/* ============ Base ============ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #ffffff;
    color: #333333;
    min-height: 100vh;
    padding: 16px;
    line-height: 1.5;
}

.container {
    max-width: 720px;
    margin: 0 auto;
}

/* ============ Dark mode ============ */
@media (prefers-color-scheme: dark) {
    body {
        background: #111111;
        color: #e0e0e0;
    }
    .back-link {
        background: #111111;
    }
    .topic-card, .scenario-item, .scenario {
        background: #1e1e1e;
        box-shadow: 0 4px 15px rgba(0,0,0,0.4);
    }
    .dialogue {
        background: #2a2a2a;
    }
    .english { color: #ffffff; }
    .korean { color: #aaaaaa; }
    .speaker { color: #8ab4f8; }
    .topic-title, .scenario-name { color: #ffffff; }
    .topic-subtitle, .scenario-desc { color: #999999; }
    .topic-count, .scenario-count { background: #3a3a3a; color: #cccccc; }
    footer { color: #666666; }
}

/* ============ Header ============ */
header {
    text-align: center;
    margin-bottom: 24px;
    padding-top: 8px;
}

/* Back-link: sticky full-width bar at top */
.back-link {
    display: block;
    color: #667eea;
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    padding: 12px 4px;
    position: sticky;
    top: 0;
    background: #ffffff;
    z-index: 100;
    border-bottom: 1px solid #eef0ff;
}

.back-link:hover {
    text-decoration: underline;
}

/* Breadcrumb separator between nav links */
.nav-sep {
    color: #aaa;
    font-size: 1rem;
    padding: 0 4px;
    line-height: 1;
}

.back-nav {
    display: flex;
    gap: 2px;
    flex-wrap: wrap;
    align-items: center;
}

.back-nav .back-link {
    display: inline-block;
    vertical-align: middle;
    padding: 8px 6px;
    line-height: 1;
}

@media (prefers-color-scheme: dark) {
    .back-link {
        background: #111111;
    }
}

/* Dialogue pages: back-links + control bar stay together in a sticky container */
.sticky-top {
    position: sticky;
    top: 0;
    background: #ffffff;
    z-index: 100;
    padding: 6px 0;
    border-bottom: 1px solid #eef0ff;
}

.sticky-top .back-link {
    position: static;
    padding: 8px 12px;
    border-bottom: none;
}

.back-nav {
    display: flex;
    gap: 2px;
    flex-wrap: wrap;
    align-items: center;
}

/* Nav row: breadcrumb left, done button right */
.nav-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
}

.nav-row .done-btn {
    flex-shrink: 0;
    margin-left: auto;
}

/* Control bar: sticks below the back-nav bar */
.sticky-controls {
    position: sticky;
    top: 44px;
    background: #ffffff;
    z-index: 99;
    border-bottom: 1px solid #eef0ff;
}

@media (prefers-color-scheme: dark) {
    .sticky-controls { background: #111111; }
}

.sticky-controls .control-bar {
    position: static;
    margin-bottom: 0;
    padding: 6px 4px 8px;
}

@media (prefers-color-scheme: dark) {
    .sticky-top { background: #111111; }
    .sticky-top .back-link { background: transparent; }
}

/* ============ Main page cards ============ */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 14px;
}

.topic-card {
    background: #ffffff;
    border-radius: 16px;
    padding: 20px;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    transition: transform 0.2s, box-shadow 0.2s;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.topic-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.12);
}

.topic-icon { font-size: 2.8em; }
.topic-title { font-size: 1.5rem; font-weight: 700; color: #333333; }
.topic-subtitle { font-size: 1rem; color: #777777; }
.topic-count {
    font-size: 0.95rem;
    font-weight: 600;
    color: #667eea;
    background: #eef0ff;
    padding: 5px 12px;
    border-radius: 12px;
    display: inline-block;
    width: fit-content;
    margin-top: 4px;
}

/* ============ Scenario list page ============ */
.scenario-list {
    display: grid;
    gap: 12px;
}

.scenario-item {
    background: #ffffff;
    border-radius: 14px;
    padding: 16px;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 3px 12px rgba(0,0,0,0.08);
    transition: transform 0.2s, box-shadow 0.2s;
    display: flex;
    align-items: center;
    gap: 14px;
}

.scenario-item:hover {
    transform: translateX(4px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

.scenario-icon {
    font-size: 2em;
    width: 54px;
    height: 54px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.scenario-info { flex: 1; min-width: 0; }
.scenario-name { font-size: 1.3rem; font-weight: 700; color: #333333; margin-bottom: 3px; }
.scenario-desc { font-size: 1rem; color: #777777; }
.scenario-count {
    font-size: 0.9rem;
    font-weight: 600;
    color: #667eea;
    background: #eef0ff;
    padding: 5px 12px;
    border-radius: 12px;
    white-space: nowrap;
}

/* ============ Dialogue page ============ */
.scenario {
    background: #ffffff;
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.dialogue {
    position: relative;
    padding: 14px;
    margin-bottom: 12px;
    background: #f7f8fa;
    border-radius: 12px;
    border-left: 4px solid #667eea;
    cursor: pointer;
    transition: background 0.2s;
}

.dialogue:last-child { margin-bottom: 0; }
.dialogue:hover { background: #eef0ff; }
.dialogue.playing {
    background: #e8f5e9;
    border-left-color: #4caf50;
}

.speaker {
    font-weight: 700;
    color: #667eea;
    font-size: 0.85rem;
    margin-bottom: 6px;
}

.dialogue.playing .speaker { color: #4caf50; }

.english {
    font-size: 1.15rem;
    color: #333333;
    margin-bottom: 6px;
}

.korean {
    font-size: 0.95rem;
    color: #888888;
}

.audio-controls { margin-top: 10px; }

audio {
    width: 100%;
    height: 32px;
    border-radius: 16px;
}

/* ============ Page nav ============ */
.page-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
    margin-top: 20px;
    border-top: 1px solid #e5e5e5;
}

.page-nav a {
    color: #667eea;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 600;
    padding: 8px 14px;
    border-radius: 10px;
    background: #eef0ff;
    transition: background 0.2s;
}

.page-nav a:hover { background: #dde1ff; }

/* ============ Footer ============ */
footer {
    text-align: center;
    color: #999999;
    margin-top: 30px;
    padding: 15px;
    font-size: 0.85rem;
}

/* ============ Responsive ============ */
@media (max-width: 600px) {
    body { padding: 12px; }
    header h1 { font-size: 1.6rem; }
    header p { font-size: 0.95rem; }
    
    .topics-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
    .topic-card { padding: 14px; }
    .topic-icon { font-size: 2.2em; }
    .topic-title { font-size: 1.2rem; }
    .topic-subtitle { font-size: 0.9rem; }
    .topic-count { font-size: 0.8rem; padding: 4px 10px; }
    
    .scenario-item { padding: 12px; gap: 10px; }
    .scenario-icon { width: 44px; height: 44px; font-size: 1.6em; }
    .scenario-name { font-size: 1.1rem; }
    .scenario-desc { font-size: 0.9rem; }
    .scenario-count { font-size: 0.8rem; padding: 4px 10px; }
    
    .scenario { padding: 14px; }
    .dialogue { padding: 12px; }
    .english { font-size: 1.1rem; }
    .korean { font-size: 0.9rem; }
    audio { height: 30px; }
    
    .page-nav { flex-direction: row; gap: 8px; }
    .page-nav a { width: 50%; text-align: center; padding: 10px 8px; }
}

@media (max-width: 380px) {
    .topics-grid { grid-template-columns: 1fr; }
}

/* ============ Study progress ============ */
.overall-progress {
    margin-bottom: 18px;
    padding: 14px 16px;
    background: #f0f3ff;
    border-radius: 14px;
    border: 1px solid #dde3ff;
}

.overall-text {
    font-size: 0.95rem;
    font-weight: 700;
    color: #4455aa;
    margin-bottom: 8px;
}

.progress-track {
    height: 8px;
    background: #e0e0e0;
    border-radius: 6px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    border-radius: 6px;
    transition: width 0.4s ease;
}

.progress-area {
    margin-bottom: 16px;
    padding: 12px 14px;
    background: #f0f3ff;
    border-radius: 12px;
    border: 1px solid #dde3ff;
}

.progress-text {
    font-size: 0.9rem;
    font-weight: 700;
    color: #4455aa;
    margin-bottom: 8px;
}

/* ============ Offline audio download (category page) ============ */
/* Three columns so the status stays centred whatever sits on the right */
.offline-area {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    min-height: 40px;
}

.offline-main {
    grid-column: 2;
    display: flex;
    align-items: center;
    gap: 8px;
}

.offline-more {
    grid-column: 3;
    justify-self: end;
    position: relative;
}

/* progress and the delete confirmation take the whole row instead */
.offline-full {
    grid-column: 1 / -1;
    justify-self: stretch;
}

.offline-more-btn {
    width: 34px;
    height: 34px;
    border-radius: 10px;
    border: 1px solid #dddddd;
    background: transparent;
    color: #888888;
    font-size: 1.1rem;
    line-height: 1;
    font-family: inherit;
    cursor: pointer;
}

.offline-more-btn:hover { color: #444444; border-color: #bbbbbb; }

.offline-menu {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    min-width: 124px;
    padding: 4px;
    background: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.14);
    z-index: 30;
}

.offline-menu-item {
    display: block;
    width: 100%;
    padding: 9px 12px;
    text-align: left;
    border: none;
    border-radius: 7px;
    background: transparent;
    color: #d32f2f;
    font-size: 0.86rem;
    font-family: inherit;
    font-weight: 600;
    cursor: pointer;
}

.offline-menu-item:hover { background: #fdecea; }

.offline-confirm-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.offline-btn, .offline-done {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 14px;
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 700;
    font-family: inherit;
}

.offline-btn {
    background: #667eea;
    color: #ffffff;
    border: none;
    cursor: pointer;
    transition: background 0.2s;
}

.offline-btn:hover { background: #5568d3; }

.offline-done {
    background: #e8f5e9;
    color: #2e7d32;
    border: 1px solid #c8e6c9;
}

.offline-note {
    font-weight: 500;
    opacity: 0.8;
    font-size: 0.82rem;
}

.offline-del {
    padding: 9px 12px;
    border-radius: 10px;
    border: 1px solid #dddddd;
    background: transparent;
    color: #888888;
    font-size: 0.82rem;
    font-family: inherit;
    cursor: pointer;
}

.offline-del:hover { color: #d32f2f; border-color: #f0c0c0; }

.offline-del.danger {
    background: #d32f2f;
    border-color: #d32f2f;
    color: #ffffff;
    font-weight: 700;
}

.offline-del.danger:hover { background: #b71c1c; border-color: #b71c1c; color: #ffffff; }

.offline-cancel {
    padding: 9px 12px;
    border-radius: 10px;
    border: 1px solid #dddddd;
    background: transparent;
    color: #666666;
    font-size: 0.82rem;
    font-family: inherit;
    cursor: pointer;
}

.offline-confirm {
    font-size: 0.85rem;
    font-weight: 700;
    color: #b71c1c;
    margin-right: 2px;
}

.offline-progress { flex: 1; }

.offline-progress-text {
    font-size: 0.85rem;
    font-weight: 700;
    color: #4455aa;
    margin-bottom: 6px;
}

.offline-track {
    height: 8px;
    background: #e0e0e0;
    border-radius: 6px;
    overflow: hidden;
}

.offline-fill {
    height: 100%;
    width: 0;
    background: linear-gradient(90deg, #667eea, #764ba2);
    border-radius: 6px;
    transition: width 0.3s ease;
}

@media (prefers-color-scheme: dark) {
    .offline-done { background: #1b3a1f; color: #81c995; border-color: #2e5a33; }
    .offline-del { border-color: #444444; color: #999999; }
    .offline-cancel { border-color: #444444; color: #aaaaaa; }
    .offline-confirm { color: #f28b82; }
    .offline-more-btn { border-color: #444444; color: #999999; }
    .offline-more-btn:hover { color: #dddddd; border-color: #666666; }
    .offline-menu { background: #2a2a2a; border-color: #444444; box-shadow: 0 6px 20px rgba(0,0,0,0.5); }
    .offline-menu-item { color: #f28b82; }
    .offline-menu-item:hover { background: #3a2a2a; }
    .offline-progress-text { color: #8ab4f8; }
    .offline-track { background: #3a3a3a; }
}

.scenario-item.done {
    background: #e8f5e9;
    box-shadow: 0 3px 12px rgba(76,175,80,0.15);
}

.scenario-item.done .scenario-name {
    color: #2e7d32;
}

/* checkmark marker above count for done items */
.scenario-side {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    flex-shrink: 0;
}

.scenario-done-mark {
    font-size: 0.7rem;
    font-weight: 700;
    color: #2e7d32;
}

/* Done button (in control bar) */
.done-btn {
    flex-shrink: 0;
    padding: 8px 12px;
    border: 1px solid #cccccc;
    background: #f0f0f0;
    color: #444444;
    border-radius: 16px;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.done-btn.checked {
    border-color: #4caf50;
    background: #e8f5e9;
    color: #2e7d32;
}

@media (max-width: 600px) {
    .done-btn {
        padding: 6px 10px;
        font-size: 0.75rem;
    }
}

/* Topic card progress */
.topic-progress {
    margin-top: 8px;
}

.topic-progress-text {
    font-size: 0.75rem;
    font-weight: 600;
    color: #667eea;
    margin-bottom: 4px;
}

.topic-progress-track {
    height: 6px;
    background: #e0e0e0;
    border-radius: 4px;
    overflow: hidden;
}

.topic-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    border-radius: 4px;
    transition: width 0.4s ease;
}

@media (prefers-color-scheme: dark) {
    .overall-progress, .progress-area {
        background: #1e1e1e;
        border-color: #3a3a3a;
    }
    .overall-text, .progress-text {
        color: #8ab4f8;
    }
    .progress-track, .topic-progress-track {
        background: #3a3a3a;
    }
    .scenario-item.done {
        background: #1e2e20;
    }
    .scenario-item.done .scenario-name {
        color: #81c784;
    }
    .scenario-done-mark {
        color: #81c784;
    }
    .done-btn {
        background: #2a2a2a;
        border-color: #555555;
        color: #dddddd;
    }
    .done-btn.checked {
        background: #1e2e20;
        border-color: #81c784;
        color: #81c784;
    }
}

/* Entry point to the bookmark review page, shown on the home screen only when
   there are bookmarks to review */
.marks-link {
    display: block;
    text-align: center;
    padding: 12px;
    margin-bottom: 16px;
    background: #fff8e8;
    border: 1px solid #f5d08a;
    border-radius: 12px;
    color: #8a6300;
    font-weight: 600;
    text-decoration: none;
}

.marks-link:hover { background: #fdf0d0; }

@media (prefers-color-scheme: dark) {
    .marks-link {
        background: #2a2418;
        border-color: #6b5a2a;
        color: #f5c66a;
    }
    .marks-link:hover { background: #352d1d; }
}

/* Progress and bookmarks live in localStorage, so they do not follow the user
   to another phone or survive clearing site data. Said once on the home
   screen, quietly - it is a caveat, not a warning. */
.local-only-note {
    margin: 0 0 14px;
    padding: 10px 14px;
    background: #f4f5f9;
    border-left: 3px solid #c7cbe0;
    border-radius: 8px;
    color: #6b6f80;
    font-size: 0.82rem;
    line-height: 1.55;
}

@media (prefers-color-scheme: dark) {
    .local-only-note {
        background: #1c1c22;
        border-left-color: #45495c;
        color: #9a9eb0;
    }
}