body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #121212;
    color: #ffffff;
    text-align: center;
}

header {
    background-color: #1f1f1f;
    padding: 10px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
}

nav ul li {
    margin: 0 15px;
}

nav ul li a {
    color: #ffffff;
    text-decoration: none;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: #f39c12;
}

.header-buttons {
    display: flex;
    align-items: center;
}

.header-buttons button {
    background-color: transparent;
    border: none;
    color: #ffffff;
    cursor: pointer;
    margin-left: 10px;
    font-size: 1em;
}

.header-buttons button i {
    font-size: 1.5em;
}

.header-buttons button:hover {
    color: #f39c12;
}

section {
    padding: 100px 20px;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

#welcome {
    background-color: #1f1f1f;
    color: #ffffff;
    text-align: center;
}

.welcome-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
}

.welcome-link {
    color: #f39c12;
    text-decoration: none;
    font-size: 1.2em;
    margin: 10px;
    transition: color 0.3s;
}

.welcome-link:hover {
    color: #ffffff;
}

.content {
    max-width: 800px;
    margin: 0 auto;
}

.project {
    margin: 20px 0;
}

footer {
    background-color: #1f1f1f;
    color: #ffffff;
    padding: 20px 0;
    text-align: center;
    position: relative;
    bottom: 0;
    width: 100%;
}

.timeline {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.timeline-item {
    background-color: #282828;
    padding: 20px;
    margin: 10px 0;
    width: 80%;
    border-radius: 5px;
    text-align: left;
}

.timeline-item .date {
    font-weight: bold;
    margin-bottom: 5px;
}

.hidden {
    opacity: 0;
    transform: translateY(50px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

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

/* 반응형 디자인 */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        align-items: flex-start;
    }

    nav ul {
        flex-direction: column;
        align-items: flex-start;
    }

    nav ul li {
        margin: 10px 0;
    }

    .header-buttons {
        margin-top: 10px;
        justify-content: flex-end;
        width: 100%;
    }
}

@media (max-width: 480px) {
    .header-buttons button {
        font-size: 0.8em;
    }

    .header-buttons button i {
        font-size: 1.2em;
    }

    section {
        padding: 20px 10px;
    }
}