/* style.css — hangul flashcard app */

/* ---------------------------------------------------------------
   Self-hosted Noto Sans KR — variable font, Latin + Hangul subset
   Covers weights 100–900 from a single 59KB woff2 file.
--------------------------------------------------------------- */
@font-face {
    font-family: 'Noto Sans KR';
    font-style: normal;
    font-weight: 100 900;
    font-display: swap;
    src: url('fonts/NotoSansKR.woff2') format('woff2');
    unicode-range: U+0000-00FF,U+3131-3132,U+3134,U+3137-3139,U+3141-3143,U+3145-3163,U+AE30,U+B8CC,U+BAA8,U+BCF8,U+C30D,U+C644,U+C74C,U+C774,U+C790,U+C911;
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* ---------------------------------------------------------------
   Light theme (default)
--------------------------------------------------------------- */
:root {
    --bg:           #f5f5f0;
    --surface:      #ffffff;
    --border:       #ddddd8;
    --text:         #1a1a1a;
    --text-muted:   #666660;
    --accent:       #8a3c2c;
    --accent-hover: #6e2e1e;
    --wrong:        #c0392b;
    --correct:      #27ae60;
    --radius:       10px;
    --shadow:       0 2px 8px rgba(0,0,0,0.08);

    /* feedback backgrounds */
    --correct-bg:   #eafaf1;
    --wrong-bg:     #fdf0ef;
    --option-hover-bg: #f8f0ee;

    /* hamburger menu */
    --menu-bg:      #ffffff;
    --menu-overlay: rgba(0,0,0,0.3);
}

/* ---------------------------------------------------------------
   Dark theme
--------------------------------------------------------------- */
[data-theme="dark"] {
    --bg:           #1e1e24;
    --surface:      #2a2a33;
    --border:       #3a3a46;
    --text:         #e8e8f0;
    --text-muted:   #8888a0;
    --accent:       #c0604a;
    --accent-hover: #d4735e;
    --wrong:        #e05a4e;
    --correct:      #3dbb6e;
    --shadow:       0 2px 8px rgba(0,0,0,0.4);

    --correct-bg:   #1a3328;
    --wrong-bg:     #331a1a;
    --option-hover-bg: #2e1e1a;

    --menu-bg:      #2a2a33;
    --menu-overlay: rgba(0,0,0,0.6);
}

/* ---------------------------------------------------------------
   Base
--------------------------------------------------------------- */
body {
    font-family: 'Noto Sans KR', 'Noto Sans', 'Apple SD Gothic Neo', sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem 1rem;
    transition: background 0.2s, color 0.2s;
}

/* ---------------------------------------------------------------
   Header
--------------------------------------------------------------- */
header {
    width: 100%;
    max-width: 600px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 1.1rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    color: var(--text-muted);
}

header span {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ---------------------------------------------------------------
   Hamburger button
--------------------------------------------------------------- */
.hamburger {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.25rem;
    display: flex;
    flex-direction: column;
    gap: 5px;
    margin-right: 0.75rem;
    flex-shrink: 0;
}

.hamburger span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-muted);
    border-radius: 2px;
    transition: background 0.15s;
    font-size: inherit;
    color: inherit;
}

.hamburger:hover span {
    background: var(--text);
}

.header-left {
    display: flex;
    align-items: center;
}

/* ---------------------------------------------------------------
   Slide-out menu
--------------------------------------------------------------- */
.menu-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: var(--menu-overlay);
    z-index: 100;
}

.menu-overlay.open {
    display: block;
}

.menu-panel {
    position: fixed;
    top: 0;
    left: -280px;
    width: 260px;
    height: 100vh;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    background: var(--menu-bg);
    border-right: 1px solid var(--border);
    box-shadow: 2px 0 12px rgba(0,0,0,0.15);
    z-index: 101;
    transition: left 0.25s ease;
    padding: 1.5rem 0;
}

.menu-panel.open {
    left: 0;
}

.menu-header {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    padding: 0 1.25rem 0.75rem;
    border-bottom: 1px solid var(--border);
    margin-bottom: 0.5rem;
}

.menu-item {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.25rem;
    font-size: 0.95rem;
    color: var(--text);
    text-decoration: none;
    background: none;
    border: none;
    width: 100%;
    text-align: left;
    cursor: pointer;
    font-family: inherit;
    transition: background 0.15s;
}

.menu-item:hover {
    background: var(--option-hover-bg);
}

.menu-item-icon {
    font-size: 1.1rem;
    width: 1.5rem;
    text-align: center;
}

.menu-divider {
    flex-shrink: 0;
    height: 1px;
    background: var(--border);
    margin: 0.5rem 0;
}

.menu-item.danger {
    color: var(--wrong);
}

/* Theme toggle row */
.menu-item-toggle {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.25rem;
}

.menu-item-toggle-left {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.95rem;
    color: var(--text);
}

.toggle-switch {
    position: relative;
    width: 40px;
    height: 22px;
    flex-shrink: 0;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    inset: 0;
    background: var(--border);
    border-radius: 22px;
    cursor: pointer;
    transition: background 0.2s;
}

.toggle-slider:before {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    left: 3px;
    top: 3px;
    background: white;
    border-radius: 50%;
    transition: transform 0.2s;
}

.toggle-switch input:checked + .toggle-slider {
    background: var(--accent);
}

.toggle-switch input:checked + .toggle-slider:before {
    transform: translateX(18px);
}

/* ---------------------------------------------------------------
   Segmented control (answer option count)
--------------------------------------------------------------- */
.seg-control {
    display: flex;
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.seg-btn {
    flex: 1;
    padding: 0.45rem 0;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    transition: background 0.15s, color 0.15s;
}

.seg-btn + .seg-btn {
    border-left: 1.5px solid var(--border);
}

.seg-btn.active {
    background: var(--accent);
    color: #fff;
}

.seg-btn:not(.active):hover {
    background: var(--option-hover-bg);
    color: var(--text);
}

/* ---------------------------------------------------------------
   Card
--------------------------------------------------------------- */
.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 600px;
    padding: 2.5rem 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
}

.hangul-display {
    font-size: 7rem;
    line-height: 1;
    user-select: none;
}

.prompt {
    font-size: 0.95rem;
    color: var(--text-muted);
    letter-spacing: 0.02em;
}

/* ---------------------------------------------------------------
   Multiple choice options
--------------------------------------------------------------- */
.options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    width: 100%;
}

.option-btn {
    background: var(--surface);
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    padding: 0.85rem 1rem;
    font-family: inherit;
    font-size: 1.1rem;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s;
    color: var(--text);
}

.option-btn:hover:not(:disabled) {
    border-color: var(--accent);
    background: var(--option-hover-bg);
}

.option-btn.correct {
    border-color: var(--correct);
    background: var(--correct-bg);
    color: var(--correct);
    font-weight: 600;
}

.option-btn.wrong {
    border-color: var(--wrong);
    background: var(--wrong-bg);
    color: var(--wrong);
}

.option-btn:disabled {
    cursor: default;
}

/* ---------------------------------------------------------------
   Feedback banner
--------------------------------------------------------------- */
.feedback-banner {
    width: 100%;
    padding: 0.65rem 1rem;
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-weight: 600;
    text-align: center;
}

.feedback-banner.correct {
    background: var(--correct-bg);
    color: var(--correct);
    border: 1px solid var(--correct);
}

.feedback-banner.wrong {
    background: var(--wrong-bg);
    color: var(--wrong);
    border: 1px solid var(--wrong);
}

/* ---------------------------------------------------------------
   Typed input + submit button
--------------------------------------------------------------- */
.typed-input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-family: inherit;
    font-size: 1.1rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    color: var(--text);
    background: var(--surface);
    outline: none;
    transition: border-color 0.15s;
}

.typed-input:focus {
    border-color: var(--accent);
}

.submit-btn {
    width: 100%;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    padding: 0.75rem 1rem;
    font-family: inherit;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.15s;
    margin-top: 0.25rem;
}

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

/* ---------------------------------------------------------------
   Stats bar
--------------------------------------------------------------- */
.stats-bar {
    width: 100%;
    max-width: 600px;
    display: flex;
    justify-content: space-between;
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-top: 1.25rem;
    padding: 0 0.25rem;
}

/* ---------------------------------------------------------------
   Progress bar (fixed-length sessions)
--------------------------------------------------------------- */
.progress-wrap {
    width: 100%;
    max-width: 600px;
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
    margin-top: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: var(--accent);
    border-radius: 2px;
    transition: width 0.3s ease;
}

/* End Session button (endless mode) */
.end-session-wrap {
    width: 100%;
    max-width: 600px;
    text-align: center;
    margin-top: 0.75rem;
}

.end-session-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: inherit;
    font-size: 0.8rem;
    cursor: pointer;
    text-decoration: underline;
    text-decoration-color: var(--border);
    padding: 0.25rem 0.5rem;
    transition: color 0.15s;
}

.end-session-btn:hover { color: var(--text); }

/* ---------------------------------------------------------------
   Mode / length selection screen
--------------------------------------------------------------- */
.select-form {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

fieldset {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1rem 1.25rem;
}

legend {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    padding: 0 0.4rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.radio-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
    margin-top: 0.75rem;
}

#length-n-group {
    grid-template-columns: 1fr 1fr 1fr;
}

.radio-btn {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    padding: 0.6rem 0.9rem;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s;
    color: var(--text);
}

.radio-btn:hover {
    border-color: var(--accent);
    background: var(--option-hover-bg);
}

.radio-btn input[type="radio"] {
    accent-color: var(--accent);
    margin-top: 0.15rem;
    flex-shrink: 0;
}

.radio-btn small {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.15rem;
}

/* ---------------------------------------------------------------
   Summary / wrong answer table
--------------------------------------------------------------- */
.wrong-list {
    width: 100%;
}

.wrong-list-header {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 0.6rem;
}

.wrong-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 1rem;
}

.wrong-table th {
    text-align: left;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    padding: 0.4rem 0.75rem;
    border-bottom: 1px solid var(--border);
}

.wrong-table td {
    padding: 0.5rem 0.75rem;
    border-bottom: 1px solid var(--border);
    color: var(--text);
}

.wrong-table tr:last-child td {
    border-bottom: none;
}

.wrong-hangul {
    font-size: 1.4rem;
}

/* ---------------------------------------------------------------
   Legacy rules (kept for compatibility)
--------------------------------------------------------------- */
.feedback {
    font-size: 0.95rem;
    font-weight: 600;
    min-height: 1.4em;
}

.feedback.correct { color: var(--correct); }
.feedback.wrong   { color: var(--wrong); }

.next-btn {
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    padding: 0.75rem 2rem;
    font-family: inherit;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.15s;
    display: none;
}

.next-btn:hover { background: var(--accent-hover); }
.next-btn.visible { display: inline-block; }

/* ---------------------------------------------------------------
   Responsive
--------------------------------------------------------------- */
@media (max-width: 480px) {
    body           { padding: 1rem 0.75rem; }
    .card          { padding: 1.5rem 1rem; }
    .hangul-display { font-size: 5rem; }
    .options       { grid-template-columns: 1fr 1fr; }
    .menu-panel    { max-width: 85vw; }
}

@media (max-width: 400px) {
    .options-6         { grid-template-columns: 1fr 1fr; }
    #length-n-group    { grid-template-columns: 1fr 1fr; }
}

/* ---------------------------------------------------------------
   Stats page — weight badges and row highlights
--------------------------------------------------------------- */
.weight-badge {
    display: inline-block;
    padding: 0.15rem 0.5rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.weight-badge.ok {
    background: var(--correct-bg);
    color: var(--correct);
}

.weight-badge.weak {
    background: var(--wrong-bg);
    color: var(--wrong);
}

.weight-badge.new {
    background: var(--border);
    color: var(--text-muted);
}

.row-weak td {
    background: var(--wrong-bg);
}

/* ---------------------------------------------------------------
   6-option grid layout
--------------------------------------------------------------- */
.options-6 {
    grid-template-columns: 1fr 1fr 1fr;
}

/* ---------------------------------------------------------------
   Desktop mode — sidebar layout
   Activated by body.desktop class (cookie-driven)
--------------------------------------------------------------- */
.sidebar { display: none; }

.sidebar-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 1rem 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.85rem;
}

.sidebar-card-title {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    border-bottom: 1px solid var(--border);
    padding-bottom: 0.5rem;
}

.sidebar-stat { display: flex; flex-direction: column; gap: 0.15rem; }
.sidebar-stat-label { font-size: 0.75rem; color: var(--text-muted); }
.sidebar-stat-value { font-size: 1.4rem; font-weight: 600; color: var(--text); line-height: 1.1; }
.sidebar-stat-value.streak-fire { color: var(--accent); }
.sidebar-stat-value.weight-high { color: var(--wrong); }
.sidebar-stat-value.weight-ok   { color: var(--correct); }

@media (min-width: 820px) {
    body.desktop .page-wrap {
        display: flex;
        flex-direction: row;
        align-items: flex-start;
        gap: 1.5rem;
        width: 100%;
        max-width: 920px;
    }

    body.desktop .main-col {
        flex: 1;
        min-width: 0;
        display: flex;
        flex-direction: column;
        align-items: center;
    }

    body.desktop .sidebar {
        display: flex;
        flex-direction: column;
        gap: 1rem;
        width: 220px;
        flex-shrink: 0;
        padding-top: 0.25rem;
    }
}