/* ============================================
   Drake Theme - Light (default)
   Based on Typora Drake theme by liangjingkanji
   ============================================ */
:root,
[data-theme="light"] {
    --text-color: #333333;
    --bg-color: #ffffff;
    --sidebar-bg: #fafafa;
    --top-bar-bg: #ffffff;
    --drake-accent: #e95f59;
    --drake-highlight: #d63200;
    --a-color: #d63200;
    --title-color: #273849;
    --code-block-bg-color: #2b2b2b;
    --code-block-color: #A9B7C6;
    --inline-code-color: #d63200;
    --blockquote-border-color: #e95f59;
    --blockquote-color: #333333;
    --blockquote-bg-color: #fdefee;
    --strong-color: #273849;
    --horizontal-divider-color: #273849;
    --table-border-color: #dfe2e5;
    --table-header-bg-color: #f8f8f8;
    --table-n2-bg-color: #f8f8f8;
    --item-hover-bg-color: #E5E5E596;
    --sidebar-item-active: #e95f59;
    --sidebar-border: #e0e0e0;
    --shadow-color: rgba(0,0,0,0.08);
    --scrollbar-track: #f1f1f1;
    --scrollbar-thumb: #c1c1c1;
    --yaml-color: #777777;
    --yaml-bg-color: #f7f7f7;
    --kbd-border: #5b5b5e;
}

/* ============================================
   Drake Black Theme - Dark
   Based on Typora Drake-black theme
   ============================================ */
[data-theme="dark"] {
    --text-color: #b3bec4;
    --bg-color: #212121;
    --sidebar-bg: #1b1b1b;
    --top-bar-bg: #212121;
    --drake-accent: #ff9800;
    --drake-highlight: #ff9800;
    --a-color: #ff9800;
    --title-color: #bbc6d2;
    --code-block-bg-color: #1b1b1b;
    --code-block-color: #b3bec4;
    --inline-code-color: #ff9800;
    --blockquote-border-color: #ff9800;
    --blockquote-color: #b3bec4;
    --blockquote-bg-color: rgba(255, 185, 82, 0.05);
    --strong-color: #bbc6d2;
    --horizontal-divider-color: #bbc6d2;
    --table-border-color: #323232;
    --table-header-bg-color: #292929;
    --table-n2-bg-color: #292929;
    --item-hover-bg-color: #323232;
    --sidebar-item-active: #ff9800;
    --sidebar-border: #2d2d2d;
    --shadow-color: rgba(0,0,0,0.3);
    --scrollbar-track: #2a2a2a;
    --scrollbar-thumb: #4a4a4a;
    --yaml-color: #676773;
    --yaml-bg-color: #1b1b1b;
    --kbd-border: #5b5b5e;
}

/* ============================================
   Base & Reset
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
}
::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--drake-accent);
}

/* ============================================
   Layout
   ============================================ */
.app-container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 280px;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--sidebar-border);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 100;
    transition: transform 0.3s ease, background-color 0.3s;
    overflow: hidden;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--sidebar-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-shrink: 0;
}

.site-title {
    font-size: 1.2rem;
    color: var(--title-color);
    font-weight: 700;
}

.sidebar-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--text-color);
    padding: 4px 8px;
    border-radius: 4px;
}
.sidebar-toggle:hover {
    background: var(--item-hover-bg-color);
}

.sidebar-nav {
    flex: 1;
    overflow-y: auto;
    padding: 12px 0;
}

.course-section {
    margin-bottom: 8px;
}

.course-title {
    padding: 10px 20px;
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--title-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    user-select: none;
    border-radius: 4px;
    margin: 0 8px;
}
.course-title:hover {
    background: var(--item-hover-bg-color);
}

.course-arrow {
    transition: transform 0.2s;
    font-size: 0.7rem;
}
.course-section.collapsed .course-arrow {
    transform: rotate(-90deg);
}

.lesson-list {
    list-style: none;
    padding: 4px 0;
}
.course-section.collapsed .lesson-list {
    display: none;
}

.lesson-item {
    display: block;
    padding: 8px 20px 8px 44px;
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.9rem;
    cursor: pointer;
    border-left: 3px solid transparent;
    transition: all 0.15s;
    line-height: 1.4;
}
.lesson-item:hover {
    background: var(--item-hover-bg-color);
}
.lesson-item.active {
    color: var(--sidebar-item-active);
    border-left-color: var(--sidebar-item-active);
    background: var(--item-hover-bg-color);
    font-weight: 600;
}

/* Main content */
.main-content {
    flex: 1;
    margin-left: 280px;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: margin-left 0.3s;
}

.top-bar {
    height: 56px;
    background: var(--top-bar-bg);
    border-bottom: 1px solid var(--sidebar-border);
    display: flex;
    align-items: center;
    padding: 0 24px;
    gap: 16px;
    position: sticky;
    top: 0;
    z-index: 50;
    transition: background-color 0.3s;
}

.menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.3rem;
    cursor: pointer;
    color: var(--text-color);
    padding: 4px 8px;
    border-radius: 4px;
}
.menu-btn:hover {
    background: var(--item-hover-bg-color);
}

.breadcrumb {
    flex: 1;
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
}

.top-bar-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

.theme-toggle {
    background: none;
    border: 1px solid var(--sidebar-border);
    border-radius: 20px;
    padding: 6px 14px;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text-color);
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 4px;
}
.theme-toggle:hover {
    background: var(--item-hover-bg-color);
    border-color: var(--drake-accent);
}
[data-theme="light"] .theme-icon-dark { display: none; }
[data-theme="dark"] .theme-icon-light { display: none; }

.content-area {
    flex: 1;
    padding: 40px 60px 80px;
    max-width: 960px;
    width: 100%;
    margin: 0 auto;
}

/* Sidebar overlay for mobile */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    z-index: 99;
}
.sidebar-overlay.show {
    display: block;
}

/* ============================================
   Welcome Page
   ============================================ */
.welcome-page {
    text-align: center;
    padding: 40px 0;
}
.welcome-page h1 {
    font-size: 2.2rem;
    color: var(--title-color);
    margin-bottom: 16px;
}
.welcome-desc {
    font-size: 1.1rem;
    color: var(--text-color);
    opacity: 0.8;
    margin-bottom: 48px;
}

.course-cards {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 20px;
    text-align: left;
}

.course-card {
    background: var(--sidebar-bg);
    border: 1px solid var(--sidebar-border);
    border-radius: 12px;
    padding: 24px;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    color: var(--text-color);
    display: block;
}
.course-card:hover {
    border-color: var(--drake-accent);
    box-shadow: 0 4px 16px var(--shadow-color);
    transform: translateY(-2px);
}
.course-card-icon {
    font-size: 2rem;
    margin-bottom: 12px;
}
.course-card-title {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--title-color);
    margin-bottom: 8px;
}
.course-card-desc {
    font-size: 0.9rem;
    opacity: 0.7;
    line-height: 1.5;
}
.course-card-count {
    margin-top: 12px;
    font-size: 0.8rem;
    color: var(--drake-accent);
    font-weight: 600;
}

/* ============================================
   Markdown Content Styles (Drake theme)
   ============================================ */
#write {
    max-width: 100%;
}

#write h1,
#write h2,
#write h3,
#write h4,
#write h5,
#write h6 {
    font-weight: 700;
    line-height: 1.4;
    color: var(--title-color);
    margin-top: 2rem;
    margin-bottom: 1rem;
}

#write h1 {
    font-size: 2rem;
    text-align: center;
    margin-top: 0;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--drake-accent);
}

#write h2 {
    font-size: 1.6rem;
    padding-bottom: 0.3rem;
    border-bottom: 1px solid var(--horizontal-divider-color);
}

#write h3 {
    font-size: 1.3rem;
}

#write h4 {
    font-size: 1.15rem;
}

#write h5 {
    font-size: 1rem;
}

#write h6 {
    font-size: 0.95rem;
    opacity: 0.8;
}

#write p {
    margin: 1rem 0;
    line-height: 1.8;
}

#write a {
    color: var(--a-color);
    text-decoration: none;
    border-bottom: 1px solid var(--a-color);
}
#write a:hover {
    opacity: 0.8;
}

#write strong {
    color: var(--strong-color);
    font-weight: 700;
}

#write em {
    font-style: italic;
}

#write ul,
#write ol {
    padding-left: 2em;
    margin: 1rem 0;
}

#write li {
    margin: 0.5em 0;
    line-height: 1.7;
}

#write li > ul,
#write li > ol {
    margin: 0.3em 0;
}

/* Blockquote */
#write blockquote {
    color: var(--blockquote-color);
    border-radius: 4px;
    padding: 12px 20px;
    background-color: var(--blockquote-bg-color);
    position: relative;
    margin: 1.2rem 0;
    border-left: 4px solid var(--blockquote-border-color);
}
#write blockquote p {
    margin: 0.4rem 0;
}
#write blockquote strong {
    color: var(--blockquote-color);
}

/* Code */
#write code {
    margin: 0 2px;
    padding: 2px 6px;
    color: var(--inline-code-color);
    background: var(--item-hover-bg-color);
    border-radius: 3px;
    font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, Monaco, monospace;
    font-size: 0.9em;
}

#write pre {
    background-color: var(--code-block-bg-color);
    color: var(--code-block-color);
    padding: 1rem;
    border-radius: 4px;
    overflow-x: auto;
    margin: 1rem 0;
    line-height: 1.5;
}
#write pre code {
    background: none;
    color: inherit;
    padding: 0;
    margin: 0;
    font-size: 0.9rem;
}

/* Horizontal rule */
#write hr {
    height: 2px;
    padding: 0;
    margin: 24px 0;
    background-color: var(--horizontal-divider-color);
    border: 0 none;
    border-radius: 1px;
}

/* Table */
#write table {
    margin: 1rem 0;
    border-collapse: collapse;
    width: 100%;
    background-color: var(--bg-color);
    border: 1px solid var(--table-border-color);
    border-radius: 4px;
    overflow: hidden;
}
#write th {
    font-weight: 700;
    border: 1px solid var(--table-border-color);
    padding: 10px 16px;
    background-color: var(--table-header-bg-color);
    color: var(--title-color);
    text-align: left;
}
#write td {
    border: 1px solid var(--table-border-color);
    padding: 10px 16px;
}
#write tr:nth-child(2n) {
    background-color: var(--table-n2-bg-color);
}

/* Images */
#write img {
    max-width: 100%;
    border-radius: 4px;
    display: block;
    margin: 1rem auto;
}

/* Mark / highlight */
#write mark {
    border: 1px solid var(--drake-highlight);
    color: var(--drake-highlight);
    background-color: transparent;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.95em;
}

/* Keyboard */
#write kbd {
    border: 1px solid var(--kbd-border);
    background: transparent;
    color: var(--text-color);
    font-family: inherit;
    font-size: 0.9em;
    padding: 3px 6px;
    border-radius: 4px;
    box-shadow: 1px 1px 2px rgba(0,0,0,0.3);
}

/* Task list */
#write input[type="checkbox"] {
    margin-right: 8px;
    accent-color: var(--drake-accent);
}

/* KaTeX adjustments */
.katex {
    font-size: 1.1em;
}
.katex-display {
    margin: 1.2rem 0 !important;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 4px 0;
}

/* YAML / meta block */
#write pre.md-meta-block {
    padding: 1rem;
    font-size: 0.9rem;
    line-height: 1.5;
    background-color: var(--yaml-bg-color);
    border: 0;
    border-radius: 4px;
    color: var(--yaml-color);
}

/* Loading */
.loading {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-color);
    opacity: 0.6;
    font-size: 1rem;
}
.loading::after {
    content: "";
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--drake-accent);
    border-top-color: transparent;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-left: 10px;
    vertical-align: middle;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }
    .sidebar.show {
        transform: translateX(0);
    }
    .main-content {
        margin-left: 0;
    }
    .menu-btn {
        display: block;
    }
    .sidebar-toggle {
        display: block;
    }
    .content-area {
        padding: 24px 20px 60px;
    }
    .top-bar {
        padding: 0 16px;
    }
    .welcome-page h1 {
        font-size: 1.6rem;
    }
    .course-cards {
        grid-template-columns: 1fr;
    }
}

/* Print */
@media print {
    .sidebar, .top-bar, .sidebar-overlay {
        display: none !important;
    }
    .main-content {
        margin-left: 0;
    }
    .content-area {
        padding: 0;
    }
}