:root {
    --keio-blue: rgb(0, 30, 98);
    --keio-red: rgb(198, 53, 39);
    --keio-yellow: rgb(241, 196, 0);
    --white: #ffffff;
    --light-gray: #f8f9fa;
    --text-dark: #1a1a1a;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans JP', sans-serif;
    background: var(--white);
    color: var(--text-dark);
    overflow-x: hidden;
    line-height: 1.8;
}

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 1px 0 rgba(0, 30, 98, 0.1);
    transition: all 0.3s ease;
}

header.scrolled {
    box-shadow: 0 4px 20px rgba(0, 30, 98, 0.1);
}

.header-inner {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0.75rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 1rem;
    text-decoration: none;
    color: var(--keio-blue);
}

.logo svg {
    width: 50px;
    height: auto;
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.logo-text .main {
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    color: var(--keio-blue);
}

.logo-text .sub {
    font-size: 0.65rem;
    letter-spacing: 0.15em;
    color: var(--keio-blue);
    opacity: 0.7;
}

nav {
    display: flex;
    align-items: center;
    gap: 2rem;
}

nav a {
    text-decoration: none;
    color: var(--keio-blue);
    font-size: 0.9rem;
    font-weight: 500;
    position: relative;
    padding: 0.5rem 0;
    transition: color 0.3s ease;
}

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--keio-red);
    transition: width 0.3s ease;
}

nav a:hover::after {
    width: 100%;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 6px;
    cursor: pointer;
    padding: 10px;
}

.mobile-menu-btn span {
    width: 25px;
    height: 2px;
    background: var(--keio-blue);
    transition: all 0.3s ease;
}

/* Page Header */
.page-header {
    padding: 8rem 2rem 4rem;
    background: linear-gradient(135deg, var(--white) 0%, var(--light-gray) 100%);
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    opacity: 0.03;
    background-image: repeating-linear-gradient(
        45deg,
        var(--keio-blue) 0,
        var(--keio-blue) 1px,
        transparent 0,
        transparent 50%
    );
    background-size: 60px 60px;
}

.page-header-content {
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.page-header h1 {
    font-family: 'Cormorant Garamond', serif;
    font-size: 3rem;
    font-weight: 400;
    color: var(--keio-blue);
    margin-bottom: 0.5rem;
}

.page-header .subtitle {
    font-size: 1rem;
    color: var(--keio-blue);
    opacity: 0.7;
}

.page-header .accent-line {
    width: 60px;
    height: 3px;
    background: var(--keio-red);
    margin-top: 1.5rem;
}

/* Main Content */
.main-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.main-content h2 {
    font-size: 1.5rem;
    color: var(--keio-blue);
    margin: 3rem 0 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--keio-blue);
}

.main-content h3 {
    font-size: 1.2rem;
    color: var(--keio-blue);
    margin: 2rem 0 1rem;
}

.main-content h4 {
    font-size: 1.1rem;
    color: var(--keio-blue);
    margin: 1.5rem 0 0.75rem;
}

.main-content p {
    margin-bottom: 1.5rem;
    line-height: 2;
}

.main-content ul, .main-content ol {
    margin: 1rem 0 1.5rem 1.5rem;
}

.main-content li {
    margin-bottom: 0.5rem;
}

.main-content a {
    color: var(--keio-blue);
    text-decoration: underline;
    transition: color 0.3s ease;
}

.main-content a:hover {
    color: var(--keio-red);
}

/* Button */
.btn {
    display: inline-block;
    padding: 1rem 2rem;
    background: var(--keio-blue);
    color: white;
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn:hover {
    background: var(--keio-red);
    color: white;
}

.btn-secondary {
    background: transparent;
    border: 2px solid var(--keio-blue);
    color: var(--keio-blue);
}

.btn-secondary:hover {
    background: var(--keio-blue);
    color: white;
}

/* Cards */
.info-card {
    background: var(--light-gray);
    padding: 2rem;
    border-radius: 8px;
    margin: 2rem 0;
    border-left: 4px solid var(--keio-blue);
}

.warning-card {
    background: #fff8e6;
    padding: 2rem;
    border-radius: 8px;
    margin: 2rem 0;
    border-left: 4px solid var(--keio-yellow);
}

/* Footer */
footer {
    background: var(--white);
    border-top: 1px solid rgba(0, 30, 98, 0.1);
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem 2rem;
}

.footer-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 1rem;
    text-decoration: none;
}

.footer-logo svg {
    width: 60px;
    height: auto;
}

.footer-logo-text {
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--keio-blue);
    letter-spacing: 0.1em;
}

.footer-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-nav a {
    text-decoration: none;
    color: var(--keio-blue);
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.footer-nav a:hover {
    color: var(--keio-red);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(0, 30, 98, 0.1);
}

.footer-bottom p {
    font-size: 0.8rem;
    color: #999;
}

/* Footer SNS Links */
.footer-sns {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-sns-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--keio-blue);
    font-size: 0.9rem;
    transition: all 0.3s ease;
    padding: 0.5rem 1rem;
    border-radius: 4px;
}

.footer-sns-link:hover {
    background: var(--light-gray);
    color: var(--keio-red);
}

.footer-sns-link svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

/* Animations */
.fade-in {
    opacity: 0;
    animation: fadeIn 0.8s ease forwards;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.8s ease;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .header-inner {
        padding: 0.75rem 1rem;
    }

    nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 2rem;
        gap: 1.5rem;
        box-shadow: 0 10px 30px rgba(0, 30, 98, 0.1);
    }

    nav.active {
        display: flex;
    }

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

    .logo-text .main {
        font-size: 1.2rem;
    }

    .page-header {
        padding: 6rem 1.5rem 3rem;
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .main-content {
        padding: 3rem 1.5rem;
    }

    .footer-top {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .footer-nav {
        justify-content: center;
    }
}