:root {
    --primary-color: #FF2100;
    --primary-hover: #E61E00;
    --text-color: #000000;
    --text-secondary: #444444;
    --text-muted: #888888;
    --bg-color: #FFFFFF;
    --bg-secondary: #F5F5F5;
    --bg-dark: #111111;
    --border-color: #EEEEEE;
    --container-width: 900px;
    --header-height: 70px;
    --transition: all 0.5s cubic-bezier(0.2, 0.8, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.5;
    word-break: keep-all;
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

#progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 2px;
    background-color: var(--primary-color);
    width: 0;
    z-index: 2000;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 30px;
}

/* Header */
.header {
    height: var(--header-height);
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
}

.header__inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    font-size: 18px;
    font-weight: 900;
    letter-spacing: -1px;
    color: var(--text-color);
}

.logo span {
    color: var(--text-muted);
    font-weight: 500;
    margin-left: 4px;
}

.nav__list {
    display: flex;
    gap: 30px;
    list-style: none;
}

.nav__link {
    font-size: 14px;
    font-weight: 800;
    color: var(--text-color);
}

.nav__link:hover {
    color: var(--primary-color);
}

.btn {
    padding: 8px 16px;
    border-radius: 2px;
    font-weight: 700;
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition);
    border: none;
}

.btn--primary {
    background-color: var(--primary-color);
    color: white;
}

.btn--outline {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.btn--outline:hover {
    background-color: var(--bg-secondary);
    color: var(--text-color);
}

/* Sections */
.section {
    padding: 120px 0;
}

.section--bg {
    background-color: var(--bg-secondary);
}

.section__title {
    font-size: 36px;
    font-weight: 900;
    margin-bottom: 60px;
    letter-spacing: -1.5px;
    line-height: 1.1;
}

/* Hero */
.hero {
    padding: 180px 0 100px;
}

.hero__label {
    font-size: 13px;
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: 24px;
    display: block;
}

.hero__title {
    font-size: 64px;
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 50px;
    letter-spacing: -3px;
}

.hero__title span {
    color: var(--primary-color);
}

.hero__info {
    font-size: 18px;
    color: var(--text-secondary);
    font-weight: 500;
}

.hero__tags {
    margin-top: 30px;
    display: flex;
    gap: 12px;
}

.tag {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-muted);
}

/* Philosophy */
.philosophy {
    background-color: var(--text-color);
    color: white;
    padding: 120px 0;
    text-align: center;
}

.philosophy__text {
    font-size: 28px;
    font-weight: 800;
    line-height: 1.4;
    max-width: 750px;
    margin: 0 auto;
}

.philosophy__text span {
    color: var(--primary-color);
}

/* About */
.about__content {
    max-width: 800px;
}

.about__text {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 30px;
    line-height: 1.7;
}

.about__text strong {
    color: var(--text-color);
    font-weight: 800;
}

/* Key Competencies */
.competencies {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 60px;
    padding-top: 60px;
    border-top: 1px solid var(--border-color);
}

.comp-item h3 {
    font-size: 16px;
    font-weight: 900;
    margin-bottom: 12px;
    color: var(--text-color);
}

.comp-item p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Experience */
.timeline {
    display: flex;
    flex-direction: column;
    gap: 80px;
}

.timeline__item {
    display: grid;
    grid-template-columns: 240px 1fr;
    gap: 40px;
}

.timeline__company {
    font-size: 24px;
    font-weight: 900;
    letter-spacing: -0.5px;
}

.badge {
    font-size: 10px;
    padding: 3px 8px;
    background-color: var(--primary-color);
    color: white;
    font-weight: 800;
    border-radius: 2px;
    margin-left: 5px;
}

.timeline__role {
    font-weight: 800;
    font-size: 16px;
    color: var(--text-color);
    margin-bottom: 10px;
}

.timeline__date {
    font-size: 14px;
    color: var(--text-muted);
    font-weight: 500;
}

.list {
    list-style: none;
    margin-top: 15px;
}

.list li {
    position: relative;
    padding-left: 15px;
    font-size: 15px;
    margin-bottom: 10px;
    color: var(--text-secondary);
}

.list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 10px;
    width: 4px;
    height: 4px;
    background-color: var(--primary-color);
}

.text-highlight {
    color: var(--primary-color);
    font-weight: 800;
}

/* Tags */
.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 20px;
}

.tags span {
    font-size: 11px;
    font-weight: 800;
    padding: 4px 10px;
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    border-radius: 2px;
    border: 1px solid #eee;
    text-transform: uppercase;
}

/* Projects */
.projects__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.project-summary-card {
    background-color: var(--bg-color);
    padding: 40px;
    cursor: pointer;
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.project-summary-card:hover {
    border-color: var(--text-color);
    box-shadow: 0 15px 40px rgba(0,0,0,0.05);
}

.project-summary-card__label {
    font-size: 11px;
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.project-summary-card__title {
    font-size: 20px;
    font-weight: 900;
    margin-bottom: 15px;
}

.project-summary-card__desc {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 25px;
}

.project-summary-card__more {
    font-size: 13px;
    font-weight: 800;
    color: var(--primary-color);
}

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    backdrop-filter: blur(10px);
    z-index: 3000;
    display: none;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.modal {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -40%);
    width: 90%;
    max-width: 800px;
    max-height: 85vh;
    background-color: var(--bg-color);
    z-index: 3001;
    display: none;
    padding: 60px;
    overflow-y: auto;
    opacity: 0;
    transition: all 0.5s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.modal.active {
    opacity: 1;
    transform: translate(-50%, -50%);
}

.modal__close {
    position: absolute;
    top: 24px;
    right: 24px;
    font-size: 36px;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-muted);
    line-height: 1;
}

.modal__title {
    font-size: 28px;
    font-weight: 900;
    margin-bottom: 30px;
}

.modal__section--summary {
    background-color: var(--bg-secondary);
    padding: 30px;
    border-left: 6px solid var(--primary-color);
    margin-bottom: 40px;
}

.summary-list {
    list-style: none;
}

.summary-list li {
    font-size: 14px !important;
    margin-bottom: 10px !important;
    color: var(--text-secondary);
}

.summary-list li strong {
    color: var(--text-color);
    display: inline-block;
    width: 100px;
}

.modal__section h3 {
    font-size: 14px;
    font-weight: 900;
    margin-bottom: 15px;
    text-transform: uppercase;
}

.modal__section p {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

/* Footer */
.footer {
    padding: 100px 0;
    background-color: var(--bg-dark);
    color: white;
    text-align: center;
}

.footer__title {
    font-size: 32px;
    font-weight: 900;
    margin-bottom: 20px;
}

.footer__contact a {
    font-size: 20px;
    font-weight: 800;
}

.footer__contact a:hover {
    color: var(--primary-color);
}

/* Animations */
.reveal {
    opacity: 1 !important;
    transform: translateY(0) !important;
}

/* Back to Top Button */
#back-to-top {
    position: fixed;
    bottom: 40px;
    right: 40px;
    width: 50px;
    height: 50px;
    background-color: var(--text-color);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 20px;
    font-weight: 900;
    cursor: pointer;
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

#back-to-top.show {
    opacity: 1;
    visibility: visible;
}

#back-to-top:hover {
    background-color: var(--primary-color);
    transform: translateY(-5px);
}

/* Responsive Optimization */
@media (max-width: 1024px) {
    .hero__title { font-size: 52px; }
    .container { padding: 0 40px; }
}

@media (max-width: 768px) {
    :root {
        --header-height: 60px;
    }
    
    .container { padding: 0 24px; }
    
    .header__actions #copy-link { display: none; } /* 모바일에서 링크 복사 숨김 */
    .nav__list { gap: 15px; }
    .nav__link { font-size: 13px; }
    
    .section { padding: 80px 0; }
    .section__title { font-size: 28px; margin-bottom: 40px; }
    
    .hero { padding: 140px 0 60px; }
    .hero__title { font-size: 36px; letter-spacing: -1.5px; margin-bottom: 30px; }
    .hero__info { font-size: 15px; }
    
    .philosophy { padding: 80px 0; }
    .philosophy__text { font-size: 20px; }
    
    .competencies { grid-template-columns: 1fr; gap: 30px; padding-top: 40px; margin-top: 40px; }
    
    .timeline { gap: 50px; }
    .timeline__item { grid-template-columns: 1fr; gap: 10px; }
    .timeline__company { font-size: 18px; }
    
    .projects__grid { grid-template-columns: 1fr; gap: 20px; }
    .project-summary-card { padding: 30px 24px; }
    .project-summary-card__title { font-size: 18px; }
    
    .modal { 
        width: 100%; 
        height: 100%; 
        max-height: 100vh; 
        top: 0; 
        left: 0; 
        transform: none; 
        padding: 60px 24px; 
    }
    .modal.active { transform: none; }
    .modal__close { top: 20px; right: 20px; font-size: 30px; }
    .modal__title { font-size: 22px; }
    .modal__section--summary { padding: 20px; }
    
    #back-to-top { bottom: 20px; right: 20px; width: 45px; height: 45px; }
    
    .footer__title { font-size: 24px; }
}

@media (max-width: 480px) {
    .hero__title { font-size: 32px; }
    .nav__list { display: none; } /* 아주 작은 화면에선 메뉴 숨김 */
    .logo { font-size: 16px; }
}