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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    background: #0f0f0f;
    color: #e0e0e0;
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    position: relative;
    overflow-x: hidden;
}

.particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.particle {
    position: absolute;
    background: rgba(59, 130, 246, 0.3);
    border-radius: 50%;
    pointer-events: none;
}

.container {
    max-width: 880px;
    margin: 0 auto;
    padding: 80px 24px;
    position: relative;
    z-index: 1;
}

header {
    margin-bottom: 72px;
}

.profile-section {
    display: flex;
    align-items: center;
    gap: 48px;
}

.profile-image img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    filter: grayscale(20%);
}

.profile-info h1 {
    font-size: 2.75em;
    margin-bottom: 8px;
    color: #ffffff;
    font-weight: 600;
    letter-spacing: -0.03em;
}

.profile-info h2 {
    font-size: 1.25em;
    color: #888;
    font-weight: 400;
    margin-bottom: 16px;
}

.certification {
    display: inline-flex;
    align-items: center;
    background: rgba(255, 255, 255, 0.06);
    color: #3b82f6;
    padding: 6px 14px;
    border-radius: 6px;
    font-size: 0.875em;
    font-weight: 500;
    border: 1px solid rgba(59, 130, 246, 0.2);
}

section {
    margin-bottom: 64px;
}

.section-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    background: none;
    border: none;
    padding: 0;
    cursor: pointer;
    margin-bottom: 0;
    transition: opacity 0.2s ease;
    font-size: inherit;
    font-family: inherit;
    text-align: left;
}

.section-toggle.expanded {
    margin-bottom: 24px;
}

.section-toggle:hover {
    opacity: 0.7;
}

.section-toggle h3 {
    margin: 0;
    font-size: 1.625em !important;
    color: #ffffff;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.toggle-icon {
    color: #666;
    transition: transform 0.3s ease;
    flex-shrink: 0;
    margin-left: 12px;
}

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

.section-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
}

h3 {
    font-size: 1.625em;
    color: #ffffff;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.experience-note {
    color: #666;
    font-size: 0.9375em;
    margin-bottom: 24px;
    margin-top: 0;
}

.about p {
    margin-bottom: 16px;
    font-size: 1.0625em;
    color: #b0b0b0;
    line-height: 1.7;
}

.about strong {
    color: #e0e0e0;
    font-weight: 500;
}

.skills-category {
    margin-bottom: 32px;
}

.skills-category:last-child {
    margin-bottom: 0;
}

.skills-category h4 {
    font-size: 0.875em;
    color: #666;
    margin-bottom: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.skills {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.skills span {
    background: rgba(255, 255, 255, 0.04);
    color: #b0b0b0;
    padding: 8px 14px;
    border-radius: 6px;
    font-size: 0.9375em;
    font-weight: 400;
    border: 1px solid rgba(255, 255, 255, 0.08);
    transition: all 0.2s ease;
}

.skills span:hover {
    background: rgba(255, 255, 255, 0.08);
    color: #e0e0e0;
    border-color: rgba(255, 255, 255, 0.15);
}

.job {
    margin-bottom: 32px;
    padding-bottom: 32px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.job:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.job-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 6px;
    flex-wrap: wrap;
    gap: 12px;
}

.job h4 {
    font-size: 1.0625em;
    color: #ffffff;
    font-weight: 500;
}

.period {
    color: #666;
    font-size: 0.875em;
    font-weight: 400;
}

.company {
    color: #888;
    font-weight: 400;
    margin-bottom: 8px;
    font-size: 0.9375em;
}

.description {
    color: #888;
    font-size: 0.9375em;
    margin-top: 8px;
    line-height: 1.6;
}

footer {
    text-align: center;
    padding: 48px 0 32px;
    color: #444;
    font-size: 0.875em;
}

@media (max-width: 768px) {
    .container {
        padding: 48px 20px;
    }

    .profile-section {
        flex-direction: column;
        align-items: flex-start;
        gap: 24px;
    }

    .profile-image img {
        width: 96px;
        height: 96px;
    }

    .profile-info h1 {
        font-size: 2em;
    }

    .profile-info h2 {
        font-size: 1em;
    }

    .job-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
    }

    h3 {
        font-size: 1.25em;
    }

    section {
        margin-bottom: 48px;
    }
}