/* --- 1. Cài đặt Biến & Reset CSS --- */
:root {
    --bg-color: #fcfcf9;
    --text-color: #333;
    --primary-color: #006A4E;
    --accent-color: #F9A825;
    --card-bg: #FFFFFF;
    --nav-bg: rgba(255, 255, 255, 0.85);
    --shadow: 0 4px 15px rgba(0, 0, 0, 0.07);
    --border-color: #eee;
    --hero-overlay: rgba(0, 0, 0, 0.3);
    --hero-text: #FFFFFF;
    --table-header-bg: #e0e0e0;
}

html.dark {
    --bg-color: #0A192F;
    --text-color: #E0E0E0;
    --primary-color: #8BC34A;
    --accent-color: #FDEBCF;
    --card-bg: #1D2A43;
    --nav-bg: rgba(29, 42, 67, 0.85);
    --shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    --border-color: #3a4a6b;
    --hero-overlay: rgba(0, 0, 0, 0.5);
    --hero-text: #FFFFFF;
    --table-header-bg: #2d3b50;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Montserrat', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
    line-height: 1.6;
}

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

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.3s ease;
}

a:hover {
    color: var(--accent-color);
}

section {
    padding: 80px 5%;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

h1, h2, h3, h4 {
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--primary-color);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.2rem; text-align: center; }
h3 { font-size: 1.5rem; color: var(--accent-color); }
h4 { font-size: 1.2rem; }

p {
    margin-bottom: 15px;
    font-size: 1rem;
}

/* Ẩn ngôn ngữ không được chọn */
[lang="en"] { display: none; }

/* --- 2. Header & Navigation --- */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: var(--nav-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s ease;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 5%;
    max-width: 1300px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    font-weight: 900;
    font-size: 1.5rem;
    color: var(--primary-color);
}

.logo img {
    height: 50px;
    width: 50px;
    margin-right: 10px;
    border-radius: 50%;
    object-fit: cover;
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin-left: 25px;
}

.nav-links a {
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
}

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

.controls button {
    background: none;
    border: 2px solid var(--border-color);
    color: var(--text-color);
    cursor: pointer;
    border-radius: 50px;
    font-weight: 600;
    transition: all 0.3s ease;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    margin-left: 10px;
}

#lang-toggle {
    padding: 0 10px;
    width: auto;
}

#dark-mode-toggle {
    font-size: 1.2rem;
}

.controls button:hover {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: #fff;
}

.menu-toggle {
    display: none;
    font-size: 1.5rem;
    background: none;
    border: none;
    color: var(--primary-color);
    cursor: pointer;
    margin-left: 15px;
}

/* --- 3. Hero Section (Manual Slideshow) --- */
#hero {
    height: 100vh;
    min-height: 600px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--hero-text);
    padding: 0;
}

.slideshow-container {
    width: 100%;
    height: 100%;
    position: relative;
}

.hero-slide {
    display: none;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
}

.hero-slide::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--hero-overlay);
}

.fade {
    animation-name: fade;
    animation-duration: 1.5s;
}

@keyframes fade {
    from {opacity: .4}
    to {opacity: 1}
}

.hero-content {
    position: absolute;
    z-index: 2;
    max-width: 800px;
    padding: 0 5%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.hero-content h1 {
    font-size: 4rem;
    font-weight: 900;
    color: var(--hero-text);
    margin-bottom: 20px;
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.7);
}

.hero-content p {
    font-size: 1.5rem;
    font-weight: 500;
    text-shadow: 1px 1px 4px rgba(0, 0, 0, 0.7);
}

.prev, .next {
    cursor: pointer;
    position: absolute;
    top: 50%;
    width: auto;
    padding: 16px;
    margin-top: -22px;
    color: white;
    font-weight: bold;
    font-size: 24px;
    transition: 0.3s ease;
    border-radius: 0 3px 3px 0;
    user-select: none;
    z-index: 3;
    background-color: rgba(0,0,0,0.3);
}

.next {
    right: 0;
    border-radius: 3px 0 0 3px;
}

.prev {
    left: 0;
}

.prev:hover, .next:hover {
    background-color: rgba(0,0,0,0.6);
}


/* --- 4. About Section --- */
#about .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

.about-text ul {
    list-style: none;
    margin-top: 20px;
}

.about-text li {
    font-size: 1.1rem;
    margin-bottom: 15px;
    display: flex;
    align-items: flex-start;
}

.about-text li i {
    color: var(--accent-color);
    margin-right: 15px;
    font-size: 1.2rem;
    margin-top: 4px;
}

.about-image {
    text-align: center;
}

.about-image img {
    max-width: 80%;
    border-radius: 15px;
    box-shadow: var(--shadow);
}

/* --- 5. Problem Section --- */
#problem {
    background-color: var(--card-bg);
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.problem-card {
    background-color: var(--bg-color);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.problem-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.problem-card i {
    font-size: 3rem;
    color: var(--accent-color);
    margin-bottom: 20px;
}

.problem-card h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: 15px;
}

.solution {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 2px solid var(--accent-color);
}

.solution strong {
    color: var(--primary-color);
}

/* --- 6. How It Works Section --- */
#how-it-works {
    background-color: var(--bg-color);
}

.how-it-works-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.step-card {
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    text-align: center;
    position: relative;
}

.step-card .step-number {
    position: absolute;
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary-color);
    color: #fff;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    border: 3px solid var(--bg-color);
}

.step-card i {
    font-size: 3rem;
    color: var(--accent-color);
    margin-top: 30px;
    margin-bottom: 20px;
}

.step-card h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
}

/* --- 7. Target Audience Section --- */
#audience {
    background-color: var(--card-bg);
}

.audience-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.audience-card {
    background-color: var(--bg-color);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
}

.audience-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.audience-card i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.audience-card h3 {
    color: var(--accent-color);
    font-size: 1.4rem;
    margin-bottom: 15px;
}

.audience-card ul {
    list-style: none;
    text-align: left;
    margin-top: 20px;
}

.audience-card li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    font-size: 0.95rem;
}

.audience-card li::before {
    content: '•';
    color: var(--accent-color);
    position: absolute;
    left: 0;
}


/* --- 8. Core Values Section --- */
.values-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.value-card {
    background-color: var(--card-bg);
    border-radius: 15px;
    box-shadow: var(--shadow);
    overflow: hidden;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.value-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.value-card .icon {
    font-size: 4rem;
    padding: 40px 20px 20px 20px;
    color: var(--accent-color);
}

.value-card h3 {
    background-color: var(--primary-color);
    color: #fff;
    padding: 20px;
    margin: 0;
    font-size: 1.4rem;
}

.value-card p {
    padding: 30px;
    font-size: 0.95rem;
}

/* --- 9. Competitor Analysis Section --- */
#comparison {
    background-color: var(--card-bg);
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 40px;
    box-shadow: var(--shadow);
    border-radius: 10px;
    overflow: hidden;
}

.comparison-table th, .comparison-table td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.comparison-table th {
    background-color: var(--table-header-bg);
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1.1rem;
}

.comparison-table tr:nth-child(even) {
    background-color: var(--bg-color);
}

.comparison-table tr:hover {
    background-color: var(--border-color);
}

.comparison-table .feature {
    font-weight: 500;
}

/* --- 10. Advantages Section --- */
#advantages {
    background-color: var(--bg-color);
}

.advantages-list {
    max-width: 900px;
    margin: 40px auto 0;
    list-style: none;
}

.advantages-list li {
    display: flex;
    align-items: center;
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease;
}

.advantages-list li:hover {
    transform: translateX(10px);
}

.advantages-list i {
    font-size: 1.5rem;
    color: var(--accent-color);
    margin-right: 20px;
    width: 40px;
    text-align: center;
}

/* --- 11. Testimonials Section --- */
#testimonials {
    background-color: var(--card-bg);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.testimonial-card {
    background-color: var(--bg-color);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    border-top: 5px solid var(--accent-color);
    position: relative;
}

.testimonial-card .quote-icon {
    font-size: 2.5rem;
    color: var(--accent-color);
    position: absolute;
    top: 20px;
    left: 20px;
    opacity: 0.5;
}

.testimonial-card p {
    font-style: italic;
    font-size: 1.1rem;
    margin-top: 40px;
    margin-bottom: 20px;
}

.testimonial-card .author {
    font-weight: 700;
    color: var(--primary-color);
}

.testimonial-card .role {
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
}

/* --- 12. SWOT Section --- */
.swot-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.swot-card {
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    border-left: 5px solid;
}

.swot-card h3 {
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-color);
}

.swot-card ul {
    list-style: none;
}

.swot-card li {
    position: relative;
    padding-left: 25px;
    margin-bottom: 10px;
}

.swot-card li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 7px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

#swot-s { border-color: #4CAF50; }
#swot-s h3 { color: #4CAF50; }
#swot-s li::before { background-color: #4CAF50; }

#swot-w { border-color: #FFC107; }
#swot-w h3 { color: #FFC107; }
#swot-w li::before { background-color: #FFC107; }

#swot-o { border-color: #03A9F4; }
#swot-o h3 { color: #03A9F4; }
#swot-o li::before { background-color: #03A9F4; }

#swot-t { border-color: #F44336; }
#swot-t h3 { color: #F44336; }
#swot-t li::before { background-color: #F44336; }


/* --- 13. CTA Section --- */
#cta {
    background-color: var(--primary-color);
    text-align: center;
    color: #fff;
}

#cta h2 {
    color: #fff;
}

#cta p {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 30px auto;
}

.cta-button {
    background-color: var(--accent-color);
    color: #333;
    padding: 15px 40px;
    border-radius: 50px;
    font-weight: 700;
    font-size: 1.1rem;
    text-transform: uppercase;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease, background-color 0.3s ease;
}

.cta-button:hover {
    background-color: #fff;
    color: var(--primary-color);
    transform: translateY(-5px);
}

/* --- 14. Footer (Porto's Style) --- */
footer {
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-color);
    padding: 60px 5% 30px 5%;
    color: var(--text-color);
}

.footer-top-container {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr 1.5fr;
    gap: 30px;
    max-width: 1300px;
    margin: 0 auto 50px auto;
}

#footer-brand img {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 20px;
}

#footer-brand .social-links a {
    display: inline-block;
    height: 40px;
    width: 40px;
    background-color: var(--border-color);
    margin: 0 10px 10px 0;
    text-align: center;
    line-height: 40px;
    border-radius: 50%;
    color: var(--primary-color);
    transition: all 0.5s ease;
    font-size: 1.2rem;
}

#footer-brand .social-links a:hover {
    color: #fff;
    background-color: var(--accent-color);
}

.footer-col h4 {
    font-size: 1.1rem;
    color: var(--primary-color);
    margin-bottom: 25px;
    text-transform: uppercase;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li:not(:last-child) {
    margin-bottom: 10px;
}

.footer-col ul li a {
    font-size: 0.95rem;
    color: var(--text-color);
    display: block;
    transition: all 0.3s ease;
}

.footer-col ul li a:hover {
    color: var(--primary-color);
    padding-left: 8px;
}

#footer-newsletter .newsletter-form p {
    font-size: 0.95rem;
    margin-bottom: 15px;
}

#footer-newsletter .newsletter-form input[type="email"] {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    margin-bottom: 10px;
    background-color: var(--bg-color);
    color: var(--text-color);
}

#footer-newsletter .newsletter-form button {
    background-color: var(--primary-color);
    color: #fff;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    font-weight: 600;
}

#footer-newsletter .newsletter-form button:hover {
    background-color: var(--accent-color);
}

.footer-bottom-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
}

.footer-bottom-container .copyright {
    flex-basis: 100%;
    text-align: center;
    order: 2;
}

.footer-bottom-container .sub-links {
    flex-basis: 100%;
    text-align: center;
    order: 1;
}

.footer-bottom-container .sub-links a {
    color: var(--text-color);
    margin: 0 10px;
    font-size: 0.85rem;
}

/* --- 15. Back to Top Button --- */
#back-to-top {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 30px;
    z-index: 99;
    border: none;
    outline: none;
    background-color: var(--primary-color);
    color: white;
    cursor: pointer;
    padding: 0;
    border-radius: 50%;
    width: 45px;
    height: 45px;
    font-size: 1.3rem;
    transition: opacity 0.3s, background-color 0.3s;
}

#back-to-top:hover {
    background-color: var(--accent-color);
}

/* --- 16. Responsive Design --- */
@media (max-width: 992px) {
    h1 { font-size: 2.5rem; }
    h2 { font-size: 1.8rem; }
    #hero h1 { font-size: 3rem; }
    #hero p { font-size: 1.2rem; }

    .problem-grid,
    .how-it-works-grid,
    .audience-grid,
    .values-grid,
    .testimonials-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .footer-top-container {
        grid-template-columns: repeat(3, 1fr);
    }
    
    #footer-brand { grid-column: 1 / -1; text-align: center; }
    #footer-brand img { margin: 0 auto 20px auto; }
    #footer-newsletter { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background-color: var(--bg-color);
        flex-direction: column;
        align-items: center;
        padding-top: 50px;
        transition: left 0.4s ease-in-out;
    }
    
    .nav-links.active {
        left: 0;
    }

    .nav-links li {
        margin: 20px 0;
        font-size: 1.2rem;
    }

    .menu-toggle {
        display: block;
        margin-left: 20px;
    }
    
    .controls {
        margin-left: auto;
    }
    
    nav {
        justify-content: space-between;
        padding: 10px 5%;
    }

    #about .container {
        grid-template-columns: 1fr;
    }
    
    .about-image {
        margin-top: 30px;
    }

    .problem-grid,
    .how-it-works-grid,
    .audience-grid,
    .values-grid,
    .testimonials-grid,
    .swot-grid {
        grid-template-columns: 1fr;
    }
    
    .comparison-table {
        display: block;
        overflow-x: auto;
        white-space: nowrap;
    }
    
    .comparison-table thead, .comparison-table tbody, .comparison-table th, .comparison-table td, .comparison-table tr { 
        display: block; 
    }
    
    .comparison-table thead tr {
        position: absolute;
        top: -9999px;
        left: -9999px;
    }
    
    .comparison-table tr { 
        border: 1px solid var(--border-color);
        margin-bottom: 10px;
        border-radius: 10px;
    }
    
    .comparison-table td {
        border: none;
        position: relative;
        padding-left: 50%;
        text-align: right;
    }
    
    .comparison-table td::before {
        position: absolute;
        left: 6px;
        width: 45%;
        padding-right: 10px;
        white-space: nowrap;
        text-align: left;
        font-weight: 600;
        color: var(--primary-color);
    }

    .comparison-table td:nth-of-type(1)::before { content: attr(data-label); }
    .comparison-table td:nth-of-type(2)::before { content: attr(data-label); }
    .comparison-table td:nth-of-type(3)::before { content: attr(data-label); }
    .comparison-table td:nth-of-type(4)::before { content: attr(data-label); }

    .footer-top-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-col h4 {
        text-align: center;
    }
    
    .footer-bottom-container {
        flex-direction: column;
    }
    .footer-bottom-container .sub-links { order: 1; }
    .footer-bottom-container .copyright { order: 2; }
}

/* --- 17. Popular Groups Section --- */
#popular-groups {
    background-color: var(--bg-color);
}

.groups-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 40px;
}

.group-card {
    background-color: var(--card-bg);
    border-radius: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column; /* Sắp xếp các phần tử theo chiều dọc */
}

.group-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.group-card .card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border-color);
}

.group-card .tag {
    font-size: 0.8rem;
    font-weight: 600;
    padding: 5px 10px;
    border-radius: 20px;
    color: #fff;
}

.group-card .tag-study {
    background-color: #03A9F4; /* Blue */
}

.group-card .tag-sport {
    background-color: #F44336; /* Red */
}

.group-card .location {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-color);
    opacity: 0.7;
}

.group-card .card-body {
    padding: 20px;
    flex-grow: 1; /* Làm cho phần body co giãn để đẩy footer xuống */
}

.group-card .card-body h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: 10px;
}

.group-card .card-body p {
    font-size: 0.95rem;
    line-height: 1.5;
    margin-bottom: 0;
}

.group-card .card-footer {
    padding: 20px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap; /* Cho phép wrap trên mobile */
    gap: 15px;
}

.group-card .group-meta {
    font-size: 0.85rem;
}

.group-card .group-meta div {
    margin-bottom: 5px;
}

.group-card .group-meta strong {
    color: var(--text-color);
    opacity: 0.8;
}

.group-card .group-meta span {
    color: var(--primary-color);
    font-weight: 600;
}

.group-card .group-price {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
}

.group-card .btn-join {
    background-color: var(--primary-color);
    color: #fff;
    padding: 10px 20px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 0.9rem;
    text-align: center;
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.group-card .btn-join:hover {
    background-color: var(--accent-color);
    color: #333;
    transform: scale(1.05);
}

/* Responsive cho Group Cards */
@media (max-width: 992px) {
    .groups-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    .groups-grid {
        grid-template-columns: 1fr;
    }
    
    .group-card .card-footer {
        flex-direction: column; /* Xếp chồng các item trong footer */
        align-items: stretch; /* Kéo dãn các item */
    }
    
    .group-card .btn-join {
        width: 100%; /* Nút bấm chiếm toàn bộ chiều rộng */
    }
}

/* Thêm class này để ẩn/hiện khi lọc */
.group-card.hide {
    display: none;
}

/* CSS cho nút "Xem tất cả" */
.see-all-container {
    text-align: center;
    margin-top: 40px;
}

.see-all-btn {
    background-color: var(--accent-color);
    color: #333;
    padding: 12px 30px;
    border-radius: 50px;
    font-weight: 700;
    font-size: 1rem;
    text-transform: uppercase;
    transition: all 0.3s ease;
}

.see-all-btn:hover {
    background-color: var(--primary-color);
    color: #fff;
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

.see-all-btn i {
    margin-left: 8px;
    transition: transform 0.3s ease;
}

.see-all-btn:hover i {
    transform: translateX(5px);
}