* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Roboto, sans-serif;
}

:root {
    --primary-color: #1976D2;
    /* Main color */
    --secondary-color: #000000;
    /* Black for text and accents */
    --white: #FFFFFF;
    /* White for backgrounds */
    --text-dark: #000000;
    /* Black for text */
    --light-text: #FFFFFF;
    /* White for text on dark backgrounds */
    --gradient-start: #1976D2;
    /* Gradient with primary color */
    --gradient-end: #adb5bd;
    /* Slightly darker shade of #1976D2 */
    --hover-color: #000000;
    /* Black for hover effects */
}

body {
    font-family: 'Roboto', sans-serif;
    color: var(--text-dark);
    background-color: var(--white);
    /* White background */
    scroll-behavior: smooth;
    margin: 0;
}

/* Header */
#header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    background: var(--white);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.logo-container {
    display: flex;
    align-items: center;
}

.logo-nav {
    display: flex;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.logo-nav img {
    height: 60px;
    margin-right: 10px;
    border-radius: 40px;
}

.menu {
    display: flex;
    align-items: center;
}

.menu a {
    margin: 0 30px;
    text-decoration: none;
    color: var(--text-dark);
    font-size: 16px;
    transition: color 0.3s ease;
}

.menu a:hover {
    color: var(--primary-color);
}

.menu a:focus {
    outline: none;
    background-color: rgba(25, 118, 210, 0.1);
    /* Light #1976D2 */
    border-radius: 4px;
    padding: 2px 4px;
}

.right-section {
    display: flex;
    align-items: center;
    gap: 12px;
}

.login-btn {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 6px 15px;
    border-radius: 5px;
    text-decoration: none;
    font-size: 16px;
    transition: all 0.3s ease;
}

.login-btn:hover {
    background: var(--primary-color);
    color: var(--light-text);
}

.donate-btn {
    background: var(--primary-color);
    color: var(--light-text);
    padding: 8px 20px;
    border-radius: 5px;
    text-decoration: none;
    font-size: 16px;
    transition: background 0.3s ease;
}

.donate-btn:hover {
    background: var(--hover-color);
    /* Black on hover */
    color: var(--light-text);
}

/* Hamburger Icon */
.hamburger {
    display: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-dark);
}

/* Other styles unchanged, only showing modified section */
.viet-nam-header {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end) 80%);
    /* Blue to light white */
    color: var(--light-text);
    padding: 60px 0;
    margin-top: 90px;
    text-align: center;
}

.viet-nam-header h1 {
    font-family: 'Lobster', cursive;
    font-size: 3rem;
}

.viet-nam-header img {
    width: 80px;
    height: 80px;
    animation: flagWaving 3s infinite ease-in-out;
    transform-origin: center;
}

.img-fluid {
    width: 400px;
    height: 450px;
}

.img-fluid.rounded-circle {
    width: 550px;
    height: 400px;
}

.img-fluid.rounded {
    width: 450px;
    height: 300px;
}

.img-fluid.roundedhand {
    width: 500px;
    height: 500px;
}

/* Animations */
@keyframes flagWaving {

    0%,
    50%,
    100% {
        transform: rotate(0deg);
    }

    25% {
        transform: rotate(10deg);
    }

    75% {
        transform: rotate(-10deg);
    }
}

@keyframes heartFly {
    0% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 1;
    }

    100% {
        transform: translate(-50%, -100%) scale(0.5);
        opacity: 0;
    }
}

/* Section Titles */
.section-title {
    font-family: 'Lobster', cursive;
    color: var(--primary-color);
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    position: relative;
    text-align: center;
}

.section-title::after {
    content: '';
    width: 50px;
    height: 4px;
    background: linear-gradient(90deg, var(--gradient-start), var(--gradient-end));
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
}

.who-we-are {
    background: var(--white);
    /* White background */
    padding: 60px 0;
}

.image-wrapper {
    position: relative;
}

.image-wrapper img {
    border: 4px solid transparent;
    background: linear-gradient(45deg, var(--primary-color), var(--gradient-end));
    padding: 4px;
    border-radius: 50%;
    max-width: 80%;
}

.heart-animation {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 40px;
    height: 40px;
    background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="red"><path d="M12 21.35l-1.45-1.32C5.4 15.36 2 12.28 2 8.5 2 5.42 4.42 3 7.5 3c1.74 0 3.41.81 4.5 2.09C13.09 3.81 14.76 3 16.5 3 19.58 3 22 5.42 22 8.5c0 3.78-3.4 6.86-8.55 11.54L12 21.35z"/></svg>') no-repeat center;
    animation: heartFly 2s infinite;
}

.vision-mission {
    background: var(--white);
    /* White background */
    padding: 60px 0;
}

.mission-card {
    background: var(--white);
    padding: 1rem;
    margin-bottom: 1rem;
    border-radius: 10px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
    /* Subtle black shadow */
    display: flex;
    align-items: center;
    transition: transform 0.3s ease;
}

.mission-card i {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-right: 1rem;
}

.mission-card:hover {
    transform: scale(1.03);
}

.map-wrapper {
    margin-top: 40px;
}

#map {
    height: 400px;
    border-radius: 10px;
}

.our-story {
    background: var(--white);
    /* White background */
}

.timeline {
    position: relative;
    padding: 2rem 0;
}

.timeline-item {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

.timeline-content {
    flex: 1;
    padding: 1rem;
    color: var(--text-dark);
}

.timeline-image img {
    flex: 1;
    border: 3px solid var(--primary-color);
    border-radius: 10px;
}

.before-after {
    position: relative;
    overflow: hidden;
}

.before-after::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 50%;
    height: 100%;
    background: url('/img/before-placeholder.jpg') no-repeat center/cover;
    transition: width 0.5s ease;
}

.before-after:hover::before {
    width: 0;
}

.blockquote {
    font-family: 'Dancing Script', cursive;
    color: var(--primary-color);
    font-size: 1.5rem;
    border-left: 5px solid var(--primary-color);
    padding-left: 1rem;
}

.journey {
    background: var(--white);
    /* White background */
    color: var(--text-dark);
}

.counter {
    font-family: 'Roboto', sans-serif;
    font-size: 2.5rem;
    color: var(--primary-color);
}

.carousel-caption {
    border-radius: 5px;
    color: var(--light-text);
    width: 400px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    position: absolute;
    left: 50%;
    bottom: 20px;
    transform: translateX(-50%);
}

.carousel-item img {
    border-radius: 10px;
}

.message {
    background: var(--white);
    /* White background */
    color: var(--text-dark);
    padding: 60px 0;
}

.message .blockquote {
    font-family: 'Dancing Script', cursive;
    color: var(--primary-color);
    font-size: 2rem;
    background: rgba(25, 118, 210, 0.1);
    /* Light #1976D2 */
    padding: 1rem;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.quote-icon {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-right: 0.5rem;
}

.btn-primary {
    background: var(--primary-color);
    border-color: var(--primary-color);
    padding: 0.75rem 2rem;
    font-size: 1.2rem;
    border-radius: 25px;
    color: var(--light-text);
    transition: all 0.3s ease;
}

.btn-primary:hover {
    background: var(--hover-color);
    /* Black on hover */
    border-color: var(--hover-color);
    color: var(--light-text);
}

/* Accessibility */
img {
    max-width: 100%;
    height: auto;
}

a:focus,
button:focus {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* Responsive Design */
@media (max-width: 768px) {
    #header {
        flex-direction: column;
        padding: 15px;
        height: auto;
        min-height: 50px;
    }

    .logo-container {
        justify-content: space-between;
        width: 100%;
        margin-bottom: 15px;
    }

    .logo-nav {
        font-size: 28px;
        font-weight: bold;
        display: flex;
        align-items: center;
        gap: 12px;
    }

    .logo-nav img {
        height: 70px;
        width: auto;
    }

    .menu {
        display: none;
        flex-direction: column;
        width: 100%;
        background: var(--white);
        position: absolute;
        top: 100px;
        left: 0;
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
    }

    .menu.active {
        display: flex;
    }

    .menu a {
        margin: 10px 0;
        text-align: center;
        padding: 10px 0;
        border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    }

    .right-section {
        justify-content: flex-start;
        width: 100%;
        gap: 12px;
        margin-top: 10px;
        padding-left: 5px;
    }

    .login-btn,
    .donate-btn {
        padding: 10px 15px;
        font-size: 15px;
        min-width: 110px;
        text-align: center;
        border-radius: 5px;
    }

    .hamburger {
        display: block;
        position: absolute;
        top: 90px;
        right: 15px;
        font-size: 24px;
        cursor: pointer;
        color: var(--text-dark);
        margin-top: 10px;
    }

    .viet-nam-header {
        margin-top: 120px;
        padding: 40px 0;
    }

    .section-title {
        font-size: 2rem;
    }

    .timeline-item,
    .timeline-item:nth-child(even) {
        flex-direction: column;
    }

    .timeline-image,
    .timeline-content {
        width: 100%;
        margin-bottom: 1rem;
    }

    .message .blockquote {
        font-size: 1.5rem;
    }

    .image-wrapper img {
        max-width: 60%;
    }

    .image-wrapper img.rounded-circle {
        max-width: 100%;
        display: block;
        margin: 0 auto;
        height: 70%;
    }
}

@media (max-width: 576px) {
    .logo-nav {
        font-size: 30px;
    }

    .logo-nav img {
        height: 60px;
    }

    .btn-primary {
        padding: 0.5rem 1.5rem;
        font-size: 1rem;
    }
}