/* ----- PRO THEME: dark & light variables ----- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    padding: 2rem 1rem;
    transition: background 0.25s ease, color 0.2s;
}

/* light / dark base (default dark) */
body.light {
    background: #f6f8fa;
    color: #24292f;
}
body.dark {
    background: #0d1117;
    color: #e6edf3;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    border-radius: 32px;
    padding: 2rem 2.5rem;
    box-shadow: 0 25px 50px -12px rgba(0,0,0,0.6);
    transition: background 0.25s, border 0.2s;
}
body.dark .container {
    background: #161b22;
    border: 1px solid #30363d;
}
body.light .container {
    background: #ffffff;
    border: 1px solid #d0d7de;
}

/* two-column layout */
.two-col {
    display: flex;
    gap: 2.5rem;
    align-items: flex-start;
}

.left-col {
    flex: 0 0 280px;
    position: sticky;
    top: 1.5rem;
    align-self: flex-start;
    max-height: calc(100vh - 3rem);
    overflow-y: auto;
    padding-right: 0.5rem;
}

.right-col {
    flex: 1;
    min-width: 0;
}

/* left-col scroll styling */
.left-col::-webkit-scrollbar {
    width: 4px;
}
.left-col::-webkit-scrollbar-track {
    background: transparent;
}
.left-col::-webkit-scrollbar-thumb {
    background: #30363d;
    border-radius: 20px;
}
body.light .left-col::-webkit-scrollbar-thumb {
    background: #c0c8d4;
}

/* header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    padding-bottom: 1.5rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid;
    transition: border-color 0.2s;
}
body.dark .header { border-color: #30363d; }
body.light .header { border-color: #d0d7de; }

.header h1 {
    font-weight: 600;
    font-size: 2.2rem;
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 10px;
}
body.dark .header h1 {
    background: linear-gradient(135deg, #f0e6d0, #58a6ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
body.light .header h1 {
    background: linear-gradient(135deg, #1f2937, #2563eb);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.header h1 i { -webkit-text-fill-color: #58a6ff; margin-right: 4px; }

.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.theme-toggle {
    background: transparent;
    border: 1px solid;
    border-radius: 40px;
    padding: 0.45rem 1.2rem;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: 0.2s;
    color: inherit;
}
body.dark .theme-toggle {
    border-color: #30363d;
    background: #21262d;
}
body.light .theme-toggle {
    border-color: #d0d7de;
    background: #f0f2f5;
}
.theme-toggle:hover {
    opacity: 0.8;
    transform: scale(0.97);
}

.badge {
    padding: 0.4rem 1.2rem;
    border-radius: 40px;
    font-size: 0.85rem;
    border: 1px solid;
    transition: 0.2s;
}
body.dark .badge {
    background: #21262d;
    border-color: #30363d;
    color: #8b949e;
}
body.light .badge {
    background: #f0f2f5;
    border-color: #d0d7de;
    color: #57606a;
}

/* TOC */
.toc {
    border-radius: 20px;
    padding: 1.5rem 1.8rem;
    margin-bottom: 1.5rem;
    border: 1px solid;
    transition: 0.2s;
}
body.dark .toc { background: #0d1117; border-color: #30363d; }
body.light .toc { background: #f6f8fa; border-color: #d0d7de; }

.toc h2 {
    font-size: 1.1rem;
    font-weight: 500;
    letter-spacing: 0.3px;
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 10px;
    color: #8b949e;
}
body.light .toc h2 { color: #57606a; }

.toc-grid {
    display: flex;
    flex-direction: column;
    gap: 0.25rem 0;
}
.toc-grid a {
    text-decoration: none;
    font-size: 0.9rem;
    transition: 0.2s;
    border-bottom: 1px solid transparent;
    font-weight: 450;
    padding: 0.2rem 0.4rem;
    border-radius: 6px;
}
body.dark .toc-grid a { color: #58a6ff; }
body.light .toc-grid a { color: #2563eb; }
.toc-grid a:hover {
    background: rgba(88, 166, 255, 0.1);
    border-bottom-color: #58a6ff;
    padding-left: 0.8rem;
}
body.light .toc-grid a:hover { background: rgba(37, 99, 235, 0.08); }

/* sidebar extra card */
.sidebar-card {
    border-radius: 20px;
    padding: 1.5rem 1.8rem;
    border: 1px solid;
    transition: 0.2s;
}
body.dark .sidebar-card { background: #0d1117; border-color: #30363d; }
body.light .sidebar-card { background: #f6f8fa; border-color: #d0d7de; }

.sidebar-card-icon {
    font-size: 2rem;
    color: #58a6ff;
    margin-bottom: 0.5rem;
}
.sidebar-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}
body.dark .sidebar-card h3 { color: #f0e6d0; }
body.light .sidebar-card h3 { color: #1f2937; }
.sidebar-card p {
    font-size: 0.9rem;
    opacity: 0.8;
    margin-bottom: 0.75rem;
}
.sidebar-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}
.sidebar-tags span {
    font-size: 0.7rem;
    font-weight: 500;
    padding: 0.15rem 0.7rem;
    border-radius: 20px;
    background: #21262d;
    border: 1px solid #30363d;
    color: #8b949e;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}
body.light .sidebar-tags span {
    background: #e9ecf0;
    border-color: #d0d7de;
    color: #57606a;
}

/* sections */
.section {
    margin-bottom: 3rem;
    scroll-margin-top: 1rem;
}
.section-title {
    font-size: 1.8rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    padding-bottom: 0.5rem;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid;
    display: flex;
    align-items: center;
    gap: 12px;
    transition: border-color 0.2s;
}
body.dark .section-title { border-color: #30363d; color: #f0e6d0; }
body.light .section-title { border-color: #d0d7de; color: #1f2937; }
.section-title i { color: #58a6ff; font-size: 1.6rem; }

.card {
    border-radius: 20px;
    padding: 1.5rem 1.8rem;
    margin-bottom: 1.5rem;
    border: 1px solid;
    transition: border 0.2s, background 0.2s;
}
body.dark .card { background: #0d1117; border-color: #21262d; }
body.light .card { background: #ffffff; border-color: #d0d7de; }
.card:hover { border-color: #58a6ff; }

.card h3 {
    font-weight: 500;
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 8px;
}
body.dark .card h3 { color: #f0e6d0; }
body.light .card h3 { color: #1f2937; }
.card h3 i { color: #58a6ff; width: 1.4rem; }

.code-block {
    border-radius: 14px;
    padding: 1.2rem 1.5rem;
    margin: 1rem 0;
    border-left: 4px solid #58a6ff;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    font-size: 0.9rem;
    overflow-x: auto;
    white-space: pre-wrap;
    word-break: break-word;
    transition: background 0.2s, border 0.2s;
}
body.dark .code-block {
    background: #0a0e14;
    border: 1px solid #21262d;
    border-left-width: 4px;
    color: #e6edf3;
}
body.light .code-block {
    background: #f6f8fa;
    border: 1px solid #d0d7de;
    border-left-width: 4px;
    color: #24292f;
}
.inline-code {
    padding: 0.2rem 0.6rem;
    border-radius: 8px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    color: #f0883e;
    transition: background 0.2s;
}
body.dark .inline-code { background: #21262d; }
body.light .inline-code { background: #e9ecf0; }

ul, ol { padding-left: 1.5rem; margin: 0.8rem 0; }
li { margin-bottom: 0.3rem; }

.grid-2 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 0.5rem;
}

hr {
    border: 0;
    height: 1px;
    margin: 2rem 0;
    transition: background 0.2s;
}
body.dark hr { background: #30363d; }
body.light hr { background: #d0d7de; }

/* footer */
.footer {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    transition: border-color 0.2s;
}
body.dark .footer { border-color: #30363d; }
body.light .footer { border-color: #d0d7de; }

.footer a {
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 0.6rem 1.6rem;
    border-radius: 40px;
    border: 1px solid;
    transition: 0.2s;
}
body.dark .footer a {
    color: #58a6ff;
    background: #21262d;
    border-color: #30363d;
}
body.light .footer a {
    color: #2563eb;
    background: #f0f2f5;
    border-color: #d0d7de;
}
.footer a:hover {
    background: #30363d;
    color: #f0e6d0;
    border-color: #58a6ff;
}
body.light .footer a:hover { background: #d0d7de; color: #1f2937; }

.footer .credit {
    font-size: 0.9rem;
}
body.dark .footer .credit { color: #8b949e; }
body.light .footer .credit { color: #57606a; }

/* responsive */
@media (max-width: 1024px) {
    .two-col {
        flex-direction: column;
    }
    .left-col {
        flex: 1 1 auto;
        position: static;
        max-height: none;
        width: 100%;
        overflow-y: visible;
        padding-right: 0;
    }
    .toc-grid {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 0.3rem 1rem;
    }
}

@media (max-width: 768px) {
    body { padding: 1rem 0.5rem; }
    .container { padding: 1.2rem; }
    .header h1 { font-size: 1.6rem; }
    .section-title { font-size: 1.4rem; }
    .card { padding: 1rem; }
    .code-block { font-size: 0.8rem; padding: 0.8rem; }
    .footer { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 480px) {
    .header { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
    .badge { font-size: 0.7rem; padding: 0.3rem 0.8rem; }
    .theme-toggle { font-size: 0.75rem; padding: 0.3rem 0.8rem; }
}

::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: #0d1117; }
::-webkit-scrollbar-thumb { background: #30363d; border-radius: 20px; }
::-webkit-scrollbar-thumb:hover { background: #58a6ff; }
body.light ::-webkit-scrollbar-track { background: #f0f2f5; }
body.light ::-webkit-scrollbar-thumb { background: #c0c8d4; }