/* 기본 스타일 리셋 및 설정 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --navy: #0a192f;
    --light-navy: #112240;
    --lightest-navy: #233554;
    --slate: #8892b0;
    --light-slate: #a8b2d1;
    --lightest-slate: #ccd6f6;
    --white: #e6f1ff;
    --green: #64ffda;
    --green-tint: rgba(100, 255, 218, 0.1);
    --font-sans: 'Calibre', 'Inter', 'San Francisco', 'SF Pro Text', -apple-system, system-ui, sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;
    --transition: all 0.25s cubic-bezier(0.645, 0.045, 0.355, 1);
}

body {
    font-family: var(--font-sans);
    line-height: 1.6;
    color: var(--slate);
    background-color: var(--navy);
    overflow-x: hidden;
}

/* 스크롤바 스타일 */
::-webkit-scrollbar {
    width: 12px;
}

::-webkit-scrollbar-track {
    background: var(--navy);
}

::-webkit-scrollbar-thumb {
    background: var(--lightest-navy);
    border-radius: 6px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--light-navy);
}

/* 사이드바 */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    width: 40px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    padding: 50px 0;
    z-index: 10;
    background-color: var(--navy);
    border-right: 1px solid var(--lightest-navy);
}

.logo {
    writing-mode: vertical-rl;
    text-orientation: mixed;
}

.logo a {
    font-family: var(--font-mono);
    font-size: 14px;
    color: var(--green);
    text-decoration: none;
    letter-spacing: 2px;
    transition: var(--transition);
}

.logo a:hover {
    color: var(--white);
    transform: translateY(-3px);
}

.nav-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.nav-link {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--light-slate);
    text-decoration: none;
    writing-mode: vertical-rl;
    text-orientation: mixed;
    padding: 10px;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover {
    color: var(--green);
    transform: translateY(-3px);
}

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

.nav-link.active::after {
    content: '';
    position: absolute;
    left: -2px;
    top: 50%;
    transform: translateY(-50%);
    width: 2px;
    height: 20px;
    background: var(--green);
}

.social-links {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

/* 메인 콘텐츠 */
.main {
    margin-left: 40px;
    min-height: 100vh;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 50px;
}

.section {
    min-height: 100vh;
    padding: 100px 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* Hero 섹션 */
.hero-section {
    padding: 150px 0 100px;
}

.hero-greeting {
    font-family: var(--font-mono);
    font-size: 16px;
    color: var(--green);
    margin-bottom: 20px;
}

.hero-name {
    font-size: 80px;
    font-weight: 700;
    color: var(--lightest-slate);
    margin-bottom: 10px;
    line-height: 1.1;
}

.hero-title {
    font-size: 60px;
    font-weight: 700;
    color: var(--slate);
    margin-bottom: 30px;
    line-height: 1.1;
}

.hero-description {
    font-size: 20px;
    color: var(--slate);
    max-width: 540px;
    margin-bottom: 50px;
    line-height: 1.5;
}

.hero-cta {
    margin-top: 50px;
}

/* 섹션 헤더 */
.section-number {
    font-family: var(--font-mono);
    font-size: 20px;
    color: var(--green);
    margin-bottom: 10px;
    display: inline-block;
}

.section-title {
    font-size: 40px;
    font-weight: 700;
    color: var(--lightest-slate);
    margin-bottom: 50px;
    display: flex;
    align-items: center;
    gap: 20px;
}

.section-title::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--lightest-navy);
    max-width: 300px;
}

/* About 섹션 */
.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 50px;
    align-items: start;
}

.about-text {
    font-size: 18px;
    line-height: 1.7;
    color: var(--slate);
}

.about-text p {
    margin-bottom: 20px;
}

.highlight {
    color: var(--green);
}

.skills-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(2, minmax(140px, 200px));
    gap: 10px;
    padding: 0;
    margin: 20px 0;
}

.skills-list li {
    position: relative;
    padding-left: 20px;
    font-family: var(--font-mono);
    font-size: 14px;
    color: var(--light-slate);
}

.skills-list li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--green);
}

.about-image {
    position: relative;
}

.image-wrapper {
    position: relative;
    max-width: 300px;
}

.image-placeholder {
    width: 100%;
    aspect-ratio: 1;
    background: var(--green-tint);
    border: 2px solid var(--green);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: var(--green);
    transition: var(--transition);
}

.image-placeholder:hover {
    transform: translateY(-5px);
}

.profile-img {
    width: 100%;
    height: auto;
    border-radius: 4px;
    border: 2px solid var(--green);
    display: block;
    transition: var(--transition);
    filter: grayscale(100%);
    opacity: 0.9;
}

.profile-img:hover {
    filter: grayscale(0%);
    opacity: 1;
    transform: translateY(-5px);
}

.image-wrapper::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 20px;
    width: 100%;
    height: 100%;
    border: 2px solid var(--green);
    border-radius: 4px;
    z-index: -1;
    transition: var(--transition);
}

.image-wrapper:hover::before {
    top: 15px;
    left: 15px;
}

/* Experience 섹션 */
.experience-container {
    display: flex;
    gap: 50px;
    margin-top: 30px;
}

.experience-tabs {
    display: flex;
    flex-direction: column;
    gap: 0;
    border-left: 2px solid var(--lightest-navy);
    min-width: 200px;
}

.tab-button {
    background: transparent;
    border: none;
    border-left: 2px solid transparent;
    padding: 12px 20px;
    text-align: left;
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--slate);
    cursor: pointer;
    transition: var(--transition);
    margin-left: -2px;
}

.tab-button:hover {
    background: var(--light-navy);
    color: var(--green);
}

.tab-button.active {
    border-left-color: var(--green);
    color: var(--green);
    background: var(--green-tint);
}

.experience-content {
    flex: 1;
}

.tab-content {
    display: none;
    animation: fadeIn 0.5s ease;
}

.tab-content.active {
    display: block;
}

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

.job-title {
    font-size: 22px;
    font-weight: 600;
    color: var(--lightest-slate);
    margin-bottom: 5px;
}

.company-name {
    color: var(--green);
}

.job-period {
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--light-slate);
    margin-bottom: 25px;
}

.job-description {
    list-style: none;
    padding: 0;
}

.job-description li {
    position: relative;
    padding-left: 30px;
    padding-bottom: 15px;
    color: var(--slate);
    line-height: 1.6;
    font-size: 16px;
}

.job-description li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--green);
    font-size: 18px;
}

.project-period {
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--green);
    margin-right: 10px;
}

/* Projects 섹션 */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.project-placeholder {
    padding: 100px 20px;
    text-align: center;
    color: var(--slate);
    border: 2px dashed var(--lightest-navy);
    border-radius: 4px;
    font-size: 16px;
}

/* Contact 섹션 */
.contact-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-text {
    font-size: 18px;
    color: var(--slate);
    margin-bottom: 50px;
    line-height: 1.7;
}

.btn {
    display: inline-block;
    padding: 18px 28px;
    font-family: var(--font-mono);
    font-size: 14px;
    color: var(--green);
    text-decoration: none;
    border: 1px solid var(--green);
    border-radius: 4px;
    background: transparent;
    transition: var(--transition);
    cursor: pointer;
}

.btn:hover {
    background: var(--green-tint);
    transform: translateY(-3px);
}

.contact-info {
    margin-top: 60px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.contact-item {
    font-size: 16px;
    color: var(--slate);
}

.contact-label {
    color: var(--green);
    margin-right: 10px;
}

.contact-item a {
    color: var(--light-slate);
    text-decoration: none;
    transition: var(--transition);
}

.contact-item a:hover {
    color: var(--green);
}

/* Footer */
.footer {
    text-align: center;
    padding: 30px 0;
    border-top: 1px solid var(--lightest-navy);
    margin-top: 100px;
}

.footer p {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--slate);
    margin-bottom: 5px;
}

.footer-year {
    color: var(--light-slate);
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .sidebar {
        display: none;
    }

    .main {
        margin-left: 0;
    }

    .container {
        padding: 0 25px;
    }

    .hero-name {
        font-size: 50px;
    }

    .hero-title {
        font-size: 40px;
    }

    .hero-description {
        font-size: 18px;
    }

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

    .section-title::after {
        display: none;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .experience-container {
        flex-direction: column;
    }

    .experience-tabs {
        flex-direction: row;
        overflow-x: auto;
        border-left: none;
        border-bottom: 2px solid var(--lightest-navy);
        min-width: auto;
    }

    .tab-button {
        border-left: none;
        border-bottom: 2px solid transparent;
        margin-left: 0;
        margin-bottom: -2px;
        white-space: nowrap;
    }

    .tab-button.active {
        border-left: none;
        border-bottom-color: var(--green);
    }

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

/* 스크롤 애니메이션 */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}