:root {
    --bg: #0f172a;
    --surface: #1e293b;
    --surface-alt: #273549;
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --accent: #22c55e;
    --accent-dark: #16a34a;
    --danger: #ef4444;
    --border: #334155;
    --radius: 10px;
}

* {
    box-sizing: border-box;
}

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

.container {
    max-width: 640px;
    margin: 0 auto;
    padding: 1rem;
}

.header-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

h1 {
    font-size: 1.4rem;
    margin: 0;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1rem;
    margin-bottom: 1rem;
}

.flex {
    display: flex;
}

.flex-col {
    display: flex;
    flex-direction: column;
}

.gap-2 {
    gap: 0.5rem;
}

.items-center {
    align-items: center;
}

.mb-1 {
    margin-bottom: 1rem;
}

input {
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text);
    padding: 0.6rem 0.8rem;
    font-size: 1rem;
    width: 100%;
}

button {
    border: none;
    border-radius: var(--radius);
    padding: 0.6rem 1rem;
    font-size: 1rem;
    cursor: pointer;
}

.save-btn {
    background: var(--accent);
    color: #052e13;
    font-weight: 600;
}

.save-btn:hover {
    background: var(--accent-dark);
}

.save-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.nav-btn {
    background: var(--surface-alt);
    color: var(--text);
}

.nav-btn.active {
    background: var(--accent);
    color: #052e13;
    font-weight: 600;
}

.nav-tabs {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.logout-btn,
.delete-btn {
    background: transparent;
    color: var(--danger);
    border: 1px solid var(--danger);
}

.hint-text {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.error-msg {
    color: var(--danger);
    font-size: 0.9rem;
}

.status-msg.success {
    color: var(--accent);
    font-size: 0.9rem;
}

.auth-switch {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.auth-switch a {
    color: var(--accent);
}

.welcome {
    text-align: center;
    padding: 2rem 0;
}

.deck-form,
.card-form {
    margin-bottom: 1rem;
}

.deck-list,
.card-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.deck-row,
.card-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
    background: var(--surface-alt);
    border-radius: var(--radius);
    padding: 0.6rem 0.8rem;
}

.deck-row-main {
    flex: 1;
    cursor: pointer;
}

.preset-list {
    margin-bottom: 1.5rem;
}

.preset-list h3 {
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
}

.preset-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
    background: var(--surface-alt);
    border-radius: var(--radius);
    padding: 0.6rem 0.8rem;
    margin-bottom: 0.5rem;
}

.study-view {
    text-align: center;
}

.flashcard {
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.5rem 1rem;
    margin: 1rem 0;
    cursor: pointer;
    min-height: 120px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 0.5rem;
}

.flashcard-front {
    font-size: 1.6rem;
    font-weight: 600;
    margin: 0;
}

.flashcard-back {
    font-size: 1.3rem;
    color: var(--accent);
    margin: 0;
}

.study-actions {
    justify-content: center;
}

.review-btn {
    flex: 1;
    max-width: 200px;
    font-weight: 600;
}

.review-btn.correct {
    background: var(--accent);
    color: #052e13;
}

.review-btn.wrong {
    background: var(--danger);
    color: #fff;
}

/* Mobile: größere Tap-Targets, gestapelte Formulare */
@media (max-width: 480px) {
    .container {
        padding: 0.75rem;
    }

    h1 {
        font-size: 1.2rem;
    }

    .card-form,
    .deck-form .flex {
        flex-direction: column;
    }

    .flashcard {
        padding: 2rem 0.75rem;
        min-height: 160px;
    }

    .flashcard-front {
        font-size: 1.4rem;
    }

    button {
        padding: 0.75rem 1rem;
    }
}

.app-footer {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-muted);
}

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

.impressum-view h3 {
    font-size: 0.95rem;
    margin-bottom: 0.2rem;
}

.impressum-view p {
    margin-top: 0;
    margin-bottom: 1rem;
    color: var(--text-muted);
}

.secondary-btn {
    background: var(--surface-alt);
    color: var(--text);
    border: 1px solid var(--border);
}