/* ==========================================================================
   Lernportal – Cyber-HUD-Theme
   Dunkles, futuristisches Design: Glas-Panels, Neon-Akzente, dezente
   Animationen. Alle Farben zentral als Variablen; JS-Views nutzen dieselben
   Variablen (--panel-2, --sel-bg, --ok-bg, --err-bg) statt Hex-Werten.
   ========================================================================== */

:root {
    --bg: #070b14;
    --bg-2: #0b1120;
    --panel: rgba(15, 23, 42, 0.72);
    --panel-2: rgba(23, 33, 56, 0.85);
    --text: #dbe4f3;
    --muted: #8b98ad;
    --primary: #38e1ff;          /* Neon-Cyan */
    --primary-dark: #19b8d6;
    --accent: #a78bfa;           /* Violett */
    --border: rgba(120, 150, 200, 0.22);
    --border-glow: rgba(56, 225, 255, 0.35);
    --success: #34d399;
    --warning: #fbbf24;
    --danger: #f87171;
    --sel-bg: rgba(56, 225, 255, 0.12);
    --ok-bg: rgba(52, 211, 153, 0.14);
    --err-bg: rgba(248, 113, 113, 0.14);
    --radius: 12px;
    --glow: 0 0 24px rgba(56, 225, 255, 0.18);
    --font-head: "Segoe UI", system-ui, sans-serif;
    --font-mono: Consolas, "Cascadia Mono", monospace;
}

* { box-sizing: border-box; }

html { scrollbar-color: #24344f var(--bg); }

body {
    margin: 0;
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

/* --- HUD-Hintergrund: Gitternetz + Farbnebel ------------------------------ */
body::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: -2;
    background:
        radial-gradient(60rem 40rem at 85% -10%, rgba(56, 225, 255, 0.10), transparent 60%),
        radial-gradient(50rem 35rem at -10% 110%, rgba(167, 139, 250, 0.10), transparent 60%),
        linear-gradient(180deg, var(--bg-2), var(--bg) 40%);
}
body::after {
    content: "";
    position: fixed;
    inset: 0;
    z-index: -1;
    background-image:
        linear-gradient(rgba(120, 150, 200, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(120, 150, 200, 0.05) 1px, transparent 1px);
    background-size: 42px 42px;
    mask-image: radial-gradient(ellipse 90% 70% at 50% 0%, black 30%, transparent 100%);
    pointer-events: none;
}

/* --- Topbar --------------------------------------------------------------- */
.topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    background: rgba(7, 11, 20, 0.75);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 1px 0 rgba(56, 225, 255, 0.12);
    padding: 0.7rem 1.5rem;
}

.topbar .brand {
    font-family: var(--font-head);
    font-weight: 800;
    font-size: 1.05rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    text-decoration: none;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}
.topbar .brand::before {
    content: "▮";
    margin-right: 0.5rem;
    color: var(--primary);
    -webkit-text-fill-color: var(--primary);
    animation: pulse 2.4s ease-in-out infinite;
}

.topbar nav a {
    position: relative;
    margin: 0 0.75rem;
    padding: 0.3rem 0.1rem;
    color: var(--text);
    text-decoration: none;
    font-size: 0.95rem;
    letter-spacing: 0.03em;
    transition: color 0.2s ease;
}
.topbar nav a::after {
    content: "";
    position: absolute;
    left: 0; right: 100%; bottom: -2px;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transition: right 0.25s ease;
}
.topbar nav a:hover { color: var(--primary); }
.topbar nav a:hover::after { right: 0; }

.user-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--muted);
    font-size: 0.88rem;
}

.link-button {
    background: none;
    border: 1px solid var(--border);
    border-radius: 999px;
    color: var(--primary);
    cursor: pointer;
    font: inherit;
    font-size: 0.85rem;
    padding: 0.25rem 0.9rem;
    text-decoration: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.link-button:hover { border-color: var(--border-glow); box-shadow: var(--glow); }

/* --- Layout & Typografie -------------------------------------------------- */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 2.25rem 1.5rem 4rem;
}

h1, h2, h3 { font-family: var(--font-head); color: #f1f6ff; line-height: 1.25; }
h1 {
    font-size: 1.9rem;
    letter-spacing: 0.02em;
    background: linear-gradient(90deg, #f1f6ff 30%, var(--primary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}
h2 { font-size: 1.35rem; }
h3 { font-size: 1.08rem; letter-spacing: 0.02em; }

.subtitle { color: var(--muted); margin-top: -0.5rem; }

a { color: var(--primary); }

/* --- Karten (Glas-Panels) -------------------------------------------------- */
.card {
    position: relative;
    background: var(--panel);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.4rem;
    animation: rise 0.45s ease both;
    transition: border-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
}
.card::before {
    content: "";
    position: absolute;
    top: 0; left: 1rem; right: 1rem;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--border-glow), transparent);
}
.card:hover { border-color: rgba(120, 150, 200, 0.4); box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35); }

.card a.card-link { display: block; text-decoration: none; color: inherit; }

/* --- Themenblock-Listen ----------------------------------------------------- */
.themenblock-list, .aufgabe-list { list-style: none; padding: 0; }

.themenblock-list li {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 0.7rem;
    background: var(--panel-2);
    overflow: hidden;
    transition: border-color 0.22s ease, box-shadow 0.22s ease, transform 0.22s ease;
}
.themenblock-list li:hover {
    border-color: var(--border-glow);
    box-shadow: var(--glow);
    transform: translateX(4px);
}

.themenblock-list li a {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.75rem;
    padding: 0.95rem 1.2rem;
    text-decoration: none;
    color: var(--text);
}
.themenblock-list li a::before {
    content: "›";
    color: var(--primary);
    font-weight: 700;
    margin-right: 0.35rem;
}
.themenblock-list li a:hover { color: var(--primary); }

.badge {
    display: inline-block;
    padding: 0.18rem 0.7rem;
    border-radius: 999px;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    background: var(--sel-bg);
    border: 1px solid var(--border-glow);
    color: var(--primary);
    white-space: nowrap;
}

/* --- Formulare -------------------------------------------------------------- */
form.stacked label {
    display: block;
    font-weight: 600;
    margin: 1rem 0 0.3rem;
    color: #eef3fc;
    letter-spacing: 0.02em;
}

form.stacked input[type=text],
form.stacked input[type=email],
form.stacked input[type=password],
form.stacked textarea,
form.stacked select,
.answer-input {
    width: 100%;
    padding: 0.65rem 0.85rem;
    background: rgba(7, 11, 20, 0.6);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text);
    font: inherit;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
form.stacked input:focus, form.stacked textarea:focus,
form.stacked select:focus, .answer-input:focus {
    outline: none;
    border-color: var(--border-glow);
    box-shadow: var(--glow);
}
form.stacked select option { background: var(--bg-2); }

form.stacked textarea { min-height: 5rem; resize: vertical; }

/* --- Buttons ----------------------------------------------------------------- */
button.primary, a.primary-btn {
    display: inline-block;
    background: linear-gradient(115deg, var(--primary-dark), var(--primary) 55%, var(--accent));
    background-size: 160% 100%;
    color: #04121c;
    border: none;
    padding: 0.68rem 1.5rem;
    border-radius: 999px;
    font: inherit;
    font-weight: 700;
    letter-spacing: 0.03em;
    cursor: pointer;
    text-decoration: none;
    margin-top: 1rem;
    transition: background-position 0.3s ease, box-shadow 0.3s ease, transform 0.15s ease;
}
button.primary:hover, a.primary-btn:hover {
    background-position: 90% 0;
    box-shadow: 0 0 26px rgba(56, 225, 255, 0.35);
    transform: translateY(-1px);
}
button.primary:active, a.primary-btn:active { transform: translateY(0); }

button.secondary {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.62rem 1.3rem;
    border-radius: 999px;
    font: inherit;
    cursor: pointer;
    margin-top: 1rem;
    margin-left: 0.5rem;
    transition: border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}
button.secondary:hover { border-color: var(--border-glow); color: var(--primary); box-shadow: var(--glow); }

button:disabled { opacity: 0.75; cursor: default; }

/* --- Fehler & Feedback -------------------------------------------------------- */
.error-box {
    background: var(--err-bg);
    border: 1px solid rgba(248, 113, 113, 0.4);
    color: var(--danger);
    padding: 0.75rem 1rem;
    border-radius: var(--radius);
    margin-bottom: 1rem;
}

.feedback-correct { color: var(--success); font-weight: 700; text-shadow: 0 0 14px rgba(52, 211, 153, 0.35); }
.feedback-partial { color: var(--warning); font-weight: 700; }
.feedback-incorrect { color: var(--danger); font-weight: 700; }

/* --- Inhaltsblöcke (Zusammenfassung) ------------------------------------------ */
.content-block { margin-bottom: 1.25rem; }

.content-block.definition_box, .content-block.example_box {
    background: var(--panel-2);
    border: 1px solid var(--border);
    border-left: 3px solid var(--primary);
    padding: 1rem 1.2rem;
    border-radius: 0 var(--radius) var(--radius) 0;
    box-shadow: inset 0 0 30px rgba(56, 225, 255, 0.04);
}
.content-block.example_box { border-left-color: var(--accent); }

.content-block.definition_box .caption, .content-block.example_box .caption {
    font-weight: 700;
    display: block;
    margin-bottom: 0.35rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    font-size: 0.82rem;
    color: var(--primary);
}
.content-block.example_box .caption { color: var(--accent); }

.content-block.situation { font-style: italic; color: var(--muted); }
.content-block.leitfrage {
    font-weight: 700;
    font-size: 1.08rem;
    color: #f1f6ff;
    padding-left: 0.9rem;
    border-left: 3px solid var(--accent);
}
.content-block.lernziel::before { content: "▸ "; color: var(--primary); }

/* --- Karteikarten --------------------------------------------------------------- */
.flashcard {
    position: relative;
    background: linear-gradient(160deg, rgba(23, 33, 56, 0.9), rgba(13, 19, 34, 0.9));
    border: 1px solid var(--border);
    border-radius: var(--radius);
    min-height: 12rem;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 2rem;
    font-size: 1.18rem;
    cursor: pointer;
    margin-bottom: 1rem;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}
.flashcard:hover {
    transform: perspective(900px) rotateX(2deg) translateY(-3px);
    border-color: var(--border-glow);
    box-shadow: var(--glow);
}
.flashcard .hint {
    display: block;
    margin-top: 1rem;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--muted);
}

/* --- Prüfung ---------------------------------------------------------------------- */
.timer {
    font-family: var(--font-mono);
    font-variant-numeric: tabular-nums;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--primary);
    text-shadow: 0 0 16px rgba(56, 225, 255, 0.45);
}

.progress-list { list-style: none; padding: 0; }
.progress-list li { padding: 0.55rem 0; border-bottom: 1px solid var(--border); }

/* --- MC-Optionen (Lernmodus, JS-generiert) ------------------------------------------ */
.mc-option { transition: border-color 0.15s ease, background 0.15s ease, box-shadow 0.15s ease; }
.mc-option:hover:not(:disabled) { border-color: var(--border-glow) !important; box-shadow: var(--glow); }

/* --- Diagramme (Inline-SVG) ----------------------------------------------------------- */
.diagram {
    margin: 1rem 0;
    padding: 0.8rem 1rem;
    background: rgba(7, 11, 20, 0.55);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    max-width: 340px;
    color: #cfe6ff; /* SVGs zeichnen mit currentColor */
}
.diagram svg { display: block; max-width: 100%; height: auto; }
.diagram figcaption {
    margin-top: 0.5rem;
    font-size: 0.78rem;
    color: var(--muted);
    text-align: center;
    line-height: 1.35;
}

/* --- Animationen ------------------------------------------------------------------------ */
@keyframes rise {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
}
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50%      { opacity: 0.35; }
}

/* Gestaffeltes Einblenden der ersten Karten */
.card:nth-of-type(2) { animation-delay: 0.06s; }
.card:nth-of-type(3) { animation-delay: 0.12s; }
.card:nth-of-type(4) { animation-delay: 0.18s; }

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* --- Scrollbar (WebKit) ------------------------------------------------------------------- */
::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: #24344f; border-radius: 999px; }
::-webkit-scrollbar-thumb:hover { background: #2f4568; }