:root {
    --bg: #0f1320;
    --bg-soft: #171c2e;
    --panel: #1e2438;
    --panel-2: #252c45;
    --border: #313a5c;
    --text: #e6e9f5;
    --muted: #9aa3c4;
    --accent: #8b7dff;
    --accent-2: #61dafb;
    --green: #4ade80;
    --red: #fb7185;
    --code-font: "JetBrains Mono", "Fira Code", "SF Mono", Consolas, monospace;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.layout { display: flex; min-height: 100vh; }

/* ───────── Sidebar ───────── */
.sidebar {
    width: 280px;
    flex-shrink: 0;
    background: var(--bg-soft);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    position: sticky;
    top: 0;
    height: 100vh;
    overflow-y: auto;
}
.brand {
    display: flex; align-items: center; gap: 12px;
    padding: 22px 20px;
    border-bottom: 1px solid var(--border);
}
.brand .logo { font-size: 32px; }
.brand strong { display: block; font-size: 16px; }
.brand small { color: var(--muted); font-size: 12px; }

nav { padding: 12px 10px; flex: 1; }
.nav-item {
    display: flex; align-items: center; gap: 12px;
    padding: 11px 14px;
    border-radius: 10px;
    color: var(--muted);
    text-decoration: none;
    font-size: 14px;
    margin-bottom: 2px;
    transition: background .15s, color .15s;
}
.nav-item:hover { background: var(--panel); color: var(--text); }
.nav-item.active {
    background: linear-gradient(90deg, rgba(139,125,255,.22), rgba(139,125,255,.05));
    color: #fff;
    box-shadow: inset 2px 0 0 var(--accent);
}
.nav-icon { font-size: 18px; width: 22px; text-align: center; }
.sidebar-foot {
    padding: 16px 20px;
    border-top: 1px solid var(--border);
    color: var(--muted);
    font-size: 12px;
}

/* ───────── Content ───────── */
.content {
    flex: 1;
    max-width: 920px;
    margin: 0 auto;
    padding: 40px 48px 80px;
    width: 100%;
}
.lesson-head h1 {
    font-size: 30px;
    margin: 0 0 8px;
    display: flex; align-items: center; gap: 12px;
}
.intro {
    color: var(--muted);
    font-size: 16px;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent);
    padding: 14px 18px;
    border-radius: 10px;
}

.textblock {
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 4px 22px;
    margin: 24px 0;
}
.textblock h4, .codeblock h4 {
    font-size: 16px;
    margin: 18px 0 6px;
    color: var(--accent-2);
}
.textblock ol { padding-left: 22px; }
.textblock li { margin: 4px 0; }

/* Inline-Code-Schnipsel innerhalb von Erklärungen */
.snippet {
    background: #0b0e16;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px 16px;
    margin: 10px 0;
    overflow-x: auto;
}
.snippet code {
    background: none;
    color: #cfe3d0;
    padding: 0;
    font-size: 13px;
    line-height: 1.55;
    white-space: pre;
}
.codeblock { margin: 34px 0; }
.codeblock h3 { font-size: 19px; margin-bottom: 6px; }
.explain { color: var(--muted); margin: 0 0 14px; }

code {
    font-family: var(--code-font);
    background: var(--panel-2);
    padding: 2px 6px;
    border-radius: 5px;
    font-size: .9em;
    color: var(--accent-2);
}

.task {
    background: rgba(74, 222, 128, .08);
    border: 1px solid rgba(74, 222, 128, .3);
    border-radius: 10px;
    padding: 12px 16px;
    margin-bottom: 14px;
    font-size: 14px;
}
.task-label { color: var(--green); font-weight: 600; margin-right: 8px; }

/* Ausklappbare Lösung */
.solution {
    margin-top: 12px;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
}
.solution summary {
    cursor: pointer;
    padding: 12px 16px;
    font-weight: 600;
    color: var(--accent-2);
    user-select: none;
    list-style: none;
}
.solution summary::-webkit-details-marker { display: none; }
.solution summary::before { content: "▸ "; }
.solution[open] summary::before { content: "▾ "; }
.solution summary:hover { background: var(--panel); }
.solution-hint { color: var(--muted); font-size: 13px; margin: 0 16px; }
.solution .snippet { margin: 8px 16px 16px; }

/* ───────── Editor ───────── */
.editor {
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
    background: var(--panel);
    box-shadow: 0 10px 30px rgba(0,0,0,.25);
}
.editor-bar {
    display: flex; align-items: center; gap: 12px;
    background: var(--panel-2);
    padding: 9px 14px;
    border-bottom: 1px solid var(--border);
}
.dots { display: flex; gap: 6px; }
.dots i { width: 11px; height: 11px; border-radius: 50%; background: #4b5575; display: block; }
.dots i:nth-child(1){ background:#fb7185; } .dots i:nth-child(2){ background:#fbbf24; } .dots i:nth-child(3){ background:#4ade80; }
.editor-title { color: var(--muted); font-size: 12px; font-family: var(--code-font); }
.editor-actions { margin-left: auto; display: flex; gap: 8px; }

.btn-run, .btn-reset {
    border: none;
    border-radius: 8px;
    padding: 7px 14px;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: filter .15s, opacity .15s;
}
.btn-run { background: var(--accent); color: #fff; }
.btn-run:hover { filter: brightness(1.12); }
.btn-run:disabled { opacity: .6; cursor: wait; }
.btn-reset { background: transparent; color: var(--muted); }
.btn-reset:hover { color: var(--text); }
.btn-check { background: var(--green); color: #08160c; }
.btn-check:hover { filter: brightness(1.1); }
.btn-check:disabled { opacity: .6; cursor: wait; }

.check-result {
    padding: 12px 16px;
    border-top: 1px solid var(--border);
    font-size: 14px;
    font-weight: 600;
}
.check-result.ok  { background: rgba(74, 222, 128, .12); color: var(--green); }
.check-result.bad { background: rgba(251, 113, 133, .12); color: var(--red); }
.check-result .got {
    display: block;
    margin-top: 6px;
    font-weight: 400;
    color: var(--muted);
    font-family: var(--code-font);
    font-size: 12.5px;
    white-space: pre-wrap;
}

.dice-bar {
    margin-top: 12px;
    font-size: 13px;
    color: var(--muted);
    background: var(--bg-soft);
    border: 1px dashed var(--border);
    border-radius: 8px;
    padding: 8px 14px;
}
.dice-bar a { color: var(--accent-2); text-decoration: none; font-weight: 600; }
.dice-bar a:hover { text-decoration: underline; }

/* ───────── Schreibtischtest ───────── */
.deskcheck {
    margin: 34px 0;
    padding: 22px;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: 14px;
}
.deskcheck h3 { font-size: 19px; margin: 0 0 8px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.badge {
    font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .04em;
    padding: 3px 9px; border-radius: 999px; background: var(--panel-2); color: var(--muted);
}
.badge.typ { background: rgba(139,125,255,.18); color: var(--accent); }
.badge.diff-einfach { background: rgba(74,222,128,.16); color: var(--green); }
.badge.diff-mittel  { background: rgba(251,191,36,.16); color: #fbbf24; }
.badge.diff-schwer  { background: rgba(251,113,133,.16); color: var(--red); }

.deskcode { margin: 12px 0; }
.startwerte { font-size: 14px; color: var(--muted); margin: 10px 0; }
.startwerte code { margin-right: 8px; }

.table-scroll { overflow-x: auto; margin: 14px 0; border-radius: 10px; }
.desk-table { border-collapse: collapse; width: 100%; min-width: 520px; }
.desk-table th, .desk-table td {
    border: 1px solid var(--border);
    padding: 8px 10px;
    text-align: left;
    font-size: 14px;
    vertical-align: middle;
}
.desk-table th {
    background: var(--panel-2);
    color: var(--text);
    font-family: var(--code-font);
    font-size: 12.5px;
    white-space: nowrap;
}
.desk-table td.fixed { color: var(--muted); font-family: var(--code-font); white-space: nowrap; background: rgba(255,255,255,.02); }
.desk-table tr.fixed-row td { background: rgba(139,125,255,.06); }

.desk-cell {
    width: 100%;
    min-width: 110px;
    box-sizing: border-box;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 7px;
    color: #f0f3ff;
    font-family: var(--code-font);
    font-size: 13.5px;
    padding: 7px 9px;
    outline: none;
}
.desk-cell:focus { border-color: var(--accent); }
.desk-cell.ok    { border-color: var(--green); background: rgba(74,222,128,.10); }
.desk-cell.bad   { border-color: var(--red);   background: rgba(251,113,133,.10); }
.desk-cell.shown { border-color: var(--accent-2); background: rgba(97,218,251,.08); }

.desk-actions { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 4px; }
.btn-solution { background: transparent; color: var(--accent-2); border: 1px solid var(--border); border-radius: 8px; padding: 7px 14px; font-size: 13px; font-weight: 600; cursor: pointer; }
.btn-solution:hover { border-color: var(--accent-2); }

.desk-feedback { margin-top: 14px; padding: 12px 16px; border-radius: 10px; font-size: 14px; font-weight: 600; }
.desk-feedback.ok    { background: rgba(74,222,128,.12); color: var(--green); }
.desk-feedback.bad   { background: rgba(251,113,133,.12); color: var(--red); }
.desk-feedback.shown { background: rgba(97,218,251,.10); color: var(--accent-2); }

.deskexpected { margin-top: 14px; }
.hinweis {
    margin-top: 14px;
    font-size: 13.5px;
    color: var(--muted);
    background: rgba(251,191,36,.07);
    border: 1px solid rgba(251,191,36,.25);
    border-radius: 10px;
    padding: 10px 14px;
}

.code-input {
    width: 100%;
    border: none;
    outline: none;
    resize: vertical;
    background: var(--panel);
    color: #f0f3ff;
    font-family: var(--code-font);
    font-size: 14px;
    line-height: 1.6;
    padding: 16px;
    min-height: 160px;
    tab-size: 4;
    display: block;
}

.output-wrap { border-top: 1px solid var(--border); }
.output-bar {
    display: flex; justify-content: space-between;
    background: #11151f;
    padding: 7px 14px;
    font-size: 12px;
    color: var(--muted);
}
.output-meta.error { color: var(--red); }
.output-meta.ok { color: var(--green); }
.output {
    margin: 0;
    padding: 16px;
    background: #0b0e16;
    color: #cfe3d0;
    font-family: var(--code-font);
    font-size: 13.5px;
    line-height: 1.55;
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 420px;
    overflow: auto;
}
.output.error { color: #ffd5da; }

/* ───────── Pager ───────── */
.pager {
    display: flex; justify-content: space-between; gap: 12px;
    margin-top: 50px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}
.pager-btn {
    color: var(--muted);
    text-decoration: none;
    padding: 12px 18px;
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 14px;
    transition: all .15s;
    max-width: 48%;
}
.pager-btn:hover { color: #fff; border-color: var(--accent); background: var(--panel); }
.pager-btn.next { margin-left: auto; }

/* ───────── Responsive ───────── */
@media (max-width: 820px) {
    .layout { flex-direction: column; }
    .sidebar { width: 100%; height: auto; position: relative; }
    nav { display: flex; flex-wrap: wrap; }
    .nav-item span:not(.nav-icon) { display: none; }
    .nav-item { padding: 10px 12px; }
    .content { padding: 24px 18px 60px; }
}