page-lich-su-phat-trien__timeline-item::before {
        left: 15px;
    }

    .page-lich-su-phat-trien__timeline-year {
        padding-left: 45px;
        font-size: 1.2rem;
    }

    .page-lich-su-phat-trien__timeline-content {
        margin-left: 45px !important;
        padding: 15px 20px;
    }

    .page-lich-su-phat-trien__timeline-heading {
        font-size: 1.3rem;
    }

    .page-lich-su-phat-trien__timeline-content p {
        font-size: 0.9rem;
    }

    /* Values Grid */
    .page-lich-su-phat-trien__values-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    /* FAQ Section */
    .page-lich-su-phat-trien__faq-item summary {
        padding: 15px 20px;
        font-size: 1rem;
    }

    .page-lich-su-phat-trien__faq-answer {
        padding: 0 20px 15px 20px;
        font-size: 0.9rem;
    }

    /* Bottom CTA */
    .page-lich-su-phat-trien__cta-bottom-section {
        padding: 50px 15px;
    }

    .page-lich-su-phat-trien__cta-bottom-title {
        font-size: 1.8rem;
    }

    .page-lich-su-phat-trien__cta-bottom-description {
        font-size: 1rem;
        margin-bottom: 30px;
    }

    /* Universal image responsive styles for content area */
    .page-lich-su-phat-trien img {
        max-width: 100% !important;
        width: 100% !important;
        height: auto !important;
        box-sizing: border-box !important;
    }
    
    .page-lich-su-phat-trien__section,
    .page-lich-su-phat-trien__card,
    .page-lich-su-phat-trien__container,
    .page-lich-su-phat-trien__cta-buttons,
    .page-lich-su-phat-trien__values-grid {
        max-width: 100% !important;
        width: 100% !important;
        box-sizing: border-box !important;
        /* Padding already handled by .page-lich-su-phat-trien__container */
    }

    .page-lich-su-phat-trien__cta-buttons {
        flex-wrap: wrap !important;
        gap: 10px;
    }

    .page-lich-su-phat-trien__hero-image {
        overflow: hidden; /* Prevent image overflow */
    }
}