/* ========== CSS Variables / 主题 ========== */
:root {
    --bg-primary: #4f46e5;
    --bg-primary-hover: #4338ca;
    --bg-body: #f8f9fa;
    --bg-card: #ffffff;
    --bg-nav: #ffffff;
    --bg-footer: #1f2937;
    --bg-code: #f1f5f9;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-hover: 0 4px 12px rgba(0,0,0,0.12);
    --radius: 8px;
    --transition: all 0.2s ease;
}

[data-theme="dark"] {
    --bg-body: #111827;
    --bg-card: #1f2937;
    --bg-nav: #1f2937;
    --bg-footer: #0f172a;
    --bg-code: #334155;
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-muted: #9ca3af;
    --border-color: #374151;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-hover: 0 4px 12px rgba(0,0,0,0.4);

    /* Override Bootstrap classes in dark mode */
    --bs-body-bg: #111827;
    --bs-body-color: #f9fafb;
    --bs-card-bg: #1f2937;
    --bs-border-color: #374151;
    --bs-modal-bg: #1f2937;
    --bs-tertiary-bg: #334155;
    --bs-secondary-bg: #1f2937;
}

/* Dark mode Bootstrap overrides */
[data-theme="dark"] .bg-light { background: var(--bg-code) !important; }
[data-theme="dark"] .text-dark { color: var(--text-primary) !important; }
[data-theme="dark"] .text-muted { color: var(--text-muted) !important; }
[data-theme="dark"] .border { border-color: var(--border-color) !important; }
[data-theme="dark"] .border-top { border-top-color: var(--border-color) !important; }
[data-theme="dark"] .border-bottom { border-bottom-color: var(--border-color) !important; }
[data-theme="dark"] .border-start { border-left-color: var(--border-color) !important; }
[data-theme="dark"] .border-end { border-right-color: var(--border-color) !important; }
[data-theme="dark"] .btn-close { filter: invert(1) grayscale(100%) brightness(200%); }
[data-theme="dark"] .modal-content { background: var(--bg-card); border-color: var(--border-color); }
[data-theme="dark"] .modal-header { border-bottom-color: var(--border-color); }
[data-theme="dark"] .modal-footer { border-top-color: var(--border-color); }
[data-theme="dark"] .nav-tabs { border-bottom-color: var(--border-color); }
[data-theme="dark"] .nav-tabs .nav-link { color: var(--text-secondary); border-color: transparent; }
[data-theme="dark"] .nav-tabs .nav-link.active { background: var(--bg-card); color: var(--text-primary); border-color: var(--border-color) var(--border-color) transparent; }
[data-theme="dark"] .input-group-text { background: var(--bg-code); color: var(--text-secondary); border-color: var(--border-color); }
[data-theme="dark"] .list-group-item { background: var(--bg-card); border-color: var(--border-color); color: var(--text-primary); }
[data-theme="dark"] .breadcrumb-item a { color: var(--text-secondary); }
[data-theme="dark"] .breadcrumb-item.active { color: var(--text-muted); }
[data-theme="dark"] hr { border-color: var(--border-color); }
[data-theme="dark"] .btn-light { background: var(--bg-code); border-color: var(--border-color); color: var(--text-primary); }
[data-theme="dark"] .btn-light:hover { background: var(--border-color); }
[data-theme="dark"] .btn-outline-secondary { color: var(--text-secondary); border-color: var(--border-color); }
[data-theme="dark"] .btn-outline-secondary:hover { background: var(--bg-code); color: var(--text-primary); border-color: var(--border-color); }
[data-theme="dark"] .btn-secondary { background: var(--bg-code); border-color: var(--border-color); color: var(--text-primary); }
[data-theme="dark"] .progress { background: var(--bg-code); }
[data-theme="dark"] .placeholder { background: var(--bg-code); }
[data-theme="dark"] .card-body hr { border-color: var(--border-color); }
[data-theme="dark"] .text-bg-light { background: var(--bg-code) !important; color: var(--text-primary) !important; }

/* Quill editor dark mode */
[data-theme="dark"] .ql-toolbar.ql-snow { border-color: var(--border-color); background: var(--bg-card); }
[data-theme="dark"] .ql-container.ql-snow { border-color: var(--border-color); background: var(--bg-card); color: var(--text-primary); }
[data-theme="dark"] .ql-snow .ql-stroke { stroke: var(--text-secondary); }
[data-theme="dark"] .ql-snow .ql-fill { fill: var(--text-secondary); }
[data-theme="dark"] .ql-snow .ql-picker { color: var(--text-secondary); }
[data-theme="dark"] .ql-snow .ql-picker-options { background: var(--bg-card); border-color: var(--border-color); }
[data-theme="dark"] .ql-editor.ql-blank::before { color: var(--text-muted); }

/* Markdown preview dark mode */
[data-theme="dark"] #markdown-preview { background: var(--bg-code) !important; color: var(--text-primary); }
[data-theme="dark"] #markdown-preview code { background: var(--bg-card); }
[data-theme="dark"] #markdown-preview pre { background: var(--bg-card); }
[data-theme="dark"] #markdown-preview blockquote { background: var(--bg-card); border-left-color: var(--bg-primary); }
[data-theme="dark"] #markdown-preview table th { background: var(--bg-card); }
[data-theme="dark"] #markdown-preview table td, [data-theme="dark"] #markdown-preview table th { border-color: var(--border-color); }

/* ========== Base ========== */
* { box-sizing: border-box; }
body {
    background: var(--bg-body);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background 0.3s, color 0.3s;
}
a { color: var(--bg-primary); }
a:hover { color: var(--bg-primary-hover); }
::selection { background: var(--bg-primary); color: #fff; }

/* ========== Navbar ========== */
.navbar {
    background: var(--bg-nav) !important;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    padding: 0.5rem 0;
    z-index: 1030;
}
.navbar-brand {
    font-weight: 700;
    font-size: 1.3rem;
    color: var(--bg-primary) !important;
}
.navbar-brand i { font-size: 1.5rem; }
.nav-link {
    color: var(--text-secondary) !important;
    font-weight: 500;
    transition: var(--transition);
}
.nav-link:hover, .nav-link.active { color: var(--bg-primary) !important; }
.theme-toggle {
    border: none;
    font-size: 1.1rem;
    cursor: pointer;
}
.nav-btn { margin-left: 0.5rem; }

.search-form { max-width: 280px; }
.search-form .form-control {
    border-radius: 20px 0 0 20px;
    background: var(--bg-body);
    border-color: var(--border-color);
    color: var(--text-primary);
}
.search-form .btn { border-radius: 0 20px 20px 0; }

/* ========== Cards ========== */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.card:hover { box-shadow: var(--shadow-hover); }
.card-header {
    background: transparent;
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
    padding: 0.75rem 1rem;
}

/* ========== Article Cards ========== */
.article-card { transition: var(--transition); }
.article-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-hover); }
.article-card .card-title a {
    color: var(--text-primary);
    font-weight: 600;
    text-decoration: none;
}
.article-card .card-title a:hover { color: var(--bg-primary); }
.article-thumb {
    width: 120px;
    height: 80px;
    object-fit: cover;
    border-radius: 6px;
}
.summary { font-size: 0.9rem; }
.article-meta { font-size: 0.85rem; }

/* ========== Avatar ========== */
.avatar-xs { width: 24px; height: 24px; border-radius: 50%; object-fit: cover; }
.avatar-sm { width: 32px; height: 32px; border-radius: 50%; object-fit: cover; }
.avatar-lg { width: 80px; height: 80px; border-radius: 50%; object-fit: cover; border: 3px solid var(--border-color); }

/* ========== Featured Section ========== */
.featured-section { overflow: hidden; }
.featured-item { display: block; padding: 1rem; color: var(--text-primary); }
.featured-img {
    width: 100%;
    max-height: 300px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 1rem;
}
.featured-info h4 { font-weight: 700; }

/* ========== Article Page ========== */
.article-title {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}
.article-content {
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-primary);
}
.article-content h1, .article-content h2, .article-content h3,
.article-content h4, .article-content h5 {
    margin-top: 1.5em;
    margin-bottom: 0.5em;
    font-weight: 700;
}
.article-content h1 { font-size: 1.6rem; border-bottom: 2px solid var(--border-color); padding-bottom: 0.3em; }
.article-content h2 { font-size: 1.4rem; border-bottom: 1px solid var(--border-color); padding-bottom: 0.3em; }
.article-content h3 { font-size: 1.2rem; }
.article-content p { margin-bottom: 1em; }
.article-content img { max-width: 100%; height: auto; border-radius: 6px; margin: 1em 0; }
.article-content pre {
    background: var(--bg-code);
    padding: 1rem;
    border-radius: 6px;
    overflow-x: auto;
    font-size: 0.9rem;
}
.article-content code {
    background: var(--bg-code);
    padding: 0.15em 0.4em;
    border-radius: 3px;
    font-size: 0.9em;
}
.article-content pre code { background: none; padding: 0; }
.article-content blockquote {
    border-left: 4px solid var(--bg-primary);
    padding: 0.5em 1em;
    margin: 1em 0;
    color: var(--text-secondary);
    background: var(--bg-code);
    border-radius: 0 6px 6px 0;
}
.article-content table { width: 100%; border-collapse: collapse; margin: 1em 0; }
.article-content th, .article-content td {
    border: 1px solid var(--border-color);
    padding: 0.5em 0.8em;
    text-align: left;
}
.article-content th { background: var(--bg-code); font-weight: 600; }
.article-content a { color: var(--bg-primary); text-decoration: underline; }
.article-content ul, .article-content ol { padding-left: 1.5em; margin-bottom: 1em; }
.article-content li { margin-bottom: 0.3em; }

/* ========== Actions ========== */
.btn-action {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    border-radius: 20px;
    font-size: 0.9rem;
}

/* ========== Sidebar ========== */
.sidebar-card .card-header { font-size: 0.95rem; }
.tag-link {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    background: var(--bg-code);
    border-radius: 12px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    transition: var(--transition);
}
.tag-link:hover {
    background: var(--bg-primary);
    color: #fff;
}

/* ========== Auth Pages ========== */
.auth-card {
    margin-top: 3rem;
    border-radius: 12px;
}
.auth-card .form-control {
    padding: 0.6rem 0.8rem;
    border-radius: 8px;
}
.auth-card .form-control:focus {
    border-color: var(--bg-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

/* ========== Comments ========== */
.comment-item { transition: var(--transition); }
.comment-item:hover { background: var(--bg-code); border-radius: 6px; }

/* ========== Editor ========== */
#markdown-input {
    border-radius: 0 0 0 4px;
    resize: none;
    font-size: 0.95rem;
    line-height: 1.6;
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--border-color);
}

/* ========== Footer ========== */
.footer {
    background: var(--bg-footer);
    color: #d1d5db;
    margin-top: auto;
}
.footer a { color: #93c5fd; }

/* ========== Toast ========== */
.toast-container { z-index: 9999; }

/* ========== Notification Badge ========== */
.notification-badge {
    position: absolute;
    top: 2px;
    right: 2px;
    font-size: 0.65rem;
    padding: 0.15em 0.4em;
}

/* ========== Pagination ========== */
.page-link { color: var(--bg-primary); }
.page-item.active .page-link {
    background: var(--bg-primary);
    border-color: var(--bg-primary);
}

/* ========== Buttons ========== */
.btn-primary {
    background: var(--bg-primary);
    border-color: var(--bg-primary);
}
.btn-primary:hover {
    background: var(--bg-primary-hover);
    border-color: var(--bg-primary-hover);
}
.btn-outline-primary {
    color: var(--bg-primary);
    border-color: var(--bg-primary);
}
.btn-outline-primary:hover {
    background: var(--bg-primary);
    border-color: var(--bg-primary);
}

/* ========== Form Controls ========== */
.form-control, .form-select {
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--border-color);
}
.form-control:focus, .form-select:focus {
    border-color: var(--bg-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}
.form-control::placeholder { color: var(--text-muted); }

/* ========== Alerts ========== */
.alert { border-radius: var(--radius); }

/* ========== Table ========== */
.table { color: var(--text-primary); }
.table-hover > tbody > tr:hover { background: var(--bg-code); }

/* ========== Badge ========== */
.badge { font-weight: 500; }

/* ========== Dropdown ========== */
.dropdown-menu {
    background: var(--bg-card);
    border-color: var(--border-color);
}
.dropdown-item { color: var(--text-primary); }
.dropdown-item:hover { background: var(--bg-code); }

/* ========== Scrollbar ========== */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-body); }
::-webkit-scrollbar-thumb { background: var(--text-muted); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }

/* ========== Responsive ========== */
@media (max-width: 768px) {
    .article-thumb { display: none; }
    .search-form { max-width: 100%; margin: 0.5rem 0; }
    .article-title { font-size: 1.4rem; }
    .featured-img { max-height: 180px; }
    .nav-btn { margin: 0.25rem; }
}