:root {
    --text: #222222;
    --text-secondary: #5f6368;
    --text-light: #777777;
    --accent: #2f5d8a;
    --accent-dark: #1f3f5f;
    --border: #e3e6e8;
    --background: #ffffff;
    --background-soft: #f7f8f9;
    --max-width: 1180px;
}

html {
    scroll-behavior: smooth;
}

* {
    box-sizing: border-box;
}

body {
    font-family: "Cabin", sans-serif;
    margin: 0;
    padding: 0;
    background: var(--background);
    color: var(--text);
    line-height: 1.6;
}

a {
    color: var(--accent);
    text-decoration-thickness: 1px;
    text-underline-offset: 3px;
}

a:hover {
    color: var(--accent-dark);
}

.skip-link {
    position: absolute;
    top: -100px;
    left: 20px;
    background: var(--text);
    color: white;
    padding: 10px 15px;
    z-index: 2000;
    text-decoration: none;
}

.skip-link:focus {
    top: 10px;
}

.navbar {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.97);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(8px);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 17px 30px;
    display: flex;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
}

.nav-container a {
    color: var(--text);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: color 0.2s ease;
}

.nav-container a:hover {
    color: var(--accent);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 65px 30px 80px;
}

section {
    margin-bottom: 85px;
    scroll-margin-top: 100px;
}

section h2 {
    font-size: 30px;
    line-height: 1.2;
    margin: 0 0 28px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border);
}

section h3 {
    font-size: 20px;
    line-height: 1.35;
}

section p {
    font-size: 17px;
    line-height: 1.7;
    text-align: left;
}

.intro {
    display: grid;
    grid-template-columns: 230px minmax(0, 1fr);
    gap: 55px;
    align-items: start;
    margin-bottom: 95px;
}

.profile-column {
    display: flex;
    justify-content: center;
}

.profile-photo {
    width: 215px;
    height: 215px;
    object-fit: cover;
    border-radius: 50%;
    border: 1px solid var(--border);
}

.intro-content {
    min-width: 0;
}

.intro-content h1 {
    font-size: 46px;
    line-height: 1.1;
    margin: 0 0 12px;
}

.position {
    margin: 0 0 13px;
    font-size: 20px;
    line-height: 1.45;
    color: #444444;
    font-weight: 500;
}

.research-line {
    margin: 0;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-secondary);
}

.research-line span {
    padding: 0 5px;
    color: #aaaaaa;
}

.bio {
    max-width: 860px;
    margin: 22px 0 0;
}

.quick-links {
    display: flex;
    gap: 18px;
    flex-wrap: wrap;
    margin-top: 24px;
}

.quick-links a {
    display: inline-block;
    font-weight: 600;
    text-decoration: none;
    padding-bottom: 2px;
    border-bottom: 1px solid transparent;
}

.quick-links a:hover {
    border-bottom-color: currentColor;
}

.education-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 35px;
}

.education-item {
    padding: 24px 26px;
    border: 1px solid var(--border);
    border-radius: 10px;
    background: var(--background);
}

.education-item h3 {
    margin: 4px 0 8px;
}

.education-item p {
    margin: 5px 0;
}

.education-specialization {
    color: var(--text-secondary);
}

.section-label {
    margin: 0;
    font-size: 14px;
    color: var(--accent);
    font-weight: 600;
    letter-spacing: 0.02em;
}

.research-grid {
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 55px;
}

.research-block h3 {
    margin-top: 0;
}

.research-block p {
    margin-top: 0;
    margin-bottom: 20px;
}

.thesis-block {
    padding-left: 28px;
    border-left: 3px solid var(--border);
}

.thesis-title {
    font-size: 18px;
    font-weight: 700;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 26px;
}

.project-item {
    display: flex;
    flex-direction: column;
    min-height: 100%;
    padding: 24px;
    border: 1px solid var(--border);
    border-radius: 10px;
    background: var(--background);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.project-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 24px rgba(0, 0, 0, 0.08);
}

.project-context {
    margin: 0 0 10px;
    font-size: 14px;
    color: var(--accent);
    font-weight: 600;
}

.project-item h3 {
    margin: 0 0 14px;
}

.project-item > p:not(.project-context) {
    margin: 0 0 18px;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: auto;
}

.project-tags span {
    display: inline-block;
    padding: 5px 9px;
    border-radius: 20px;
    background: var(--background-soft);
    color: var(--text-secondary);
    font-size: 13px;
}

.teaching-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 55px;
}

.teaching-grid h3:first-child {
    margin-top: 0;
}

.course-list {
    display: grid;
    gap: 10px;
    margin-top: 15px;
}

.course-item {
    display: grid;
    grid-template-columns: 75px 1fr;
    gap: 14px;
    padding: 11px 14px;
    background: var(--background-soft);
    border-radius: 7px;
}

.course-item strong {
    color: var(--accent);
}

.responsibility-list {
    padding-left: 21px;
    margin-top: 10px;
    line-height: 1.75;
}

.responsibility-list li {
    margin-bottom: 10px;
    padding-left: 4px;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 25px;
}

.skill-group {
    padding: 20px 22px;
    border-left: 3px solid var(--border);
}

.skill-group h3 {
    margin: 0 0 8px;
}

.skill-group p {
    margin: 0;
    color: var(--text-secondary);
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 22px;
}

.achievement-item {
    padding: 18px 20px;
    border-left: 3px solid #d9d9d9;
    background: var(--background-soft);
}

.achievement-item h3 {
    margin: 2px 0 5px;
}

.achievement-item p {
    margin: 0;
}

.achievement-year {
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
}

.personal-content {
    max-width: 850px;
}

.personal-content p {
    margin-top: 0;
    margin-bottom: 18px;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 35px;
}

.contact-grid > div {
    padding: 20px 22px;
    background: var(--background-soft);
    border-radius: 8px;
}

.contact-label {
    margin: 0 0 4px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
}

.contact-grid a {
    font-size: 17px;
}

footer {
    border-top: 1px solid var(--border);
    padding: 25px 30px;
    color: var(--text-light);
}

.footer-content {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    gap: 20px;
    font-size: 14px;
}

.footer-content p {
    margin: 0;
}

@media (max-width: 1000px) {
    .projects-grid {
        grid-template-columns: 1fr 1fr;
    }

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

@media (max-width: 800px) {
    .container {
        padding-top: 45px;
    }

    .intro {
        grid-template-columns: 180px 1fr;
        gap: 35px;
    }

    .profile-photo {
        width: 170px;
        height: 170px;
    }

    .intro-content h1 {
        font-size: 39px;
    }

    .education-grid,
    .research-grid,
    .teaching-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }

    .thesis-block {
        padding-left: 0;
        padding-top: 20px;
        border-left: none;
        border-top: 2px solid var(--border);
    }
}

@media (max-width: 650px) {
    .nav-container {
        gap: 12px 18px;
        padding: 14px 20px;
    }

    .nav-container a {
        font-size: 14px;
    }

    .container {
        padding: 40px 20px 65px;
    }

    section {
        margin-bottom: 65px;
        scroll-margin-top: 130px;
    }

    section h2 {
        font-size: 27px;
    }

    .intro {
        grid-template-columns: 1fr;
        gap: 24px;
        text-align: center;
    }

    .profile-photo {
        width: 180px;
        height: 180px;
    }

    .intro-content h1 {
        font-size: 38px;
    }

    .position,
    .research-line {
        text-align: center;
    }

    .bio {
        text-align: left;
    }

    .quick-links {
        justify-content: center;
    }

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

    .education-item,
    .project-item {
        padding: 20px;
    }

    .course-item {
        grid-template-columns: 65px 1fr;
    }

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

@media (max-width: 420px) {
    .nav-container {
        justify-content: center;
    }

    .intro-content h1 {
        font-size: 34px;
    }

    .position {
        font-size: 18px;
    }

    section h2 {
        font-size: 25px;
    }
}