/*
 * HTML Book Module - Sidebar Navigation
 * Collapsible category navigation with active state highlighting
 */

/* Sidebar Container */
.sidebar-nav {
    list-style: none;
    padding: 0;
    margin: 0;
}

/* Category Item */
.category-item {
    margin-bottom: 10px;
}

/* Category Toggle Button */
.category-toggle {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 15px;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-speed);
    font-family: 'Sylfaen', 'Arial', sans-serif;
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    text-align: left;
}

.category-toggle:hover {
    background-color: var(--accent);
    color: white;
    transform: translateX(3px);
}

.category-toggle:active {
    transform: translateX(3px) scale(0.98);
}

/* Category Icon */
.category-icon {
    width: 20px;
    height: 20px;
    margin-right: 10px;
    display: inline-block;
    vertical-align: middle;
}

/* Category Name */
.category-name {
    flex: 1;
    display: flex;
    align-items: center;
}

/* Tag Counter */
.tag-counter {
    font-size: 12px;
    font-weight: 500;
    background-color: var(--accent);
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    margin-left: 8px;
}

.category-toggle:hover .tag-counter {
    background-color: white;
    color: var(--accent);
}

/* Expand/Collapse Arrow */
.category-arrow {
    width: 0;
    height: 0;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-top: 6px solid var(--text-secondary);
    transition: transform var(--transition-speed);
    margin-left: 10px;
}

.category-toggle:hover .category-arrow {
    border-top-color: white;
}

.category-item.expanded .category-arrow {
    transform: rotate(180deg);
}

/* Tag List */
.tag-list {
    list-style: none;
    padding: 0;
    margin: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-speed) ease-out;
}

.category-item.expanded .tag-list {
    max-height: 1000px;
    transition: max-height var(--transition-speed) ease-in;
}

/* Tag List Item */
.tag-list-item {
    margin: 0;
}

/* Tag Link */
.tag-link {
    display: block;
    padding: 8px 15px 8px 35px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    transition: all var(--transition-speed);
    border-left: 3px solid transparent;
    position: relative;
}

.tag-link:before {
    content: '<>';
    position: absolute;
    left: 15px;
    color: var(--text-muted);
    font-family: 'Courier New', monospace;
    font-size: 12px;
}

.tag-link:hover {
    background-color: var(--bg-tertiary);
    color: var(--accent);
    border-left-color: var(--accent);
    padding-left: 40px;
}

.tag-link:hover:before {
    color: var(--accent);
}

/* Active Tag */
.tag-link.active {
    background-color: var(--accent);
    color: white;
    font-weight: 600;
    border-left-color: var(--accent-hover);
}

.tag-link.active:before {
    color: white;
}

/* Search Box in Sidebar */
.sidebar-search {
    margin-bottom: var(--spacing-unit);
}

.sidebar-search-input {
    width: 100%;
    padding: 10px 15px;
    font-size: 14px;
    font-family: 'Sylfaen', 'Arial', sans-serif;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
}

.sidebar-search-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(0, 149, 221, 0.1);
}

.sidebar-search-input::placeholder {
    color: var(--text-muted);
}

/* Progress Tracker */
.progress-tracker {
    margin-top: var(--spacing-unit);
    padding: 15px;
    background-color: var(--bg-tertiary);
    border-radius: 8px;
}

.progress-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
    display: flex;
    justify-content: space-between;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--bg-secondary);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    border-radius: 4px;
    transition: width 0.5s ease;
}

/* Sidebar Footer */
.sidebar-footer {
    margin-top: var(--spacing-unit);
    padding-top: var(--spacing-unit);
    border-top: 1px solid var(--border-color);
    font-size: 12px;
    color: var(--text-muted);
    text-align: center;
}

/* Hamburger Menu Button (Mobile) */
.hamburger-btn {
    display: none;
    flex-direction: column;
    justify-content: space-around;
    width: 30px;
    height: 25px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1100;
}

.hamburger-line {
    width: 100%;
    height: 3px;
    background-color: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-speed);
}

.hamburger-btn.open .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translateY(10px);
}

.hamburger-btn.open .hamburger-line:nth-child(2) {
    opacity: 0;
}

.hamburger-btn.open .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translateY(-10px);
}

/* Sidebar Overlay for Mobile */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    transition: opacity var(--transition-speed);
}

.sidebar-overlay.visible {
    display: block;
    opacity: 1;
}

/* Search Highlight */
.search-highlight {
    background-color: #ffeb3b;
    color: #000;
    padding: 2px 4px;
    border-radius: 2px;
}

/* No Results Message */
.no-results {
    padding: 20px;
    text-align: center;
    color: var(--text-muted);
    font-size: 14px;
}