:root {
    --bg-page: #f5f7fb;
    --bg-surface: #ffffff;
    --bg-surface-elevated: #f0f0f0;
    --bg-input: #ffffff;
    --text-main: #1a1a1a;
    --text-muted: #666666;
    --text-heading: #222222;
    --text-input: #1a1a1a;
    --text-latin: #007bff;
    --border-color: #dfe5ee;
    --border-subtle: #f0f0f0;
    --border-strong: #cccccc;
    --accent-blue: #3f7fff;
    --accent-blue-hover: #2f69df;
    --color-neu: #3f7fff;
    --color-6: #d23636;
    --color-5: #f08f8f;
    --color-4: #cc6310;
    --color-3: #d8b22f;
    --color-2: #74cf8f;
    --color-1: #1f8f49;
    --srs-track-bg: #e0e0e0;
    --warning-bg: #f8d7da;
    --warning-text: #842029;
}

[data-theme="dark"] {
    --bg-page: #000000;
    --bg-surface: #1a1a1a;
    --bg-surface-elevated: #222222;
    --bg-input: #0f0f0f;
    --text-main: #ffffff;
    --text-muted: #888888;
    --text-heading: #ffffff;
    --text-input: #ffffff;
    --text-latin: #9ac1ff;
    --border-color: #272727;
    --border-subtle: #2d2d2d;
    --border-strong: #2f2f2f;
    --accent-blue: #3f7fff;
    --accent-blue-hover: #2f69df;
    --srs-track-bg: #111111;
    --warning-bg: rgba(220, 53, 69, 0.15);
    --warning-text: #ffb3b8;
}

.theme-toggle-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    transition: background 0.2s, border-color 0.2s;
}
.theme-toggle-btn:hover {
    background: var(--bg-surface-elevated);
}

/* --- UNIVERSAL & LAYOUT --- */
* { margin: 0; padding: 0; box-sizing: border-box; }
body, html { height: 100%; width: 100%; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif; overflow: hidden; background: var(--bg-page); color: var(--text-main); }

/* 50/50 Hub Background */
.bg-layer { position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; display: grid; grid-template-columns: 1fr 1fr; z-index: 1; }
.side { display: flex; align-items: center; justify-content: center; cursor: pointer; transition: filter 0.2s ease; border: none; outline: none; }
.grammar { background-color: #2c3e50; }
.cards { background-color: #34495e; }
.side h2 { font-size: clamp(1.9rem, 2.7vw, 2.7rem); color: rgba(255, 255, 255, 0.2); text-transform: uppercase; letter-spacing: 2.5px; }
.side:hover { filter: brightness(1.2); }
.side:hover h2 { color: white; }

/* Dictionary (The Hovering Command Center) */
.dict-wrapper { position: fixed; top: 0; left: 0; width: 100%; height: 100%; display: flex; align-items: center; justify-content: center; z-index: 10; pointer-events: none; }
.container { 
    background: var(--bg-surface); padding: clamp(1.4rem, 3vw, 2.2rem); border-radius: 20px;
    box-shadow: 0 16px 36px rgba(11, 33, 66, 0.16); width: 92%; max-width: 560px;
    text-align: center; pointer-events: auto; 
}
h1 { margin-bottom: 6px; color: var(--text-heading); font-size: clamp(1.4rem, 2.2vw, 1.9rem); font-weight: 650; letter-spacing: -0.01em; }
#status { font-size: 0.75rem; color: var(--text-muted); margin-bottom: 20px; }
input { padding: 13px 15px; color: var(--text-input); background: var(--bg-input); width: 100%; border: 1px solid var(--border-color); border-radius: 12px; font-size: 17px; outline: none; transition: border-color 0.2s ease, box-shadow 0.2s ease; }
input:focus { border-color: var(--accent-blue); box-shadow: 0 0 0 4px rgba(0,123,255,0.1); }

/* Dictionary Results (RESTORED) */
#result { max-height: 250px; overflow-y: auto; margin-top: 15px; text-align: left; }
.result-item { padding: 12px; border-bottom: 1px solid #f9f9f9; display: block; line-height: 1.4; }
.latin-display { color: var(--text-latin) !important; font-weight: bold !important; font-size: 1.1rem; }
.german-text { color: var(--text-main) !important; font-weight: normal; margin-left: 5px; }
.match-score { float: right; font-size: 0.7rem; color: var(--text-muted); }

/* --- FLASHCARD MODE --- */
.flashcard-mode {
    background-color: var(--bg-page);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    height: 100vh;
    overflow: hidden;
    font-family: Inter, Roboto, -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
}

.kk-shell {
    width: min(1200px, 100vw);
    height: 100vh;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.kk-top-nav {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    grid-template-areas: "left title right";
    align-items: center;
    background: var(--bg-surface);
    border-radius: 10px;
    padding: 12px 16px;
}

.kk-nav-left { justify-self: start; }
.kk-nav-title {
    color: var(--text-main);
    font-size: 1.15rem;
    font-weight: 600;
    text-align: center;
    margin: 0;
}
.kk-menu-btn {
    justify-self: end;
    border: 1px solid var(--border-strong);
    background: var(--bg-surface-elevated);
    color: var(--text-main);
    padding: 8px 12px;
    border-radius: 10px;
    cursor: pointer;
}
.back-btn {
    border: 1px solid var(--border-strong);
    background: var(--bg-surface-elevated);
    color: var(--text-main);
    border-radius: 10px;
    padding: 8px 14px;
    cursor: pointer;
}

.kk-view {
    min-height: 0;
    flex: 1;
}

#menu-view {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    overflow-y: auto;
}

.deck-overview,
.dashboard-card,
.chapter-btn,
.deck-gallery-card,
.card-face,
.merkhilfe {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 10px;
}

.deck-overview {
    padding: 20px;
}
.deck-overview h2 { margin: 0 0 12px; font-size: 1rem; }
.overview-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 10px;
}
.overview-item {
    border: 1px solid var(--border-subtle);
    border-radius: 10px;
    padding: 10px;
}
.overview-item span { display: block; color: var(--text-muted); font-size: 0.75rem; }
.overview-item strong { font-size: 1.1rem; color: var(--text-main); }
.overview-new { border-color: var(--accent-blue); }
.overview-due { border-color: var(--color-6); }
.overview-mature { border-color: var(--color-1); }

.chapter-list {
    display: grid;
    gap: 10px;
    padding-bottom: 10px;
}
.chapter-btn {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 18px;
    color: var(--text-main);
    cursor: pointer;
}
.chapter-btn:hover { border-color: var(--accent-blue); }
.omnireview-btn {
    border-color: var(--accent-blue);
    background: var(--bg-surface-elevated);
}
.chapter-meta { color: var(--text-muted); font-size: 0.82rem; }

#deck-overview-view {
    display: flex;
    flex-direction: column;
    gap: 20px;
    overflow: hidden;
    position: relative;
}

.dashboard-grid {
    display: grid;
    grid-template-columns: minmax(210px, 280px) 1fr;
    gap: 12px;
}

.dashboard-card {
    padding: 14px;
}
.dashboard-label {
    color: var(--text-muted);
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 10px;
}
.muted-text { color: var(--text-muted); font-size: 0.82rem; }
.grade-value {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.srs-bars {
    display: flex;
    flex-direction: column;
    gap: 12px;
    width: 100%;
}
.srs-bar-item {
    display: grid;
    grid-template-columns: 28px 1fr 34px;
    align-items: center;
    gap: 10px;
    width: 100%;
}
.srs-bar-value,
.srs-bar-label {
    font-size: 0.86rem;
    color: #b6b6b6;
    font-weight: 600;
}
.srs-bar-label {
    text-align: left;
}
.srs-bar-value {
    text-align: right;
}
.srs-bar-track {
    width: 100%;
    height: 22px;
    border-radius: 999px;
    background: var(--srs-track-bg);
    border: 1px solid var(--border-strong);
    overflow: hidden;
}
.srs-bar {
    height: 100%;
    min-width: 0;
    border-radius: 999px;
    border: none;
}
.srs-bar.deck-level-neu { background: var(--accent-blue); }
.srs-bar.deck-level-6 { background: #d23636; }
.srs-bar.deck-level-5 { background: #f08f8f; }
.srs-bar.deck-level-4 { background: #cc6310; }
.srs-bar.deck-level-3 { background: #d8b22f; }
.srs-bar.deck-level-2 { background: #74cf8f; }
.srs-bar.deck-level-1 { background: #1f8f49; }

.gallery-shell {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    min-height: 0;
}
.gallery-top-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}
.deck-search-pill {
    max-width: 420px;
    border-radius: 999px;
    border: 1px solid var(--border-subtle);
    background: var(--bg-input);
    color: var(--text-main);
}
.deck-search-pill:focus {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px rgba(63, 127, 255, 0.2);
}
.gallery-counter {
    color: var(--text-muted);
    font-size: 0.9rem;
}
.gallery-header {
    color: var(--text-main);
    font-size: 0.95rem;
    font-weight: 600;
}

.deck-card-list {
    display: flex;
    gap: 12px;
    overflow-x: auto;
    overflow-y: hidden;
    padding-bottom: 8px;
    min-height: 154px;
}
.deck-gallery-card {
    min-width: 210px;
    height: 140px;
    padding: 14px 12px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    border-top-width: 3px;
}
.deck-gallery-latin {
    text-align: center;
    color: var(--text-main);
    font-size: 1.18rem;
    font-weight: 560;
}
.deck-level-tag {
    position: absolute;
    top: 10px;
    right: 12px;
    font-weight: 700;
    font-size: 0.95rem;
}
.deck-card-empty {
    min-width: 260px;
    padding: 30px 14px;
    border-radius: 10px;
    background: var(--bg-surface-elevated);
    border: 1px dashed var(--border-strong);
    color: var(--text-muted);
}

.deck-level-neu { border-top-color: var(--color-neu); color: var(--accent-blue); }
.deck-level-6 { border-top-color: var(--color-6); color: var(--color-6); }
.deck-level-5 { border-top-color: var(--color-5); color: var(--color-5); }
.deck-level-4 { border-top-color: var(--color-4); color: var(--color-4); }
.deck-level-3 { border-top-color: var(--color-3); color: var(--color-3); }
.deck-level-2 { border-top-color: var(--color-2); color: var(--color-2); }
.deck-level-1 { border-top-color: var(--color-1); color: var(--color-1); }

.lernen-floating-btn {
    position: fixed;
    right: 30px;
    bottom: 24px;
    border: none;
    background: var(--accent-blue);
    color: var(--text-main);
    border-radius: 999px;
    padding: 13px 22px;
    font-weight: 650;
    font-size: 0.96rem;
    box-shadow: 0 10px 20px rgba(20, 38, 84, 0.45);
    cursor: pointer;
}
.lernen-floating-btn:hover { background: #2f69df; }

/* Session styles */
.card-stack { width: min(92vw, 760px); margin: 0 auto; }
.progress-label {
    text-align: right;
    margin: 0 4px 10px;
    color: var(--text-muted);
    font-size: 0.85rem;
}
.card { width: 100%; cursor: pointer; }
.card-face {
    width: 100%;
    min-height: clamp(260px, 46vh, 430px);
    max-height: 70vh;
    overflow-y: auto;
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 14px;
    padding: clamp(22px, 5vw, 44px);
    text-align: center;
}
.card:not(.is-flipped) .card-front { display: flex; }
.card.is-flipped .card-back { display: flex; }
.card-front h2, .card-back h2 {
    font-size: clamp(1.75rem, 5vw, 3.1rem);
    line-height: 1.14;
    overflow-wrap: anywhere;
    hyphens: auto;
}
.card-front h2 { color: var(--text-main); font-weight: 670; letter-spacing: -0.01em; }
.card-back h2 { color: var(--text-latin); margin-bottom: 2px; font-weight: 700; }
.card-status-new .card-front,
.card-status-new .card-back { border-color: var(--accent-blue); }
.card-status-due .card-front,
.card-status-due .card-back { border-color: var(--color-6); }
.card-status-mature .card-front,
.card-status-mature .card-back { border-color: var(--color-1); }

/* Merkhilfe (Mnemonic) */
.merkhilfe { 
    background: var(--bg-surface-elevated);
    color: var(--text-main);
    padding: 13px 18px;
    font-size: 0.98rem;
    line-height: 1.5;
    border-left: 3px solid var(--accent-blue);
    max-width: min(100%, 620px);
    overflow-wrap: anywhere; hyphens: auto;
}

.controls {
    margin: 26px auto 8px auto;
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 8px;
    width: min(92vw, 760px);
}
.btn-rate {
    padding: 14px 10px;
    border-radius: 12px;
    border: none;
    color: white;
    font-weight: 650;
    font-size: 0.95rem;
    cursor: pointer;
}
.btn-again { background: #d53a3a; }
.btn-hard { background: #cc6310; }
.btn-good { background: #2f7ad9; }
.btn-easy { background: #2e9e58; }
.hidden { display: none !important; }

@media (max-width: 1000px) {
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 700px) {

    /* Mobile smartphone viewport adjustments */
    .bg-layer {
        grid-template-columns: 1fr;
        grid-template-rows: 1fr 1fr;
    }
    .deck-card-list {
        -webkit-overflow-scrolling: touch;
    }
    .tabs-nav li {
        padding: 12px 8px;
    }
    .back-btn, .kk-menu-btn, .omni-start-btn {
        min-height: 44px;
    }
    .btn-rate {
        min-height: 52px;
    }
    .container {
        width: 95%;
        padding: 1.2rem;
    }
    .theme-toggle-btn {
        top: 15px;
        right: 15px;
        width: 44px;
        height: 44px;
    }

    .kk-shell {
        padding: 12px;
        gap: 12px;
    }
    .kk-top-nav {
        grid-template-columns: 1fr auto;
        grid-template-areas:
            "left right"
            "title title";
        row-gap: 8px;
    }
    .kk-nav-left { grid-area: left; }
    .kk-menu-btn { grid-area: right; }
    .kk-nav-title { grid-area: title; }
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    .gallery-top-row {
        flex-direction: column;
        align-items: stretch;
    }
    .deck-search-pill {
        max-width: none;
        width: 100%;
    }
    .deck-gallery-card {
        min-width: 180px;
        height: 125px;
    }
    .card-face { min-height: clamp(230px, 44vh, 360px); max-height: 68vh; }
    .overview-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .controls { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .lernen-floating-btn {
        right: 14px;
        bottom: 14px;
    }
}

/* Tabs Navigation */
.tabs-nav {
  display: flex;
  gap: 20px;
  list-style: none;
  position: relative;
  align-items: center;
  margin: 0;
  padding: 0;
}
.tabs-nav::before {
  content: '';
  position: absolute;
  position-anchor: --active-tab;
  inset-block-start: calc(anchor(bottom) + 0.3rem);
  inset-inline-start: anchor(left);
  inset-inline-end: anchor(right);
  block-size: 3px;
  background: var(--accent-blue);
  border-radius: 3px;
}
@media (prefers-reduced-motion: no-preference) {
  .tabs-nav::before {
    transition: inset 0.15s ease-out;
  }
}
.tabs-nav li {
  cursor: pointer;
  padding: 6px 4px;
  color: var(--text-muted);
  font-weight: 600;
  transition: color 0.15s;
  font-size: 1.05rem;
}
.tabs-nav li:hover {
  color: var(--text-muted);
}
.tabs-nav li.active {
  anchor-name: --active-tab;
  color: var(--text-main);
}
@supports not (position-anchor: auto) {
  .tabs-nav::before { display: none; }
  .tabs-nav li.active {
    border-bottom: 3px solid #3f7fff;
  }
}

/* Tab Content */
.tab-panel {
    display: none;
    animation: fadeIn 0.2s ease-in-out;
}
.tab-panel.active-panel {
    display: block;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Deck Overview List */
.deck-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.deck-list-item {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 16px;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr auto;
    align-items: center;
    gap: 15px;
    transition: border-color 0.15s;
}
.deck-list-item:hover {
    border-color: var(--accent-blue);
}
.deck-name {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text-main);
}
.deck-stat {
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.deck-stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
}
.deck-stat-val {
    font-size: 1.05rem;
    color: var(--text-main);
    font-weight: 500;
}
.deck-action-btn {
    background: var(--bg-surface-elevated);
    color: var(--accent-blue);
    border: 1px solid #3f7fff;
    border-radius: 8px;
    padding: 8px 16px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.15s;
}
.deck-action-btn:hover {
    background: var(--accent-blue);
    color: var(--text-main);
}

/* Omnireview Panel */
.omni-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}
.omni-start-btn {
    background: var(--accent-blue);
    color: var(--text-main);
    border: none;
    padding: 12px 24px;
    border-radius: 10px;
    font-size: 1.05rem;
    font-weight: 650;
    cursor: pointer;
    transition: background 0.15s;
}
.omni-start-btn:hover {
    background: #2f69df;
}
.omni-start-btn:disabled {
    background: var(--bg-surface-elevated);
    color: var(--text-muted);
    cursor: not-allowed;
}
.omni-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px;
}
.checkbox-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    user-select: none;
    color: var(--text-main);
    font-weight: 500;
}
.checkbox-item:hover {
    background: var(--bg-surface-elevated);
}
.checkbox-item input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--accent-blue);
    cursor: pointer;
}

@media (max-width: 700px) {
    .deck-list-item {
        grid-template-columns: 1fr 1fr;
        grid-template-areas: 
            "name name"
            "stat1 stat2"
            "stat3 btn";
        gap: 10px;
    }
    .deck-name { grid-area: name; }
    .deck-stat:nth-child(2) { grid-area: stat1; }
    .deck-stat:nth-child(3) { grid-area: stat2; }
    .deck-stat:nth-child(4) { grid-area: stat3; }
    .deck-action-btn { grid-area: btn; align-self: center; justify-self: end; }
    
    .tabs-nav {
        gap: 12px;
    }
    .tabs-nav li {
        font-size: 0.95rem;
    }
}

/* --- WARNING BANNER --- */
.warning-banner {
    background: var(--warning-bg);
    border-left: 4px solid #dc3545;
    color: var(--warning-text);
    padding: 12px 16px;
    margin: 15px auto;
    border-radius: 4px;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 10px;
    max-width: 600px;
    box-sizing: border-box;
}
.warning-banner::before {
    content: "⚠️";
    font-size: 1.2rem;
}

/* --- LOADING OVERLAY --- */
.loading-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: var(--bg-overlay);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    color: var(--text-main);
    text-align: center;
    padding: 20px;
    box-sizing: border-box;
}
.loading-overlay.hidden {
    display: none;
}
.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid rgba(255,255,255,0.1);
    border-top-color: #2b7bc2;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}