:root {
    --bg-color-dark: #1a202c;
    --bg-color-darker: #2d3748;
    --text-color-dark: #E2E8F0;
    --highlight-color-dark: #4FD1C5;
    --card-color-dark: #4A5568;
}
body {
    font-family: 'Inter', sans-serif;
    transition: background-color 0.5s ease;
    background-color: var(--bg-color-dark);
    color: var(--text-color-dark);
    background-image: linear-gradient(to right, var(--bg-color-dark), var(--bg-color-darker), var(--bg-color-dark));
}
body, .container-bg, .project-card, .floating-nav ul {
    transition: all 0.5s ease;
}
.container-bg {
    background-color: var(--bg-color-darker);
}
.highlight-text {
    color: var(--highlight-color-dark);
}
.timeline-container {
    position: relative;
    padding-left: 20px;
}
.timeline-container::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: var(--highlight-color-dark);
}
.timeline-item {
    position: relative;
    padding-left: 25px;
    margin-bottom: 2rem;
    transition: transform 0.2s ease-in-out, background-color 0.2s ease-in-out;
    border-radius: 8px;
    padding: 1rem;
    cursor: pointer;
}
.timeline-item:hover {
    transform: translateY(-5px);
    background-color: rgba(79, 209, 197, 0.1);
}
@keyframes walking-dot {
    0%, 100% { transform: scale(1);
    opacity: 1; }
    50% { transform: scale(1.4); opacity: 0.7;
    }
}
.timeline-item::before {
    content: '';
    position: absolute;
    left: -8px;
    top: 1.5rem;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background-color: var(--highlight-color-dark);
    border: 2px solid var(--bg-color-darker);
    animation: walking-dot 2s infinite ease-in-out;
    transition: transform 0.2s ease-in-out;
}
.timeline-item:nth-child(2)::before { animation-delay: 0.2s; }
.timeline-item:nth-child(3)::before { animation-delay: 0.4s; }
.timeline-item:nth-child(4)::before { animation-delay: 0.6s; }
.timeline-item:nth-child(5)::before { animation-delay: 0.8s; }
.timeline-item:nth-child(6)::before { animation-delay: 1s; }
.timeline-item:nth-child(7)::before { animation-delay: 1.2s; }
.timeline-item:nth-child(8)::before { animation-delay: 1.4s; }
.timeline-item:hover::before {
    transform: scale(1.2);
    animation-play-state: paused;
}
.project-card, .certification-card {
    min-height: 150px;
    height: 100%;
    position: relative;
    overflow: hidden;
    border-radius: 12px;
    background-color: var(--card-color-dark);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 10px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out, border-color 0.3s ease-in-out;
    border: 2px solid transparent;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: flex-start;
    padding: 1rem;
}
.project-card:hover, .certification-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2), 0 15px 30px rgba(0, 0, 0, 0.15);
    border-color: var(--highlight-color-dark);
}
.project-card h3, .certification-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    transition: color 0.3s ease-in-out;
}
.project-card:hover h3, .certification-card:hover h3 {
    color: var(--highlight-color-dark);
}
.project-card p, .certification-card p {
    font-size: 0.875rem;
    margin-top: 0.25rem;
}
.project-link {
    position: relative;
    display: inline-block;
}
.project-link .tooltiptext {
    visibility: hidden;
    width: 200px;
    background-color: #555;
    color: #fff;
    text-align: center;
    border-radius: 6px;
    padding: 5px 0;
    position: absolute;
    z-index: 1;
    bottom: 125%;
    left: 50%;
    margin-left: -100px;
    opacity: 0;
    transition: opacity 0.3s;
}
.project-link:hover .tooltiptext {
    visibility: visible;
    opacity: 1;
}
@media (min-width: 640px) {
    .project-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}
@media (min-width: 1024px) {
    .project-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

.floating-nav {
    position: fixed;
    top: 50%;
    right: 0;
    transform: translateY(-50%);
    z-index: 50;
    transition: transform 0.3s ease-in-out;
}

@media (hover: hover) {
    .floating-nav:hover {
        transform: translateY(-50%) translateX(-5px);
    }
}

@media (min-width: 768px) {
    .floating-nav {
        right: auto;
        left: 0;
        transform: translateY(-50%);
    }
    
    @media (hover: hover) {
        .floating-nav:hover {
            transform: translateY(-50%) translateX(5px);
        }
    }
}

.floating-nav a {
    position: relative;
    -webkit-tap-highlight-color: transparent !important;
    outline: none !important;
}

.floating-nav a::after {
    content: attr(data-tooltip);
    position: absolute;
    right: 100%;
    top: 50%;
    transform: translateY(-50%);
    white-space: nowrap;
    padding: 0.25rem 0.5rem;
    background-color: #4A5568;
    color: white;
    border-radius: 0.25rem;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease-in-out;
    margin-right: 0.5rem;
}
@media (min-width: 768px) {
    .floating-nav a::after {
        left: 100%;
        right: auto;
        margin-left: 0.5rem;
        margin-right: 0;
    }
}
.floating-nav a:hover::after {
    opacity: 1;
}
.skill-rating {
    display: flex;
    align-items: center;
}
.skill-rating .filled-star, .skill-rating .half-star, .skill-rating .empty-star {
    color: var(--highlight-color-dark);
    margin-right: 0.25rem;
}
.skill-rating .empty-star {
    color: #4A5568;
}