/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #000;
    background-color: #fff;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 500;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h2 {
    font-size: 2rem;
    font-weight: 500;
}

h3 {
    font-size: 1.75rem;
    font-weight: 500;
}

h4 {
    font-size: 1.25rem;
    font-weight: 500;
}

p {
    margin-bottom: 1rem;
}

a {
    color: #000;
    text-decoration: none;
    transition: opacity 0.2s ease;
}

a:hover {
    opacity: 0.7;
}

/* Header and Navigation */
header {
    position: sticky;
    top: 0;
    background-color: #fff;
    z-index: 100;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    padding: 1rem 0;
}

.header-container {
    max-width: 1500px;
    margin: 0 auto;
    padding: 0 6vw;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

@media (min-width: 768px) {
    .header-container {
        padding: 0 4vw;
    }
}

.logo {
    font-size: 1.25rem;
    font-weight: 500;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    align-items: center;
}

nav a {
    font-size: 1rem;
    font-weight: 400;
}

nav a.active {
    font-weight: 500;
}

.linkedin-link {
    display: inline-flex;
    align-items: center;
}

.linkedin-link img {
    width: 20px;
    height: 20px;
}

/* Skip to Content Link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: #000;
    color: #fff;
    padding: 8px;
    text-decoration: none;
    z-index: 1000;
}

.skip-link:focus {
    top: 0;
}

/* Main Content */
main {
    min-height: calc(100vh - 200px);
    padding: 4rem 0;
}

.container {
    max-width: 1500px;
    margin: 0 auto;
    padding: 0 6vw;
}

@media (min-width: 768px) {
    .container {
        padding: 0 4vw;
    }
}

.content-wrapper {
    max-width: 800px;
    margin: 0 auto;
}

/* Homepage Styles */
.homepage-hero {
    margin-bottom: 3rem;
}

.homepage-hero h3 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 400;
    line-height: 1.3;
    margin-bottom: 2rem;
}

.homepage-hero h3 strong {
    font-weight: 500;
}

.homepage-hero h3 em {
    font-style: italic;
}

.homepage-description {
    font-size: 1.125rem;
    line-height: 1.7;
    max-width: 700px;
}

/* Page Headers */
.page-header {
    margin-bottom: 3rem;
}

.page-header h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 500;
}

/* Sections */
.section {
    margin-bottom: 4rem;
}

.section h3 {
    margin-bottom: 1.5rem;
}

.section h4 {
    margin-bottom: 1rem;
    margin-top: 2rem;
}

.section h4:first-of-type {
    margin-top: 0;
}

/* Video Embed */
.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    height: 0;
    overflow: hidden;
    margin-bottom: 2rem;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* Teaching Areas Grid */
.teaching-areas {
    display: grid;
    gap: 2rem;
    margin-top: 2rem;
}

@media (min-width: 768px) {
    .teaching-areas {
        grid-template-columns: repeat(3, 1fr);
    }
}

.teaching-area {
    margin-bottom: 2rem;
}

.teaching-area h4 {
    margin-bottom: 1rem;
}

/* Testimonials */
.testimonials {
    display: grid;
    gap: 2rem;
    margin-top: 3rem;
}

@media (min-width: 768px) {
    .testimonials {
        grid-template-columns: repeat(3, 1fr);
    }
}

.testimonial {
    font-style: italic;
    margin-bottom: 1rem;
}

.testimonial-source {
    font-size: 0.875rem;
    font-style: normal;
    color: #666;
}

/* Articles List */
.articles-list {
    list-style: none;
    margin-top: 1rem;
}

.articles-list li {
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.articles-list li:last-child {
    border-bottom: none;
}

.articles-list a {
    font-weight: 500;
    display: block;
    margin-bottom: 0.25rem;
}

.articles-list .date {
    font-size: 0.875rem;
    color: #666;
}

/* Quote */
.quote {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 400;
    line-height: 1.4;
    margin: 3rem 0;
    text-align: center;
}

.quote em {
    font-style: italic;
}

/* Footer */
footer {
    border-top: 1px solid rgba(0, 0, 0, 0.1);
    padding: 3rem 0;
    margin-top: 4rem;
}

.footer-container {
    max-width: 1500px;
    margin: 0 auto;
    padding: 0 6vw;
    text-align: center;
}

@media (min-width: 768px) {
    .footer-container {
        padding: 0 4vw;
    }
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.footer-copyright {
    font-size: 0.875rem;
    color: #666;
}

.footer-social {
    margin: 0.5rem 0;
}

.footer-email {
    font-size: 1rem;
    font-weight: 500;
}

.footer-email a {
    font-weight: 500;
}

/* Responsive Typography */
@media (max-width: 767px) {
    body {
        font-size: 15px;
    }
    
    h2 {
        font-size: 1.75rem;
    }
    
    h3 {
        font-size: 1.5rem;
    }
    
    nav ul {
        gap: 1.5rem;
    }
    
    .homepage-description {
        font-size: 1rem;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mt-2 {
    margin-top: 2rem;
}

.mb-2 {
    margin-bottom: 2rem;
}