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

body {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    line-height: 1.7;
    color: #333;
    background-color: #f1f1f1;
}

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

/* Header & Navigation */
header {
    background-color: #ffffff;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
}

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

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    color: #333;
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: #666;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.nav-links a:hover {
    background-color: #f8f9fa;
    color: #333;
}

/* Hamburger Menu */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: #666;
    margin: 3px 0;
    transition: 0.3s;
}

/* Main Content */
main {
    margin-top: 80px;
}

.section {
    padding: 4rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 3rem;
    text-align: center;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background-color: #888;
    margin: 1rem auto 0;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #333 0%, #666 100%);
    color: white;
    text-align: center;
    padding: 6rem 0;
    min-height: 70vh;
    display: flex;
    align-items: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
}

.hero-tagline {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: #e9ecef;
    font-weight: 400;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2.5rem;
    color: #ddd;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-button {
    display: inline-block;
    background-color: #888;
    color: white;
    padding: 0.8rem 2rem;
    text-decoration: none;
    border-radius: 5px;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid #888;
}

.cta-button:hover {
    background-color: transparent;
    color: #888;
    background-color: white;
}

/* Profile Photo Section */
.profile-section {
    background-color: white;
    text-align: center;
    padding: 4rem 0;
}

.profile-photo {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    margin: 0 auto 2rem;
    background-image: url('../profile.jpg');
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    justify-content: center;
    color: transparent;
    font-size: 3rem;
    font-weight: 700;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.profile-intro {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.1rem;
    color: #555;
    line-height: 1.8;
}

/* Achievements Section */
.achievements {
    background-color: white;
}

.achievement-item {
    background-color: #f8f9fa;
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    border-left: 4px solid #888;
    overflow: hidden;
}

.achievement-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem 2.5rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
    position: relative;
}

.achievement-header:hover {
    background-color: #e9ecef;
}

.achievement-header-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    width: 100%;
}

.achievement-company {
    font-size: 1.5rem;
    font-weight: 700;
    color: #333;
}

.achievement-period {
    color: #888;
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    white-space: nowrap;
}

.achievement-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #555;
    margin-top: 0.5rem;
}

.achievement-icon {
    color: #888;
    font-size: 1.2rem;
    margin-left: 1rem;
    transition: transform 0.3s ease;
}

.achievement-icon.expanded {
    transform: rotate(180deg);
}

.achievement-details {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    color: #555;
    line-height: 1.7;
    background-color: white;
}

.achievement-details.expanded {
    max-height: 1000px;
    padding: 2rem 2.5rem;
}

.achievement-details p {
    margin-bottom: 1rem;
}

.achievement-details ul {
    list-style: none;
    padding: 0;
    margin-top: 1rem;
}

.achievement-details li {
    margin-bottom: 0.7rem;
    padding-left: 1.5rem;
    position: relative;
}

.achievement-details li::before {
    content: '●';
    position: absolute;
    left: 0;
    color: #888;
    font-weight: 700;
}

@media (max-width: 768px) {
    .achievement-header-content {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .achievement-period {
        margin-top: 0.5rem;
    }
    
    .achievement-header {
        padding: 1.5rem;
    }
    
    .achievement-details.expanded {
        padding: 1.5rem;
    }
}

/* Experience Section - Timeline Style */
.experience {
    background-color: #f8f9fa;
}

.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(to bottom, #888, #ddd);
    transform: translateX(-50%);
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    width: 100%;
}

.timeline-item:nth-child(odd) .timeline-content {
    margin-left: 0;
    margin-right: calc(50% + 2rem);
    text-align: right;
}

.timeline-item:nth-child(even) .timeline-content {
    margin-left: calc(50% + 2rem);
    margin-right: 0;
    text-align: left;
}

.timeline-content {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: relative;
}

.timeline-item:nth-child(odd) .timeline-content::before {
    content: '';
    position: absolute;
    right: -10px;
    top: 50%;
    transform: translateY(-50%);
    border: 10px solid transparent;
    border-left-color: white;
}

.timeline-item:nth-child(even) .timeline-content::before {
    content: '';
    position: absolute;
    left: -10px;
    top: 50%;
    transform: translateY(-50%);
    border: 10px solid transparent;
    border-right-color: white;
}

.timeline-date {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    background: #888;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
    white-space: nowrap;
    z-index: 10;
}

.timeline-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1rem;
}

.timeline-description {
    color: #555;
    line-height: 1.7;
}

@media (max-width: 768px) {
    .timeline {
        padding-left: 1rem;
    }
    
    .timeline::before {
        left: 1.5rem;
    }
    
    .timeline-item {
        margin-bottom: 4rem;
    }
    
    .timeline-item:nth-child(odd) .timeline-content,
    .timeline-item:nth-child(even) .timeline-content {
        margin-left: 4rem;
        margin-right: 1rem;
        text-align: left;
        margin-top: 2.5rem;
    }
    
    .timeline-item:nth-child(odd) .timeline-content::before,
    .timeline-item:nth-child(even) .timeline-content::before {
        left: -10px;
        right: auto;
        border: 10px solid transparent;
        border-right-color: white;
        border-left-color: transparent;
    }
    
    .timeline-date {
        left: 1.5rem;
        top: 0;
        transform: translateX(-50%);
        position: absolute;
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
        margin-bottom: 1rem;
    }
}

/* Skills Section - Simple List Style */
.skills {
    background-color: white;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.skills-category {
    margin-bottom: 2rem;
}

.skills-category h3 {
    font-size: 1.3rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #888;
}

.skills-list {
    list-style: none;
    padding: 0;
}

.skills-list li {
    margin-bottom: 1rem;
    padding: 0.8rem 0;
    border-bottom: 1px solid #eee;
    color: #555;
    line-height: 1.6;
}

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

.skill-name {
    font-weight: 600;
    color: #333;
    display: inline-block;
    margin-right: 0.5rem;
}

.skill-description {
    color: #666;
}

/* Services Section */
.services {
    background-color: #f8f9fa;
}

.service-item {
    background-color: white;
    padding: 2.5rem;
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    border-top: 4px solid #888;
}

.service-item h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1.5rem;
}

.service-item ul {
    list-style: none;
    padding: 0;
}

.service-item li {
    margin-bottom: 0.8rem;
    padding-left: 1.5rem;
    position: relative;
    color: #555;
}

.service-item li::before {
    content: '●';
    position: absolute;
    left: 0;
    color: #888;
    font-weight: 700;
}

/* Footer */
footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 3rem 0;
}

.social-links {
    margin-top: 1.5rem;
    display: flex;
    justify-content: center;
    gap: 2rem;
}

.social-links a {
    color: #ddd;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border: 1px solid #ddd;
    border-radius: 5px;
    transition: all 0.3s ease;
    display: inline-block;
    text-align: center;
}

.social-links a:hover {
    background-color: #ddd;
    color: #333;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .hero-content h1 {
        font-size: 2.5rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .profile-photo {
        width: 150px;
        height: 150px;
        font-size: 2.5rem;
    }
    
    .social-links {
        flex-direction: row;
        gap: 1rem;
        align-items: center;
        justify-content: center;
    }
}

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