*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    min-height: 100vh;
    line-height: 1.5;
}

.app {
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr;
    grid-template-rows: 1fr var(--log-height);
    min-height: 100vh;
}

.sidebar {
    grid-row: 1 / 3;
    background: var(--color-surface);
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar-header {
    padding: 1.25rem 1.25rem 1rem;
    border-bottom: 1px solid var(--color-border);
}

.sidebar-header h1 {
    margin: 0 0 0.25rem;
    font-size: 1.125rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.sidebar-header p {
    margin: 0;
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    flex: 1;
    min-height: 0;
    overflow-y: auto;
}

.lesson-nav {
    list-style: none;
    margin: 0;
    padding: 0.75rem 0;
    flex-shrink: 0;
}

.lesson-nav a {
    display: block;
    padding: 0.5rem 1.25rem;
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    border-left: 3px solid transparent;
    transition:
        color 0.15s,
        background 0.15s,
        border-color 0.15s;
}

.lesson-nav a:hover {
    color: var(--color-text);
    background: var(--color-surface-raised);
}

.lesson-nav a.active {
    color: var(--color-accent);
    background: var(--color-accent-muted);
    border-left-color: var(--color-accent);
    font-weight: 500;
}

.sidebar-footer {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.sidebar-footer a {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    text-decoration: none;
}

.sidebar-footer a:hover {
    color: var(--color-accent);
}

.plugin-section {
    border-top: 1px solid var(--color-border);
    margin-top: 0.25rem;
}

.plugin-section-title,
.plugin-group-title {
    padding: 0.625rem 1.25rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-text-muted);
    cursor: pointer;
    list-style: none;
}

.plugin-section-title::-webkit-details-marker,
.plugin-group-title::-webkit-details-marker {
    display: none;
}

.plugin-group {
    border-top: 1px solid var(--color-border-subtle);
}

.plugin-group-title {
    padding-left: 1.75rem;
    font-size: 0.8125rem;
    font-weight: 500;
    text-transform: none;
    letter-spacing: normal;
}

.plugin-lesson-nav {
    padding-top: 0;
    padding-bottom: 0.5rem;
}

.plugin-lesson-nav a {
    padding-left: 2rem;
    font-size: 0.8125rem;
}

.main {
    display: grid;
    grid-template-columns: minmax(280px, 1fr) minmax(380px, 1fr);
    grid-template-rows: minmax(0, 1fr);
    overflow: hidden;
    min-height: 0;
}

.canvas-column {
    display: flex;
    flex-direction: column;
    padding: 1rem;
    gap: 0.75rem;
    overflow: hidden;
    min-width: 0;
    min-height: 0;
}

.canvas-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-shrink: 0;
}

.canvas-header h2 {
    margin: 0;
    font-size: 1rem;
    font-weight: 600;
}

.canvas-host {
    flex: 1;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    display: flex;
    align-items: stretch;
    justify-content: stretch;
    padding: 0.5rem;
    overflow: hidden;
    box-shadow: var(--shadow-panel);
    min-height: 220px;
}

.canvas-host svg {
    flex: 1;
    width: 100%;
    height: 100%;
    min-height: 0;
    display: block;
}

.lesson-column {
    border-left: 1px solid var(--color-border);
    background: var(--color-surface);
    overflow-y: auto;
    padding: 1.25rem 1.5rem;
}

.lesson-title {
    margin: 0 0 0.5rem;
    font-size: 1.125rem;
    font-weight: 600;
}

.lesson-description {
    margin: 0 0 1rem;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.api-refs {
    display: flex;
    flex-wrap: wrap;
    gap: 0.375rem;
    margin-bottom: 1rem;
}

.controls {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.log-panel {
    grid-column: 2;
    border-top: 1px solid var(--color-border);
    background: var(--color-log-bg);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.log-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.5rem 1rem;
    border-bottom: 1px solid var(--color-border-subtle);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-muted);
}

.log-output {
    flex: 1;
    margin: 0;
    padding: 0.75rem 1rem;
    overflow-y: auto;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    line-height: 1.6;
    color: #cbd5e1;
}

.log-line {
    margin: 0 0 0.25rem;
    white-space: pre-wrap;
    word-break: break-word;
}

.log-line .time {
    color: #64748b;
}

.log-line .msg {
    color: #e2e8f0;
}

.log-line .detail {
    color: var(--color-success);
}

@media (max-width: 960px) {
    .app {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr auto var(--log-height);
    }

    .sidebar {
        grid-row: 1;
    }

    .main {
        grid-column: 1;
        grid-template-columns: 1fr;
    }

    .lesson-column {
        border-left: none;
        border-top: 1px solid var(--color-border);
    }

    .log-panel {
        grid-column: 1;
    }
}