:root {
    --primary: #1A89FA;
    --primary-dark: #3a56c5;
    --secondary: #6c757d;
    --success: #73d13d;
    --warning: #FC9416;
    --danger: #dc3545;
    --light: #f8f9fa;
    --dark: #343a40;
    --white: #ffffff;
    --border: #e9ecef;
    --shadow: rgba(0,0,0,0.1);
    --radius: 8px;
    --transition: 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: var(--white);
    padding-top: 80px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Fixed Header */
header {
    background: var(--white);
    box-shadow: 0 2px 10px var(--shadow);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo h1 {
    font-weight: 400;
    font-size: 22px;
    color: #303133;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo h1 img {
    width: 88px;
    height: 37px;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
    align-items: center;
}

nav a {
    color: var(--dark);
    text-decoration: none;
    font-weight: 500;
    padding: 5px 0;
    position: relative;
    transition: var(--transition);
}

nav a:hover, nav a.active {
    color: var(--primary);
}

nav a.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--primary);
    border-radius: 3px;
}

/* Language Selector */
.lang-selector select {
    padding: 5px 10px;
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--white);
    color: var(--dark);
    font-size: 0.9rem;
    cursor: pointer;
}

/* Manual Layout with Left Sidebar */
.manual-container {
    position: relative;
}

.table-of-contents {
    position: fixed;
    top: 80px;
    left: 20px;
    width: 280px;
    height: calc(100vh - 80px);
    background: var(--white);
    border-right: 1px solid var(--border);
    padding: 20px;
    box-shadow: 2px 0 10px var(--shadow);
    overflow-y: auto;
    z-index: 90;
}

.table-of-contents h4 {
    color: var(--primary);
    margin-bottom: 15px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--border);
}

.toc-list {
    list-style: none;
}

.toc-list li {
    margin-bottom: 8px;
}

.toc-list a {
    display: block;
    padding: 8px 12px;
    color: var(--dark);
    text-decoration: none;
    border-radius: 4px;
    font-size: 0.9rem;
    transition: var(--transition);
    border-left: 3px solid transparent;
}

.toc-list a:hover {
    background: var(--light);
    color: var(--primary);
    border-left-color: var(--primary);
}

.toc-list a.active {
    background: var(--primary);
    color: var(--white);
    border-left-color: var(--primary-dark);
}

.toc-sub {
    margin-left: 15px;
}

.manual-content {
    margin-left: 320px;
    padding: 40px 20px;
}

.manual-content h3 {
    color: var(--primary);
    margin: 30px 0 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border);
}

.manual-content img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius);
    box-shadow: 0 3px 15px var(--shadow);
    margin: 20px 0;
}

/* Version Selector */
.version-selector {
    text-align: center;
    margin-bottom: 40px;
}

.version-selector select {
    padding: 8px 15px;
    border: 2px solid var(--border);
    border-radius: 20px;
    background: var(--white);
    color: var(--dark);
    font-size: 0.9rem;
    cursor: pointer;
}

#versionSelect {
    padding: 10px 15px;
    border: 2px solid var(--border);
    border-radius: 20px;
    background: var(--white);
    color: var(--dark);
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
    transition: var(--transition);
}

#versionSelect:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(74, 108, 247, 0.1);
}

/* FAQ */
.faq-item {
    background: var(--white);
    border-radius: var(--radius);
    margin-bottom: 15px;
    box-shadow: 0 2px 10px var(--shadow);
    overflow: hidden;
}

.faq-question {
    background: var(--light);
    padding: 20px;
    cursor: pointer;
    font-weight: 500;
    position: relative;
    transition: var(--transition);
}

.faq-question:hover {
    background: var(--primary);
    color: var(--white);
}

.faq-question::after {
    content: '\f107';
    font-family: 'Font Awesome 5 Free';
    font-weight: 900;
    position: absolute;
    right: 20px;
    transition: var(--transition);
}

.faq-question.active::after {
    transform: rotate(180deg);
}

.faq-answer {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}
.faq-answer ol, .faq-answer ul {
    padding-left: 20px;
}
.faq-answer.active {
    padding: 20px;
    max-height: fit-content;
}

/* Search */
.search-box {
    max-width: 500px;
    margin: 0 auto 40px;
    position: relative;
}

.search-box input {
    width: 100%;
    padding: 12px 45px 12px 15px;
    border: 2px solid var(--border);
    border-radius: 25px;
    font-size: 1rem;
    outline: none;
    transition: var(--transition);
}

.search-box input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(74, 108, 247, 0.1);
}

.search-box i {
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--secondary);
}

/* Changelog */
.version-item {
    background: var(--white);
    border-radius: var(--radius);
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 2px 10px var(--shadow);
}

.version-header {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
    gap: 15px;
}

.version-number {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary);
}

.version-date {
    color: var(--secondary);
}

.version-tag {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
}

.tag-major { background: var(--danger); color: var(--white); }
.tag-minor { background: var(--primary); color: var(--white); }
.tag-patch { background: var(--success); color: var(--white); }

.change-list {
    list-style: none;
}

.change-item {
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: flex-start;
    gap: 10px;
}

.change-item:last-child {
    border-bottom: none;
}

.change-type {
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    flex-shrink: 0;
}

.type-new { background: var(--primary); color: var(--white); }
.type-improved { background: var(--success); color: var(--white); }
.type-fixed { background: var(--warning); color: var(--white); }

/* Utilities */
.tip, .warning {
    padding: 15px 20px;
    margin: 20px 0;
    border-radius: var(--radius);
    border-left: 4px solid;
}

.tip {
    background: rgba(74, 108, 247, 0.1);
    border-left-color: var(--primary);
}

.warning {
    background: rgba(220, 53, 69, 0.1);
    border-left-color: var(--danger);
}

/* Footer */
footer {
    background: var(--dark);
    color: var(--white);
    text-align: center;
    padding: 30px 0;
    margin-top: 60px;
}

/* Mobile Responsive */
@media (max-width: 992px) {
    .table-of-contents {
        position: fixed;
        top: 0;
        left: -300px;
        width: 280px;
        height: 100vh;
        z-index: 99;
        transition: left var(--transition);
    }
    
    .table-of-contents.mobile-active {
        left: 0;
    }
    
    .manual-content {
        margin-left: 0;
    }
    
    .toc-toggle {
        display: flex;
        position: fixed;
        top: 50%;
        left: 20px;
        transform: translateY(-50%);
        width: 50px;
        height: 50px;
        border-radius: 50%;
        background: var(--primary);
        color: var(--white);
        border: none;
        cursor: pointer;
        font-size: 1.2rem;
        box-shadow: 0 3px 10px var(--shadow);
        z-index: 98;
        align-items: center;
        justify-content: center;
    }
}

@media (max-width: 768px) {
    header .container {
        flex-direction: column;
        gap: 15px;
    }
    
    nav ul {
        gap: 20px;
    }
    
    .table-of-contents {
        width: 100%;
        left: -100%;
    }
}