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

body {
    font-family: 'Noto Sans JP', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header Styles */
.header {
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
}

.logo-image {
    height: 60px;
    width: auto;
    max-width: 450px;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 25px;
}

.nav-link {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
    font-size: 15px;
}

.nav-link:hover {
    color: #1e3a8a;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: #1e3a8a;
    transition: width 0.3s ease;
}

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

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: #333;
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    position: relative;
    height: 60vh;
    min-height: 400px;
    max-height: 600px;
    margin-top: 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    background: url("../images/hero_mark.svg") no-repeat right center #F2F2FA;
    background-size: auto 100%;
}

.hero-image {
    width: auto;
    height: 100%;
}


/* Section Styles */
.section-title {
    font-size: 32px;
    font-weight: 700;
    color: #1e3a8a;
    text-align: center;
    margin-bottom: 50px;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background-color: #3b82f6;
}

/* Message Section */
.message-section {
    padding: 80px 0;
    background-color: rgba(255, 255, 255, 0.95);
    background-image: url('../images/background-pattern.svg');
    background-attachment: fixed;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.message-content {
    display: flex;
    gap: 40px;
    align-items: flex-start;
}

.professor-image {
    flex-shrink: 0;
}

.professor-photo {
    width: 200px;
    height: 200px;
    object-fit: cover;
    border-radius: 50%;
    display: block;
    margin: auto;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.message-text {
    flex: 1;
}

.message-placeholder {
    font-size: 16px;
    color: #666;
    margin-bottom: 20px;
    line-height: 1.8;
}

.related-link:hover {
    color: #3b82f6;
}

/* Research Section */
.research-section {
    padding: 80px 0;
    background-color: #f8fafc;
}

.research-item {
    display: flex;
    gap: 40px;
    margin-bottom: 60px;
    align-items: flex-start;
}

.research-item:last-child {
    margin-bottom: 0;
}

.research-image {
    flex-shrink: 0;
}

.research-photo {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
}

.research-content {
    flex: 1;
}

.research-subtitle {
    font-size: 20px;
    font-weight: 600;
    color: #1e3a8a;
    margin-bottom: 20px;
}

.research-description {
    font-size: 16px;
    color: #555;
    line-height: 1.8;
    margin-bottom: 20px;
}

/* Members Section */
.members-section {
    padding: 80px 0;
    background-color: rgba(255, 255, 255, 0.95);
    background-image: url('../images/background-pattern-simple.svg');
    background-attachment: fixed;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

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

.member-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    border-bottom: 1px solid #e2e8f0;
}

.member-item:last-child {
    border-bottom: none;
}

.member-role {
    font-weight: 500;
    color: #555;
    flex: 1;
}

.member-name {
    font-weight: 600;
    color: #1e3a8a;
    flex: 1;
}

/* Contact Section */
.contact-section {
    padding: 80px 0;
    background-color: #f8fafc;
}

.contact-content {
    max-width: 600px;
    margin: 0 auto;
}

.contact-info h3 {
    font-size: 18px;
    font-weight: 600;
    color: #1e3a8a;
    margin-bottom: 10px;
}

.contact-info p {
    font-size: 16px;
    color: #555;
    margin-bottom: 20px;
}

/* Links Section */
.links-section {
    padding: 80px 0;
    background-color: rgba(255, 255, 255, 0.95);
    background-image: url('../images/background-pattern.svg');
    background-attachment: fixed;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.links-content {
    max-width: 600px;
    margin: 0 auto;
}

.link-item {
    display: block;
    padding: 15px 0;
    color: #1e3a8a;
    text-decoration: underline;
    font-weight: 500;
    transition: color 0.3s ease;
    border-bottom: 1px solid #e2e8f0;
}

.link-item:last-child {
    border-bottom: none;
}

.link-item:hover {
    color: #3b82f6;
}

/* Footer */
.footer {
    background-color: #1e3a8a;
    color: #fff;
    text-align: center;
    padding: 30px 0;
}

.footer p {
    font-size: 14px;
    opacity: 0.8;
}

/* Responsive Design */

/* Tablet (1024px and below) */
@media (max-width: 1024px) {
    .container {
        padding: 0 15px;
    }

    .nav-list {
        gap: 20px;
    }

    .logo-image {
        height: 55px;
        max-width: 280px;
    }

    .hero {
        height: 50vh;
        min-height: 350px;
        max-height: 500px;
    }

    .section-title {
        font-size: 28px;
    }

    .message-content,
    .research-item {
        gap: 30px;
    }

    .professor-photo,
    .research-photo {
        width: 180px;
        margin: auto;
    }
}

/* Small Tablet (768px and below) */
@media (max-width: 768px) {
    .nav {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .logo-image {
        height: 60px;
        max-width: 80%;
    }

    .hero {
        height: 45vh;
        min-height: 300px;
        max-height: 400px;
    }


    .section-title {
        font-size: 24px;
        margin-bottom: 40px;
    }

    .message-content,
    .research-item {
        flex-direction: column;
        gap: 20px;
    }

    .professor-photo,
    .research-photo {
        width: 150px;
        display: block;
        margin: 0 auto;
    }

    .professor-image,
    .message-text,
    .research-image {
        width: 100%;
    }

    .member-item {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }

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

/* Mobile (480px and below) */
@media (max-width: 480px) {
    .container {
        padding: 0 10px;
    }

    .header-content {
        padding: 10px 0;
    }

    .logo-image {
        height: 60px;
        max-width: 80%;
    }

    .hero {
        height: 40vh;
        min-height: 250px;
        max-height: 350px;
    }


    .section-title {
        font-size: 20px;
        margin-bottom: 30px;
    }

    .professor-photo,
    .research-photo {
        width: 120px;
        display: block;
        margin: auto;
    }

    .research-subtitle {
        font-size: 18px;
    }

    .research-description,
    .message-placeholder {
        font-size: 14px;
    }

    .member-item {
        padding: 15px 0;
    }

    .member-role,
    .member-name {
        font-size: 14px;
    }

    .contact-info h3 {
        font-size: 16px;
    }

    .contact-info p {
        font-size: 14px;
    }
}

/* Mobile Menu Styles */
.nav.active {
    display: block;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: #fff;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    padding: 20px;
    animation: slideDown 0.3s ease;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.nav.active .nav-list {
    flex-direction: column;
    gap: 15px;
}

.nav.active .nav-link {
    display: block;
    padding: 10px 0;
    border-bottom: 1px solid #e2e8f0;
    transition: color 0.3s ease;
}

.nav.active .nav-link:last-child {
    border-bottom: none;
}

.nav.active .nav-link:hover {
    color: #1e3a8a;
    padding-left: 10px;
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Focus styles for accessibility */
.nav-link:focus,
.related-link:focus,
.link-item:focus,
.mobile-menu-toggle:focus {
    outline: 2px solid #3b82f6;
    outline-offset: 2px;
}


/* Print styles */
@media print {

    .header,
    .mobile-menu-toggle,
    .scroll-to-top {
        display: none !important;
    }

    body {
        font-size: 12pt;
        line-height: 1.4;
    }

    .section-title {
        page-break-after: avoid;
    }

    .research-item,
    .member-item {
        page-break-inside: avoid;
    }
}

/* Animation for mobile menu toggle */
.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(-45deg) translate(-5px, 6px);
}

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

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(45deg) translate(-5px, -6px);
}

/* SVG Circle Animation */
@keyframes rotateCircle1 {
    from {
        transform: rotate(0deg) scale(1);
    }

    25% {
        transform: rotate(90deg) scale(1.1);
    }

    50% {
        transform: rotate(180deg) scale(1);
    }

    75% {
        transform: rotate(270deg) scale(0.9);
    }

    to {
        transform: rotate(360deg) scale(1);
    }
}

@keyframes rotateCircle2 {
    from {
        transform: rotate(0deg) scale(1);
    }

    25% {
        transform: rotate(-90deg) scale(0.9);
    }

    50% {
        transform: rotate(-180deg) scale(1.1);
    }

    75% {
        transform: rotate(-270deg) scale(1);
    }

    to {
        transform: rotate(-360deg) scale(1);
    }
}

@keyframes rotateCircle3 {
    from {
        transform: rotate(0deg) scale(1);
    }

    33% {
        transform: rotate(60deg) scale(1.05);
    }

    66% {
        transform: rotate(120deg) scale(0.95);
    }

    to {
        transform: rotate(180deg) scale(1);
    }
}

.rotating-circle-1 {
    animation: rotateCircle1 20s ease-in-out infinite;
    transform-origin: center;
}

.rotating-circle-2 {
    animation: rotateCircle2 25s ease-in-out infinite;
    transform-origin: center;
}

.rotating-circle-3 {
    animation: rotateCircle3 30s ease-in-out infinite;
    transform-origin: center;
}

a.related-link {
    display: inline-block;
    position: relative;
    margin: 0 auto;
    padding: .9em 2em;
    overflow: hidden;
    border: 1px solid #1d3177;
    border-radius: 5px;
    background-color: #fff;
    color: #1d3177;
    font-size: 1em;
    text-decoration: none;
    transition: all 0.3s ease;
}

a.related-link:hover {
    background-color: #1d3177;
    color: #fff;
    border-color: #1d3177;
}

a.related-link::before {
    position: absolute;
    top: 0;
    left: 0;
    z-index: -1;
    width: 100%;
    height: 100%;
    background-color: #1d3177;
    content: '';
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

a.related-link:hover::before {
    transform: scaleX(1);
}