:root {
    --bg-body: #121212; 
    --bg-card: #1e1e1e;
    --text-main: #e0e0e0;
    --text-muted: #a0a0a0;
    --accent: #0a80cf;
    --border-color: #333333;
}

body {
    background-color: var(--bg-body);
    color: var(--text-main);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin-right: 0px;
}

/* HEADER */
.header {
    width: 60px;
    background-color: var(--bg-card); 
    border-left: 1px solid var(--border-color);
    border-top: 1px solid var(--border-color);
    position: fixed;
    right: 0;
    bottom: 0;
    z-index: 1000;

    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 15px 5px;
}
.contact_group {
    margin-top: auto; 
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px; 
    font-size: 12px;
    color: var(--text-muted);
}
.contact_group img {
    width: 30px; 
    height: auto;
    transition: all 0.3s ease;
    cursor: pointer;
}
.contact_group img:hover {
    transform: scale(1.2);
    filter: brightness(1.5);
    filter: brightness(1.5) drop-shadow(0 0 5px var(--accent)); /* tỏa sáng nèee */
}

/* INFO */
.info {
    width: 100%;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    border-bottom: 2px solid var(--border-color);
}
.avatar img {
    width: 100%;
    height: 150px;
    border-radius: 50%;
}
.info_chitiet {
    background-color: var(--bg-card);
    width: 500px;
    min-height: 150px;
    height: auto; 
    border-radius: 12px;
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center; 
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
}
.info_chitiet p {
    padding: 25px;
    margin: 0;
    font-size: 1.05rem;
    color: var(--text-main);
    line-height: 1.8; 
    text-align: justify; 
}
.highlight-name {
    color: var(--accent);
    font-weight: bold;
    font-size: 1.2rem;
    border-bottom: 2px solid var(--accent);
}
.handle {
    color: #ffcc00; 
    font-family: 'Courier New', Courier, monospace; 
    background: rgba(255, 204, 0, 0.1);
    padding: 2px 6px;
    border-radius: 4px;
}
.school {
    font-style: italic;
    color: var(--text-muted);
    text-decoration: underline dotted;
}

/* CONTENT */
.container {
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 40px; /* Tạo khoảng cách đều giữa các mốc thời gian */
    padding-left: 60px; /* Tạo khoảng trống cho thanh dọc */
    margin: 50px auto 0;
    max-width: 700px;
}
.stick {
    position: absolute;
    width: 5px;
    background-color: var(--border-color);
    margin: 0;
    left: 20px;
    top: 0;
    bottom: 0;
    border-radius: 12px;
}
.timeline-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    position: relative;
    top: auto;
}
.dot {
    position: absolute;
    width: 25px;
    height: 25px;
    background-color: var(--border-color);
    border-radius: 50%;
    left: -50px;
    top: 0;
    z-index: 2;
}
.item-info {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.tieude {
    margin: -4px 0 0 0;
    font-size: 1.2rem;
    color: var(--text-main);
}
.noidung {
    background-color: var(--bg-card);
    padding: 15px;
    border-radius: 8px;
    border-left: 3px solid var(--accent);
    width: 100%;
    max-width: 650px;
    font-size: 0.95rem;
    color: var(--text-main);
    line-height: 1.6;
}
.noidung p {
    margin: 0;
}

.languagesNtools {
    margin-top: 50px;
    border-top: 2px solid var(--border-color);
}

/* FOOTER */
footer {
    margin-top: 50px; 
    padding: 20px 0;
    background-color: var(--bg-card);
    border-top: 1px solid var(--border-color);
    text-align: center;
}
.footer-content p {
    margin: 5px 0;
    color: var(--text-muted);
    font-size: 0.9rem;
}
.security-note {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.8rem !important;
    opacity: 0.6;
    letter-spacing: 1px;
}

/* Tối ưu cho Mobile */
@media (max-width: 768px) {
    /* 1. Phần giới thiệu: Chuyển sang dạng dọc */
    .info {
        flex-direction: column;
        height: auto;
        padding: 30px 10px;
        gap: 25px;
        border-bottom: 1px solid var(--border-color);
    }

    .info_chitiet {
        width: 90%;
        max-width: 400px;
    }

    .info_chitiet p {
        padding: 20px;
        font-size: 0.95rem;
    }

    /* 2. Sửa lỗi dòng thời gian bị chồng chéo (Dính nội dung) */
    .container {
        max-width: 90%;
        padding-left: 50px;
        margin-top: 30px;
    }

    .stick {
        left: 15px;
        height: 100%;
    }

    .timeline-item {
        position: relative;
        left: 0;               
    }

    .dot {
        width: 20px;
        height: 20px;
        left: -42px;
    }

    .noidung {
        width: calc(100vw - 80px);
        font-size: 0.9rem;
        padding: 12px;
    }

    /* 3. Tiêu đề chính */
    h1 {
        font-size: 1.5rem;
        text-align: center;
        padding: 10px;
    }

    /* 4. Nhóm liên hệ (Header) */
    .header {
        width: 50px;
        padding: 10px 0;
    }

    .contact_group img {
        width: 25px;
    }

    /* 5. Footer */
    footer {
        padding: 30px 20px;
        margin-top: 60px;
    }

    /* khacs */
    .languagesNtools {
        margin-top: 30px;
        border-top: 1px solid var(--border-color);
    }
}