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

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    border-color: #e5e7eb;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: #ffffff;
    color: #1f2937;
    line-height: 1.6;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header & Navigation */
.header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: linear-gradient(to right, #0f172a, #1e293b, #5d2563);
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    transition: all 0.3s ease;
}

.logo:hover {
    color: #93c5fd;
}

.logo-icon {
    width: 2.5rem;
    height: 2.5rem;
    background: linear-gradient(135deg, #60a5fa, #a855f7);
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 1.125rem;
}

.logo-text {
    display: none;
}

.logo-text h1 {
    color: white;
    font-size: 0.875rem;
    font-weight: bold;
    line-height: 1;
}

.logo-text p {
    color: #cbd5e1;
    font-size: 0.75rem;
}

@media (min-width: 640px) {
    .logo-text {
        display: block;
    }
}

.nav-desktop {
    display: none;
    align-items: center;
    gap: 2rem;
}

@media (min-width: 1024px) {
    .nav-desktop {
        display: flex;
    }
}

.nav-link {
    color: #cbd5e1;
    text-decoration: none;
    transition: color 0.3s ease;
    font-weight: 500;
    font-size: 0.875rem;
}

.nav-link:hover {
    color: #93c5fd;
}

.register-btn {
    display: none;
    padding: 0.5rem 1.5rem;
    background: linear-gradient(to right, #3b82f6, #a855f7);
    color: white;
    font-weight: 600;
    border-radius: 0.5rem;
    text-decoration: none;
    transition: all 0.3s ease;
}

.register-btn:hover {
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
}

@media (min-width: 640px) {
    .register-btn {
        display: inline-block;
    }
}

.menu-btn {
    display: flex;
    flex-direction: column;
    gap: 0.375rem;
    background: none;
    border: none;
    cursor: pointer;
    z-index: 51;
}

@media (min-width: 1024px) {
    .menu-btn {
        display: none;
    }
}

.menu-btn span {
    width: 1.5rem;
    height: 0.25rem;
    background-color: white;
    border-radius: 0.125rem;
    transition: all 0.3s ease;
}

.menu-btn.active span:nth-child(1) {
    transform: rotate(45deg) translate(0.5rem, 0.75rem);
}

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

.menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg) translate(0.5rem, -0.75rem);
}

.nav-mobile {
    display: none;
    flex-direction: column;
    gap: 0.5rem;
    padding-bottom: 1rem;
}

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

.nav-link-mobile {
    color: #cbd5e1;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 0.75rem;
    border-radius: 0.375rem;
    transition: all 0.3s ease;
}

.nav-link-mobile:hover {
    background-color: rgba(30, 41, 59, 0.7);
    color: #93c5fd;
}

.register-btn-mobile {
    margin-top: 0.5rem;
    padding: 0.5rem 1rem;
    background: linear-gradient(to right, #3b82f6, #a855f7);
    color: white;
    font-weight: 600;
    border-radius: 0.5rem;
    text-decoration: none;
    text-align: center;
    transition: all 0.3s ease;
}

.register-btn-mobile:hover {
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
}

/* Hero Section */
.hero {
    background: linear-gradient(to bottom right, #0f172a, #1e293b, #581c87);
    color: white;
    padding: 5rem 0;
}

@media (min-width: 768px) {
    .hero {
        padding: 8rem 0;
    }
}

.hero-content {
    max-width: 56rem;
    margin: 0 auto;
    text-align: center;
}

.hero-title {
    font-size: 2.25rem;
    font-weight: bold;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

@media (min-width: 768px) {
    .hero-title {
        font-size: 3.75rem;
    }
}

.hero-subtitle {
    font-size: 1.25rem;
    font-weight: 300;
    margin-bottom: 2rem;
    color: #e2e8f0;
}

@media (min-width: 768px) {
    .hero-subtitle {
        font-size: 1.5rem;
    }
}

.hero-code {
    font-size: 1.125rem;
    color: #cbd5e1;
    margin-bottom: 2rem;
}

.hero-buttons {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 3rem;
}

@media (min-width: 640px) {
    .hero-buttons {
        flex-direction: row;
    }
}

.btn {
    padding: 0.75rem 2rem;
    font-weight: bold;
    border-radius: 0.5rem;
    text-decoration: none;
    transition: all 0.3s ease;
    display: inline-block;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(to right, #3b82f6, #a855f7);
    color: white;
}

.btn-primary:hover {
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
}

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

.btn-secondary:hover {
    background-color: white;
    color: #0f172a;
}

.btn.full-width {
    width: 100%;
}

.hero-details {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-top: 3rem;
}

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

.detail-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 0.5rem;
    padding: 1rem;
}

.detail-icon {
    width: 1.5rem;
    height: 1.5rem;
    margin: 0 auto 0.5rem;
    display: block;
}

.detail-card:nth-child(1) .detail-icon {
    color: #60a5fa;
}

.detail-card:nth-child(2) .detail-icon {
    color: #c084fc;
}

.detail-card:nth-child(3) .detail-icon {
    color: #4ade80;
}

/* Sections */
main {
    flex: 1;
}

.about-section {
    padding: 2rem 0;
}

@media (min-width: 768px) {
    .about-section {
        padding: 2rem 0;
    }
}

.department-section {
    padding: 2rem 0;
    background-color: #f8fafc;
}

@media (min-width: 768px) {
    .department-section {
        padding: 2rem 0;
    }
}

.conference-section {
    padding: 2rem 0;
    background: linear-gradient(to right, #f0f9ff, #faf5ff);
}

@media (min-width: 768px) {
    .conference-section {
        padding: 2rem 0;
    }
}

.dates-section {
    padding: 2rem 0;
    background-color: #f8fafc;
}

@media (min-width: 768px) {
    .dates-section {
        padding: 2rem 0;
    }
}

.call-for-papers-section {
    padding: 2rem 0;
}

@media (min-width: 768px) {
    .call-for-papers-section {
        padding: 2rem 0;
    }
}

.committee-section {
    padding: 2rem 0;
    background-color: #f8fafc;
}

@media (min-width: 768px) {
    .committee-section {
        padding: 2rem 0;
    }
}

.registration-section {
    padding: 2rem 0;
}

@media (min-width: 768px) {
    .registration-section {
        padding: 2rem 0;
    }
}

.contact-section {
    padding: 2rem 0;
    background-color: #f8fafc;
}

@media (min-width: 768px) {
    .contact-section {
        padding: 2rem 0;
    }
}

/* Typography */
.section-title {
    font-size: 1.875rem;
    font-weight: bold;
    text-align: center;
    margin-bottom: 3rem;
}

@media (min-width: 768px) {
    .section-title {
        font-size: 2.25rem;
    }
}

.subsection-title {
    font-size: 1.5rem;
    font-weight: bold;
    color: #111827;
    margin-bottom: 1.5rem;
    margin-top: 2rem;
}

.subsection-title:first-child {
    margin-top: 0;
}

.content-box {
    max-width: 56rem;
    margin: 0 auto;
}

.content-box p {
    color: #374151;
    line-height: 1.75;
    margin-bottom: 1.5rem;
}

/* Dates Grid */
.dates-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 48rem;
    margin: 0 auto;
}

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

.date-card {
    background-color: white;
    border-left: 4px solid #3b82f6;
    border-radius: 0.5rem;
    padding: 1.5rem;
    text-align: center;
}

.date-label {
    font-size: 0.875rem;
    color: #6b7280;
    margin-bottom: 0.5rem;
}

.date-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: #111827;
}

/* Guidelines & Review */
.guidelines-box {
    background-color: #f0f9ff;
    border-left: 4px solid #3b82f6;
    border-radius: 0.5rem;
    padding: 2rem;
    margin-bottom: 4rem;
    max-width: 56rem;
    margin-left: auto;
    margin-right: auto;
}

.guidelines-list {
    list-style: none;
    space-y: 1rem;
}

.guidelines-list li {
    gap: 0.75rem;
    margin-bottom: 1rem;
    color: #374151;
}

.guidelines-list li::before {
    content: '•';
    color: #3b82f6;
    font-weight: bold;
    flex-shrink: 0;
}

.submit-info {
    margin-top: 1.5rem;
    font-size: 0.875rem;
    color: #4b5563;
    font-weight: 600;
}

.submit-info a {
    color: #2563eb;
}

.submit-info a:hover {
    color: #1d4ed8;
}

.timeline-title,
.tracks-title,
.conduct-title,
.benefits-title {
    max-width: 56rem;
    margin-left: auto;
    margin-right: auto;
}

.review-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 80rem;
    margin: 0 auto 4rem;
}

@media (min-width: 768px) {
    .review-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.review-card {
    background: linear-gradient(135deg, #f3f4f6, #ede9fe);
    border: 1px solid #ddd6fe;
    border-radius: 0.5rem;
    padding: 1.5rem;
}

.review-card h4 {
    font-weight: bold;
    color: #111827;
    margin-bottom: 0.5rem;
}

.review-card p {
    font-size: 0.875rem;
    color: #374151;
}

/* Research Tracks */
.tracks-container {
    max-width: 56rem;
    margin: 0 auto 4rem;
    space-y: 1rem;
}

.track-item {
    background-color: white;
    border: 1px solid #e5e7eb;
    border-radius: 0.5rem;
    overflow: hidden;
    margin-bottom: 1rem;
}

.track-button {
    width: 100%;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: transparent;
    border: none;
    cursor: pointer;
    font-weight: bold;
    font-size: 1.125rem;
    color: #111827;
    transition: background-color 0.3s ease;
    text-align: left;
}

.track-button:hover {
    background-color: #f9fafb;
}

.track-icon {
    width: 1.25rem;
    height: 1.25rem;
    color: #6b7280;
    transition: transform 0.3s ease;
}

.track-button.active + .track-topics {
    display: block;
}

.track-button.active .track-icon {
    transform: rotate(180deg);
}

.track-topics {
    display: none;
    padding: 1rem 1.5rem;
    border-top: 1px solid #e5e7eb;
    background-color: #f9fafb;
}

.track-topics ol {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
}

@media (min-width: 768px) {
    .track-topics ol {
        grid-template-columns: repeat(2, 1fr);
    }
}

.track-topics li {
    font-size: 0.875rem;
    color: #374151;
    display: flex;
    gap: 0.75rem;
}

.track-topics li strong {
    color: #2563eb;
    flex-shrink: 0;
}

/* Code of Conduct */
.conduct-box {
    background: linear-gradient(135deg, #fef3c7, #fed7aa);
    border-left: 4px solid #f97316;
    border-radius: 0.5rem;
    padding: 2rem;
    max-width: 56rem;
    margin: 0 auto 4rem;
}

.conduct-list {
    list-style: none;
    margin-top: 1.5rem;
    space-y: 1rem;
}

.conduct-list li {
    display: flex;
    gap: 0.75rem;
    color: #374151;
    margin-bottom: 1rem;
}

.conduct-list li::before {
    content: '•';
    color: #ea580c;
    font-weight: bold;
    flex-shrink: 0;
}

/* Benefits Grid */
.benefits-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    max-width: 80rem;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .benefits-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.benefit-card {
    background-color: white;
    border-top: 4px solid #3b82f6;
    border-radius: 0.5rem;
    padding: 1.5rem;
    transition: box-shadow 0.3s ease;
}

.benefit-card:hover {
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.benefit-card h4 {
    font-weight: bold;
    color: #111827;
    margin-bottom: 0.75rem;
}

.benefit-card p {
    font-size: 0.875rem;
    color: #374151;
}

/* Committee */
.patrons-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 80rem;
    margin: 0 auto 4rem;
}

@media (min-width: 768px) {
    .patrons-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.patron-card {
    background: linear-gradient(135deg, #dbeafe, #f0e7fe);
    border-left: 4px solid #2563eb;
    border-radius: 0.5rem;
    padding: 1.5rem;
    font-weight: 600;
    color: #111827;
    transition: box-shadow 0.3s ease;
}

.patron-card:hover {
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
}

.leadership-container {
    max-width: 48rem;
    margin: 0 auto 4rem;
}

.leadership-card {
    border-top: 4px solid #3b82f6;
    border-radius: 0.5rem;
    padding: 2rem;
    margin-bottom: 2rem;
    background-color: white;
    border: 1px solid #e5e7eb;
}

.leadership-card.chairperson {
    background: linear-gradient(135deg, #dbeafe, #dbeafe);
}

.leadership-card.convenors {
    background: linear-gradient(135deg, #dbeafe, #f0e7fe);
}

.leadership-card.co-convenors {
    background: linear-gradient(135deg, #dcfce7, #f0e7fe);
}

.leadership-card h4 {
    font-size: 1.25rem;
    font-weight: bold;
    color: #111827;
    margin-bottom: 1rem;
}

.leadership-name {
    font-weight: 600;
    color: #111827;
    margin-bottom: 0.25rem;
}

.convenor-item {
    margin-bottom: 1.5rem;
}

.convenor-item p {
    font-size: 0.875rem;
    color: #374151;
    margin: 0.25rem 0;
}

.organizing-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 80rem;
    margin: 0 auto 4rem;
}

@media (min-width: 768px) {
    .organizing-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .organizing-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.org-card {
    background: linear-gradient(135deg, #f0f9ff, #f0e7fe);
    border-left: 4px solid #4f46e5;
    border-radius: 0.5rem;
    padding: 1.5rem;
    font-weight: 600;
    color: #111827;
    transition: box-shadow 0.3s ease;
}

.org-card:hover {
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
}

.advisory-container {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    max-width: 80rem;
    margin: 0 auto;
}

.advisory-card {
    background-color: white;
    border-left: 4px solid #a855f7;
    border-radius: 0.5rem;
    padding: 1.5rem;
    transition: box-shadow 0.3s ease;
}

.advisory-card:hover {
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
}

.advisory-name {
    font-weight: bold;
    color: #111827;
    margin-bottom: 0.5rem;
}

.advisory-card p {
    font-size: 0.875rem;
    color: #374151;
}

/* Registration */
.registration-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 3rem;
    max-width: 80rem;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .registration-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.registration-box {
    background-color: white;
    border: 1px solid #e5e7eb;
    border-radius: 0.5rem;
    padding: 1.5rem;
}

.registration-box h3 {
    font-size: 1.25rem;
    font-weight: bold;
    color: #111827;
    margin-bottom: 1.5rem;
}

.fee-list {
    space-y: 1rem;
    margin-bottom: 1.5rem;
}

.fee-item {
    display: flex;
    justify-content: space-between;
    background-color: white;
    padding: 1rem;
    border-radius: 0.5rem;
    border: 1px solid #e5e7eb;
    margin-bottom: 1rem;
}

.fee-amount {
    font-weight: bold;
    color: #111827;
}

.fee-note {
    font-size: 0.875rem;
    color: #4b5563;
    background-color: #f0f9ff;
    padding: 1rem;
    border-radius: 0.5rem;
}

.payment-details {
    space-y: 1rem;
    margin-bottom: 1.5rem;
}

.payment-item {
    margin-bottom: 1rem;
}

.payment-item .label {
    font-size: 0.875rem;
    color: #4b5563;
    font-weight: 600;
}

.payment-item .value {
    color: #111827;
    margin-top: 0.25rem;
}

.font-mono {
    font-family: 'Courier New', monospace;
}

/* Contact Grid */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    max-width: 48rem;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .contact-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.contact-card {
    background: linear-gradient(135deg, #f0f9ff, #faf5ff);
    border-radius: 0.5rem;
    padding: 2rem;
}

.contact-card h3 {
    font-weight: bold;
    color: #111827;
    margin-bottom: 0.75rem;
    font-size: 1.125rem;
}

.contact-role {
    font-size: 0.875rem;
    color: #4b5563;
    margin-bottom: 1rem;
}

.contact-info {
    space-y: 0.75rem;
}

.contact-info p {
    font-size: 0.875rem;
    color: #374151;
    margin-bottom: 0.75rem;
}

.contact-info a {
    color: #2563eb;
    text-decoration: none;
}

.contact-info a:hover {
    color: #1d4ed8;
}

/* Footer */
.footer {
    background-color: #0f172a;
    color: #cbd5e1;
    padding: 3rem 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

@media (min-width: 768px) {
    .footer-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.footer-section h3 {
    color: white;
    font-weight: bold;
    margin-bottom: 1rem;
}

.footer-section h4 {
    color: white;
    font-weight: bold;
    margin-bottom: 1rem;
    font-size: 0.875rem;
}

.footer-section p {
    font-size: 0.875rem;
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

.footer-section ul {
    list-style: none;
    space-y: 0.5rem;
}

.footer-section li {
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: #93c5fd;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: #60a5fa;
}

.footer-section li p {
    font-size: 0.75rem;
    color: #94a3b8;
    margin: 0.25rem 0 0 0;
}

.footer-bottom {
    border-top: 1px solid rgba(203, 213, 225, 0.2);
    padding-top: 2rem;
    text-align: center;
    font-size: 0.875rem;
}

.footer-bottom p {
    margin: 0.5rem 0;
}

/* Responsive adjustments */
@media (max-width: 640px) {
    .hero-title {
        font-size: 1.875rem;
    }

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

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

    .subsection-title {
        font-size: 1.25rem;
    }

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

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

/* Utility Classes */
.space-y-4 > * + * {
    margin-top: 1rem;
}

.space-y-6 > * + * {
    margin-top: 1.5rem;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.3s ease-out;
}

.slide-down {
    animation: slideDown 0.3s ease-out;
}

/* Smooth transitions */
a, button {
    transition: all 0.3s ease;
}