/* ===========================
   CSS Variables - Green Theme
   =========================== */
:root {
    --primary-green: #1e4620;
    --secondary-green: #2d5f2e;
    --light-green: #4a8b4d;
    --lighter-green: #8bc38e;
    --accent-green: #3d7340;
    --bg-light: #fafdfb;
    --bg-white: #ffffff;
    --text-dark: #1a1f1a;
    --text-medium: #3a4a3a;
    --text-light: #5f6f5f;
    --border-color: #e5f2e6;
    --shadow: rgba(30, 70, 32, 0.04);
    --shadow-medium: rgba(30, 70, 32, 0.08);
    --shadow-large: rgba(30, 70, 32, 0.12);

    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --border-radius: 8px;
    --card-radius: 12px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    color: var(--text-dark);
    background-color: var(--bg-light);
    line-height: 1.7;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-dark);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.5rem; }

p {
    margin-bottom: 1rem;
    color: var(--text-medium);
}

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

/* ===========================
   Container & Layout
   =========================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 1rem;
    color: var(--text-dark);
    font-size: 2.25rem;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

/* ===========================
   Navigation
   =========================== */
.navbar {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    box-shadow: 0 1px 0 var(--border-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1.25rem 0;
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-green);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2.5rem;
    align-items: center;
}

.nav-link {
    color: var(--text-medium);
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--secondary-green);
    transition: width 0.3s ease;
}

.nav-link:hover {
    color: var(--primary-green);
}

.nav-link:hover::after {
    width: 100%;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--primary-green);
    border-radius: 2px;
    transition: var(--transition);
}

/* ===========================
   Hero Section
   =========================== */
.hero {
    background: linear-gradient(135deg, var(--bg-white) 0%, var(--bg-light) 100%);
    padding: 7rem 0 5rem;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

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

.hero-title {
    font-size: 3.5rem;
    color: var(--text-dark);
    margin-bottom: 0.75rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-medium);
    margin-bottom: 0.75rem;
    font-weight: 400;
}

.hero-description {
    font-size: 1.05rem;
    color: var(--text-light);
    margin-bottom: 2.5rem;
    line-height: 1.6;
    letter-spacing: 0.02em;
}

.hero-cta {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ===========================
   Buttons
   =========================== */
.btn {
    padding: 0.875rem 2rem;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    display: inline-block;
    border: 2px solid transparent;
    letter-spacing: 0.3px;
}

.btn-primary {
    background: var(--primary-green);
    color: white;
    border-color: var(--primary-green);
    box-shadow: 0 2px 8px var(--shadow);
}

.btn-primary:hover {
    background: var(--secondary-green);
    border-color: var(--secondary-green);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px var(--shadow-medium);
}

.btn-outline {
    background: transparent;
    color: var(--primary-green);
    border-color: var(--primary-green);
}

.btn-outline:hover {
    background: var(--primary-green);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 4px 16px var(--shadow-medium);
}

/* ===========================
   About Section
   =========================== */
.about-section {
    background: var(--bg-white);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.9;
    margin-bottom: 1.5rem;
    color: var(--text-medium);
}

/* ===========================
   Experience Section
   =========================== */
.experience-section {
    background: var(--bg-light);
}

.experience-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 3rem;
    margin-top: 3rem;
}

.experience-column {
    background: var(--bg-white);
    padding: 2.5rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.column-title {
    color: var(--primary-green);
    font-size: 1.5rem;
    margin-bottom: 2rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--light-green);
}

.experience-item {
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

.experience-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.experience-item h4 {
    color: var(--primary-green);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.experience-item .org-name {
    color: var(--text-medium);
    font-weight: 600;
    font-size: 1.05rem;
    margin-bottom: 0.25rem;
}

.experience-item .duration {
    color: var(--text-light);
    font-size: 0.95rem;
    font-style: italic;
    margin-bottom: 0.5rem;
}

.experience-item .highlight {
    color: var(--secondary-green);
    font-weight: 600;
    font-size: 1rem;
}

.experience-item ul {
    margin-top: 0.75rem;
    padding-left: 1.5rem;
}

.experience-item ul li {
    color: var(--text-medium);
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

/* ===========================
   Expertise Section
   =========================== */
.expertise-section {
    background: var(--bg-white);
}

.expertise-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    margin-top: 3rem;
}

.expertise-card {
    background: var(--bg-white);
    padding: 2.5rem 2rem;
    border-radius: var(--card-radius);
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px var(--shadow);
}

.expertise-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--shadow-medium);
    border-color: var(--secondary-green);
}

.expertise-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.expertise-card h3 {
    color: var(--primary-green);
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

.expertise-card p {
    color: var(--text-light);
    font-size: 1rem;
    line-height: 1.7;
}

/* ===========================
   Writings Preview Section
   =========================== */
.writings-preview-section {
    background: var(--bg-white);
}

.writings-preview {
    max-width: 800px;
    margin: 0 auto 3rem;
    padding: 3rem;
    background: var(--bg-light);
    border-radius: 12px;
    border-left: 4px solid var(--secondary-green);
}

.coming-soon {
    font-size: 1.1rem;
    color: var(--text-medium);
    text-align: center;
    font-style: italic;
}

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

/* ===========================
   Contact Section
   =========================== */
.contact-section {
    background: linear-gradient(135deg, var(--bg-light) 0%, #e8f3e0 100%);
}

.contact-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.contact-intro {
    font-size: 1.2rem;
    margin-bottom: 2.5rem;
    color: var(--text-medium);
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    background: var(--bg-white);
    border-radius: 10px;
    color: var(--primary-green);
    font-weight: 600;
    transition: var(--transition);
    border: 2px solid var(--border-color);
}

.contact-link:hover {
    background: var(--primary-green);
    color: white;
    border-color: var(--primary-green);
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--shadow-medium);
}

.contact-link .icon {
    width: 24px;
    height: 24px;
}

/* ===========================
   Footer
   =========================== */
.footer {
    background: var(--bg-white);
    border-top: 1px solid var(--border-color);
    color: var(--text-light);
    text-align: center;
    padding: 2rem 0;
}

.footer p {
    color: var(--text-light);
    margin-bottom: 0;
    font-size: 0.9rem;
}

/* ===========================
   Writings Page Styles
   =========================== */
.writings-header {
    background: linear-gradient(135deg, var(--bg-light) 0%, #e8f3e0 100%);
    padding: 5rem 0 3rem;
    text-align: center;
}

.writings-header h1 {
    color: var(--primary-green);
    margin-bottom: 1rem;
}

.writings-intro {
    max-width: 700px;
    margin: 0 auto;
    font-size: 1.1rem;
    color: var(--text-medium);
}

.writings-container {
    background: var(--bg-white);
    padding: 4rem 0;
}

.category-section {
    margin-bottom: 4rem;
}

.category-title {
    color: var(--primary-green);
    font-size: 2rem;
    margin-bottom: 0.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 3px solid var(--light-green);
}

.category-description {
    color: var(--text-light);
    margin-bottom: 2rem;
    font-size: 1rem;
}

.articles-grid {
    display: grid;
    gap: 2rem;
}

.article-card {
    background: var(--bg-light);
    border-radius: 12px;
    padding: 2rem;
    transition: var(--transition);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--secondary-green);
}

.article-card:hover {
    transform: translateX(8px);
    box-shadow: 0 8px 24px var(--shadow-medium);
    border-left-color: var(--light-green);
}

.article-meta {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    color: var(--text-light);
}

.article-date, .article-type {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.article-card h3 {
    color: var(--primary-green);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.article-card h3 a {
    color: var(--primary-green);
}

.article-card h3 a:hover {
    color: var(--secondary-green);
}

.article-excerpt {
    color: var(--text-medium);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.article-link {
    color: var(--secondary-green);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.article-link:hover {
    color: var(--light-green);
}

.placeholder-message {
    text-align: center;
    padding: 3rem;
    background: var(--bg-light);
    border-radius: 12px;
    color: var(--text-light);
    font-style: italic;
    border: 2px dashed var(--border-color);
}

/* ===========================
   Responsive Design
   =========================== */

/* Large Desktop (1440px+) */
@media (min-width: 1440px) {
    .container {
        max-width: 1400px;
    }

    .hero-title {
        font-size: 4.5rem;
    }

    .section-title {
        font-size: 3rem;
    }
}

/* Tablet Landscape and Small Desktop (1024px - 1199px) */
@media (max-width: 1199px) {
    .container {
        max-width: 1000px;
    }

    .expertise-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 1.5rem;
    }
}

/* Tablet Portrait (768px - 1023px) */
@media (max-width: 1023px) {
    .container {
        padding: 0 2rem;
    }

    .hero {
        padding: 6rem 0 4rem;
    }

    .hero-title {
        font-size: 3rem;
    }

    .hero-subtitle {
        font-size: 1.3rem;
    }

    .nav-menu {
        gap: 1.5rem;
    }

    .nav-link {
        font-size: 0.9rem;
    }

    .expertise-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
}

/* Mobile Landscape and Tablet Portrait (768px - 991px) */
@media (max-width: 991px) {
    .navbar .container {
        padding: 0 1.5rem;
    }

    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-white);
        flex-direction: column;
        padding: 2rem;
        box-shadow: 0 8px 16px var(--shadow-medium);
        gap: 0;
        display: none;
        border-top: 1px solid var(--border-color);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-menu li {
        width: 100%;
        padding: 0.75rem 0;
        border-bottom: 1px solid var(--border-color);
    }

    .nav-menu li:last-child {
        border-bottom: none;
    }

    .nav-link {
        display: block;
        padding: 0.5rem 0;
        font-size: 1.1rem;
    }

    .nav-link::after {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
        z-index: 1001;
    }

    .mobile-menu-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .mobile-menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .mobile-menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }

    .expertise-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .experience-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .experience-column {
        padding: 2rem;
    }

    .contact-links {
        flex-direction: column;
    }

    .contact-link {
        width: 100%;
        justify-content: center;
    }
}

/* Mobile Portrait (up to 767px) */
@media (max-width: 767px) {
    .container {
        padding: 0 1.25rem;
    }

    .navbar {
        padding: 0.75rem 0;
    }

    .nav-brand {
        font-size: 1.25rem;
    }

    .hero {
        padding: 5rem 0 3rem;
    }

    .hero-title {
        font-size: 2.5rem;
        margin-bottom: 0.75rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
        margin-bottom: 0.75rem;
    }

    .hero-description {
        font-size: 1rem;
        margin-bottom: 2rem;
    }

    .hero-cta {
        flex-direction: column;
        gap: 1rem;
    }

    .btn {
        width: 100%;
        text-align: center;
    }

    .section {
        padding: 3rem 0;
    }

    .section-title {
        font-size: 2rem;
        margin-bottom: 0.75rem;
    }

    .section-subtitle {
        font-size: 1rem;
        margin-bottom: 2rem;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }

    .about-text p {
        font-size: 1rem;
    }

    .experience-item h4 {
        font-size: 1.1rem;
    }

    .experience-item .org-name {
        font-size: 1rem;
    }

    .expertise-card {
        padding: 2rem 1.5rem;
    }

    .expertise-card h3 {
        font-size: 1.3rem;
    }

    .expertise-icon {
        font-size: 2.5rem;
    }

    .writings-preview {
        padding: 2rem 1.5rem;
    }

    .article-card {
        padding: 1.5rem;
    }

    .article-card h3 {
        font-size: 1.3rem;
    }

    .article-meta {
        flex-direction: column;
        gap: 0.5rem;
        font-size: 0.85rem;
    }

    .contact-intro {
        font-size: 1.1rem;
    }

    .footer {
        padding: 2rem 0;
    }

    .category-title {
        font-size: 1.75rem;
    }

    .writings-header {
        padding: 4rem 0 2.5rem;
    }

    .writings-header h1 {
        font-size: 2.25rem;
    }

    .writings-intro {
        font-size: 1rem;
    }
}

/* Small Mobile (up to 480px) */
@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .navbar {
        padding: 0.6rem 0;
    }

    .nav-brand {
        font-size: 1.1rem;
    }

    .mobile-menu-toggle span {
        width: 22px;
        height: 2.5px;
    }

    .hero {
        padding: 4rem 0 2.5rem;
    }

    .hero-title {
        font-size: 1.875rem;
        line-height: 1.2;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-description {
        font-size: 0.95rem;
        line-height: 1.6;
    }

    .section {
        padding: 2.5rem 0;
    }

    .section-title {
        font-size: 1.625rem;
    }

    .section-subtitle {
        font-size: 0.95rem;
    }

    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.9rem;
    }

    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.15rem; }

    .about-text p {
        font-size: 0.95rem;
        line-height: 1.7;
    }

    .expertise-card {
        padding: 1.75rem 1.25rem;
    }

    .expertise-card h3 {
        font-size: 1.2rem;
    }

    .expertise-card p {
        font-size: 0.95rem;
    }

    .expertise-icon {
        font-size: 2.25rem;
        margin-bottom: 1rem;
    }

    .writings-preview {
        padding: 1.5rem 1rem;
    }

    .coming-soon,
    .placeholder-message {
        font-size: 0.95rem;
        padding: 2rem 1rem;
    }

    .article-card {
        padding: 1.25rem;
    }

    .article-card h3 {
        font-size: 1.2rem;
        margin-bottom: 0.75rem;
    }

    .article-excerpt {
        font-size: 0.95rem;
        line-height: 1.7;
    }

    .contact-intro {
        font-size: 1rem;
    }

    .contact-link {
        padding: 0.875rem 1.5rem;
        font-size: 0.95rem;
    }

    .footer {
        padding: 1.75rem 0;
        font-size: 0.9rem;
    }

    .footer-tagline {
        font-size: 0.85rem;
    }

    .category-title {
        font-size: 1.5rem;
        padding-bottom: 0.5rem;
    }

    .category-description {
        font-size: 0.95rem;
        margin-bottom: 1.5rem;
    }

    .writings-header {
        padding: 3.5rem 0 2rem;
    }

    .writings-header h1 {
        font-size: 1.875rem;
    }

    .writings-intro {
        font-size: 0.95rem;
        padding: 0 0.5rem;
    }

    .nav-menu {
        padding: 1.5rem;
    }

    .nav-menu li {
        padding: 0.6rem 0;
    }

    .nav-link {
        font-size: 1rem;
    }
}

/* Extra Small Mobile (up to 360px) */
@media (max-width: 360px) {
    .hero-title {
        font-size: 1.625rem;
    }

    .hero-subtitle {
        font-size: 0.95rem;
    }

    .hero-description {
        font-size: 0.9rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .btn {
        padding: 0.7rem 1.25rem;
        font-size: 0.875rem;
    }

    .expertise-card {
        padding: 1.5rem 1rem;
    }

    .contact-link {
        padding: 0.75rem 1.25rem;
        font-size: 0.9rem;
    }
}