/* الأساسيات */
@import url('https://fonts.googleapis.com/css2?family=Cairo:wght@300;400;500;600;700;800&display=swap');

:root {
    --primary-color: #16213e;
    --secondary-color: #4cc9f0;
    --accent-color: #ff6b6b;
    --text-color: #222831;
    --light-bg: #f6f8fc;
    --light-gray: #e6ecf5;
    --dark-gray: #8b97a8;
    --success-color: #22c55e;
    --warning-color: #f59e0b;
    --section-padding: 5rem 0;
    --transition-speed: 0.3s;
    --border-radius: 12px;
    --box-shadow: 0 12px 28px rgba(16, 24, 40, 0.07);
}

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

body {
    background-color: var(--light-bg);
    color: var(--text-color);
    line-height: 1.6;
}

/* نمط خاص بالصفحة الرئيسية فقط (يعتمد على ألوان النظام العامة) */



.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

section {
    padding: var(--section-padding);
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 1rem;
}

h2 {
    font-size: 2.2rem;
    position: relative;
    display: inline-block;
    margin-bottom: 2.5rem;
}

h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    right: 0;
    width: 50px;
    height: 4px;
    background-color: var(--secondary-color);
}

p {
    margin-bottom: 1.5rem;
}

img {
    max-width: 100%;
}

a {
    text-decoration: none;
    color: var(--secondary-color);
    transition: color var(--transition-speed);
}

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

/* القائمة الرئيسية */
.main-nav {
    background-color: var(--primary-color);
    padding: 0.8rem 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: all var(--transition-speed);
}

.nav-container {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

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

.logo img {
    height: 50px;
    margin-left: 10px;
}

.logo-text {
    color: white;
    font-size: 1.4rem;
    font-weight: 700;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    margin: 0 auto;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 0.8rem;
    border-radius: var(--border-radius);
    transition: all var(--transition-speed);
}

.nav-links a:hover,
.nav-links a.active {
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--secondary-color);
}

.mobile-nav-toggle {
    display: none;
    background: transparent;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
}

/* قسم الترحيب */
.hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, rgba(31, 42, 68, 0.92), rgba(58, 160, 255, 0.75)),
                url('images/picture_four.jpeg') center/cover;
    color: white;
    text-align: center;
    clip-path: polygon(0 0, 100% 0, 100% 85%, 0 100%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

.hero-badge {
    display: inline-block;
    padding: 0.35rem 0.75rem;
    border-radius: 999px;
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.3);
    margin-bottom: 1rem;
    font-weight: 600;
}

.gradient-text {
    background: linear-gradient(90deg, #fff, #d1f4ff);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.hero-shapes .shape {
    position: absolute;
    display: block;
    border-radius: 50%;
    opacity: 0.15;
    background: var(--secondary-color);
    filter: blur(2px);
}
.hero .s1 { width: 80px; height: 80px; top: 18%; right: 12%; animation: float 6s ease-in-out infinite; }
.hero .s2 { width: 60px; height: 60px; top: 30%; left: 14%; animation: float 7s ease-in-out infinite; }
.hero .s3 { width: 100px; height: 100px; bottom: 10%; left: 25%; animation: float 8s ease-in-out infinite; }

/* تأثير تمرير لطيف على الروابط في الهيرو */
.home .cta-buttons .btn { position: relative; overflow: hidden; }
.home .cta-buttons .btn::after { content: ''; position: absolute; inset: 0; background: radial-gradient(400px 120px at var(--x,50%) var(--y,50%), rgba(255,255,255,0.15), transparent 40%); opacity: 0; transition: opacity .25s ease; }
.home .cta-buttons .btn:hover::after { opacity: 1; }

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.professor-photo {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    margin-bottom: 2rem;
    border: 4px solid white;
    object-fit: cover;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.hero-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    line-height: 1.3;
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: rgba(255, 255, 255, 0.9);
}

/* الأزرار */
.cta-buttons {
    margin-top: 2rem;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.btn {
    padding: 0.8rem 2rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-speed);
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.btn i {
    margin-left: 8px;
}

.primary-btn {
    background-color: var(--secondary-color);
    color: white;
}

.primary-btn:hover {
    background-color: #2980b9;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.secondary-btn {
    background-color: transparent;
    border: 2px solid white;
    color: white;
}

.secondary-btn:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* قسم الميزات */
.features {
    padding: 5rem 0;
    background-color: white;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-card {
    text-align: center;
    padding: 2rem;
    border-radius: var(--border-radius);
    background-color: #fff;
    transition: all var(--transition-speed);
    box-shadow: var(--box-shadow);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* FAQ */
.faq { background: #fff; padding: 5rem 0; }
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { border: 1px solid #eee; border-radius: 12px; margin-bottom: 1rem; overflow: hidden; box-shadow: var(--box-shadow); }
.faq-question { width: 100%; text-align: right; padding: 1rem 1.25rem; background: #f9fbff; border: none; font-weight: 700; display: flex; align-items: center; justify-content: space-between; cursor: pointer; }
.faq-answer { padding: 0 1.25rem 1rem; display: none; color: #4b5563; }
.faq-item.open .faq-answer { display: block; }
.faq-item.open .faq-question i { transform: rotate(180deg); }

.feature-card i {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

/* بطاقات الدروس */
.latest-lessons {
    background-color: var(--light-bg);
    padding: 5rem 0;
    text-align: center;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.lessons-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.lesson-card {
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
    transition: all var(--transition-speed);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.lesson-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.lesson-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.lesson-content {
    padding: 1.5rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.lesson-content h3 {
    font-size: 1.3rem;
    margin-bottom: 0.8rem;
    line-height: 1.4;
}

.lesson-content p {
    color: #666;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.lesson-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1.5rem;
    color: var(--dark-gray);
    font-size: 0.9rem;
}

.lesson-meta span {
    display: flex;
    align-items: center;
}

.lesson-meta i {
    margin-left: 5px;
}

/* الأقسام الرئيسية */
.main-categories {
    background-color: white;
    padding: 5rem 0;
    text-align: center;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.category-card {
    background: #fff;
    padding: 2.5rem 2rem;
    border-radius: var(--border-radius);
    text-align: center;
    transition: all var(--transition-speed);
    box-shadow: var(--box-shadow);
    cursor: pointer;
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
    background: linear-gradient(135deg, var(--secondary-color), #6ee7ff);
    color: #0b1220;
}

.category-card:hover i {
    color: #0b1220;
}

.category-card i {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
    transition: all var(--transition-speed);
}

.category-card h3 {
    font-size: 1.5rem;
}

/* قسم الإحصائيات */
.statistics {
    background: radial-gradient(1200px 400px at 50% -20%, rgba(76, 201, 240, 0.25), transparent 60%),
                linear-gradient(135deg, rgba(22, 33, 62, 0.95), rgba(76, 201, 240, 0.6));
    padding: 5rem 0;
    color: white;
    text-align: center;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 2rem;
}

.stat-card {
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.12);
    backdrop-filter: blur(6px);
    padding: 2rem 1.5rem;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.stat-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 18px 36px rgba(0,0,0,0.2);
}

.stat-icon {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--secondary-color), #6ee7ff);
    color: #0b1220;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    margin-bottom: 1rem;
}

.stat-number {
    font-size: 2.4rem;
    font-weight: 800;
    color: #fff;
    letter-spacing: 0.5px;
}

.stat-text {
    font-size: 1rem;
    color: rgba(255,255,255,0.85);
    margin-top: 0.25rem;
}

/* قسم الشهادات */
.testimonials {
    background-color: var(--light-bg);
    padding: 5rem 0;
    text-align: center;
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.testimonial-card {
    background-color: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    position: relative;
}

.testimonial-card::before {
    content: '\201C';
    font-size: 4rem;
    position: absolute;
    top: 0.5rem;
    right: 1rem;
    color: #f0f0f0;
    z-index: 0;
}

.testimonial-text {
    position: relative;
    z-index: 1;
    margin-bottom: 1.5rem;
}

.testimonial-author {
    display: flex;
    align-items: center;
}

.testimonial-author img {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    margin-left: 1rem;
}

.author-info h4 {
    font-size: 1.1rem;
    margin-bottom: 0.3rem;
}

.author-info p {
    color: var(--dark-gray);
    margin-bottom: 0;
    font-size: 0.9rem;
}

/* قسم الاتصال */
.contact {
    background-color: white;
    padding: 5rem 0;
}

.contact-wrapper {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 3rem;
}

.contact-info h3 {
    margin-bottom: 1.5rem;
}

.contact-methods {
    margin-bottom: 2rem;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.contact-item i {
    min-width: 30px;
    margin-left: 10px;
    color: var(--secondary-color);
    font-size: 1.2rem;
}

.contact-form .form-group {
    margin-bottom: 1.5rem;
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: all var(--transition-speed);
}

.contact-form input:focus,
.contact-form textarea:focus {
    border-color: var(--secondary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.contact-form textarea {
    min-height: 150px;
    resize: vertical;
}

/* تذييل الصفحة */
footer {
    background-color: var(--primary-color);
    color: white;
    padding: 4rem 0 1rem;
}

/* بطاقات مقالات مختارة */
.articles-preview {
    background-color: #fff;
    padding: 5rem 0;
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.article-card {
    display: flex;
    flex-direction: column;
    background: #fff;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
    color: inherit;
}

.article-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 18px 36px rgba(16, 24, 40, 0.08);
}

.article-image {
    height: 180px;
    background-size: cover;
    background-position: center;
}

.article-content {
    padding: 1.5rem;
}

.article-content h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.article-content p {
    color: #5a6270;
    margin-bottom: 1rem;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--dark-gray);
    font-size: 0.9rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-section h3 {
    position: relative;
    margin-bottom: 1.5rem;
    display: inline-block;
}

.footer-section h3::after {
    content: '';
    position: absolute;
    bottom: -10px;
    right: 0;
    width: 30px;
    height: 3px;
    background-color: var(--secondary-color);
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    color: white;
    font-size: 1.2rem;
    transition: all var(--transition-speed);
}

.social-links a:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
}

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

.footer-section ul li {
    margin-bottom: 0.8rem;
}

.footer-section ul li a {
    color: #ddd;
    transition: all var(--transition-speed);
}

.footer-section ul li a:hover {
    color: var(--secondary-color);
    padding-right: 5px;
}

.newsletter input {
    width: 100%;
    padding: 0.8rem 1rem;
    border: none;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

/* الصفحات الداخلية */
.page-header {
    background: linear-gradient(rgba(44, 62, 80, 0.9), rgba(44, 62, 80, 0.9)),
                url('images/photo_10.png') center/cover;
    padding: 10rem 0 5rem;
    color: white;
    text-align: center;
    clip-path: polygon(0 0, 100% 0, 100% 85%, 0 100%);
}

.breadcrumbs {
    background-color: var(--light-gray);
    padding: 1rem 0;
    margin-bottom: 3rem;
}

.breadcrumbs-list {
    display: flex;
    list-style: none;
}

.breadcrumbs-list li {
    position: relative;
    padding-left: 1.5rem;
}

.breadcrumbs-list li:not(:last-child)::after {
    content: '/';
    position: absolute;
    left: 0.5rem;
    color: var(--dark-gray);
}

.breadcrumbs-list li:first-child {
    padding-left: 0;
}

.breadcrumbs-list a {
    color: var(--dark-gray);
}

.breadcrumbs-list li:last-child a {
    color: var(--text-color);
    font-weight: 600;
}

/* صفحة الدروس */
.lessons-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
}

.filter-button {
    padding: 0.5rem 1.5rem;
    background-color: var(--light-gray);
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-speed);
}

.filter-button.active,
.filter-button:hover {
    background-color: var(--secondary-color);
    color: white;
}

/* صفحة الأستاذ */
.about-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 3rem;
    align-items: flex-start;
}

.professor-info img {
    width: 100%;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
}

.professor-details {
    margin-bottom: 2rem;
}

.professor-details h3 {
    margin-bottom: 1rem;
}

.achievement-item {
    margin-bottom: 2rem;
}

.achievement-item h4 {
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

/* صفحة تفاصيل الدرس */
.lesson-details {
    background-color: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
    margin-bottom: 3rem;
}

.lesson-header {
    padding: 2rem;
    border-bottom: 1px solid #eee;
}

.lesson-meta-details {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    margin-top: 1.5rem;
}

.meta-item {
    display: flex;
    align-items: center;
}

.meta-item i {
    margin-left: 0.5rem;
    color: var(--secondary-color);
    font-size: 1.2rem;
}

.lesson-body {
    padding: 2rem;
}

.lesson-navigation {
    margin-top: 2rem;
    display: flex;
    justify-content: space-between;
}

.lesson-nav-btn {
    padding: 0.8rem 1.5rem;
    background-color: var(--light-gray);
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    transition: all var(--transition-speed);
}

.lesson-nav-btn:hover {
    background-color: var(--secondary-color);
    color: white;
}

.prev-lesson i {
    margin-left: 0.5rem;
}

.next-lesson i {
    margin-right: 0.5rem;
}

.related-lessons {
    margin-top: 4rem;
}

/* صفحة المنتدى */
.forum-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.new-topic-btn {
    padding: 0.7rem 1.5rem;
}

.forum-categories {
    margin-bottom: 3rem;
}

.category-item {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
}

.category-icon {
    min-width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--light-gray);
    border-radius: 50%;
    margin-left: 1.5rem;
}

.category-icon i {
    font-size: 1.5rem;
    color: var(--secondary-color);
}

.category-content h3 {
    margin-bottom: 0.5rem;
}

.topics-count {
    color: var(--dark-gray);
    font-size: 0.9rem;
}

.topic-list-item {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: flex-start;
}

.topic-info {
    flex-grow: 1;
}

.topic-title {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.topic-meta {
    display: flex;
    color: var(--dark-gray);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.topic-meta span {
    margin-left: 1rem;
    display: flex;
    align-items: center;
}

.topic-meta i {
    margin-left: 0.3rem;
}

.topic-author {
    display: flex;
    align-items: center;
}

.topic-author img {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    margin-left: 0.5rem;
}

.topic-stats {
    margin-right: 2rem;
    text-align: center;
    min-width: 100px;
}

.stats-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stats-text {
    color: var(--dark-gray);
    font-size: 0.9rem;
}

/* صفحة المكتبة والموارد */
.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.resource-card {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    transition: all var(--transition-speed);
    display: flex;
    flex-direction: column;
}

.resource-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.resource-card img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.resource-content {
    padding: 1.5rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.resource-type {
    background-color: var(--light-gray);
    padding: 0.3rem 0.8rem;
    border-radius: 30px;
    font-size: 0.8rem;
    display: inline-block;
    margin-bottom: 1rem;
}

.pdf .resource-type {
    background-color: rgba(231, 76, 60, 0.1);
    color: var(--accent-color);
}

.video .resource-type {
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--secondary-color);
}

.book .resource-type {
    background-color: rgba(46, 204, 113, 0.1);
    color: var(--success-color);
}

.resource-content h3 {
    font-size: 1.2rem;
    margin-bottom: 0.8rem;
}

.resource-content p {
    color: #666;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.resource-meta {
    display: flex;
    justify-content: space-between;
    color: var(--dark-gray);
    font-size: 0.9rem;
    margin-top: auto;
}

/* التجاوب مع مختلف الأجهزة */
@media (max-width: 991px) {
    .nav-links {
        position: fixed;
        top: 70px;
        right: -100%;
        width: 70%;
        height: calc(100vh - 70px);
        background-color: var(--primary-color);
        flex-direction: column;
        align-items: center;
        padding: 2rem 0;
        transition: all 0.4s ease;
    }

    .nav-links.active {
        right: 0;
    }

    .mobile-nav-toggle {
        display: block;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .professor-info {
        max-width: 400px;
        margin: 0 auto;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .section-title {
        margin-bottom: 2rem;
    }

    .lesson-meta-details {
        flex-direction: column;
        gap: 1rem;
    }

    .topic-list-item {
        flex-direction: column;
    }

    .topic-stats {
        display: flex;
        margin-right: 0;
        margin-top: 1rem;
        width: 100%;
        justify-content: space-around;
    }
}

@media (max-width: 576px) {
    .hero {
        padding: 7rem 0 3rem;
    }

    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }

    .cta-buttons .btn {
        width: 100%;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }
}

.testimonial-photo {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    object-fit: cover;
}