/* English Learning — public site styles. Plain CSS, no build step.
   Design tokens ported 1:1 from the previous Next.js/Tailwind frontend. */

:root {
    /* Force a light theme everywhere, regardless of the device's dark-mode
       setting. This also keeps native form controls (inputs, radios,
       checkboxes), scrollbars and the browser chrome in light mode. */
    color-scheme: light;
    --background: #ffffff;
    --foreground: #101828;
    --surface: #ffffff;
    --surface-muted: #f5f7fa;
    --border: #e4e7ec;
    --primary: #2563eb;
    --primary-foreground: #ffffff;
    --success: #16a34a;
    --danger: #dc2626;
    --muted-foreground: #667085;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, Helvetica, sans-serif;
}

* { box-sizing: border-box; }
html, body { padding: 0; margin: 0; }
body {
    background: var(--background);
    color: var(--foreground);
    font-family: var(--font-sans);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { margin: 0 0 0.5em; line-height: 1.25; }
p { margin: 0 0 1em; }
img, svg { max-width: 100%; }

/* ---------- App shell ---------- */
.app-shell {
    display: grid;
    grid-template-columns: 1fr;
    min-height: 100vh;
}
.app-sidebar { display: none; }
.app-header {
    position: sticky; top: 0; z-index: 10;
    display: flex; align-items: center; justify-content: space-between;
    padding: 0.75rem 1rem;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}
.brand { font-weight: 700; font-size: 1.05rem; }
.brand--mobile { display: block; }
.app-main { padding: 1rem 1rem 5.5rem; max-width: 960px; width: 100%; margin: 0 auto; }

.user-menu { display: flex; align-items: center; gap: 0.75rem; font-size: 0.9rem; }
.user-menu__name { color: var(--muted-foreground); }
.user-menu__signin { color: var(--primary); font-weight: 600; }

.bottom-nav {
    position: fixed; left: 0; right: 0; bottom: 0; z-index: 20;
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding-bottom: env(safe-area-inset-bottom);
}
.nav-list { list-style: none; margin: 0; padding: 0; display: flex; }
.nav-list--bottom { width: 100%; }
.nav-list--bottom li { flex: 1; }
.nav-item {
    display: flex; flex-direction: column; align-items: center; gap: 0.15rem;
    padding: 0.5rem 0.25rem; color: var(--muted-foreground); font-size: 0.7rem;
}
.nav-item__icon { width: 22px; height: 22px; }
.nav-item--active { color: var(--primary); }

@media (min-width: 768px) {
    .app-shell { grid-template-columns: 14rem 1fr; grid-template-rows: auto 1fr; }
    .app-sidebar {
        display: flex; flex-direction: column; gap: 1.5rem;
        padding: 1.25rem 1rem; position: sticky; top: 0; height: 100vh;
        border-right: 1px solid var(--border); background: var(--surface);
        grid-column: 1; grid-row: 1 / -1;
    }
    .app-header { grid-column: 2; grid-row: 1; }
    .app-main { grid-column: 2; grid-row: 2; }
    .app-sidebar .nav-list { flex-direction: column; gap: 0.25rem; }
    .app-sidebar .nav-item { flex-direction: row; justify-content: flex-start; gap: 0.65rem; font-size: 0.9rem; padding: 0.5rem 0.6rem; border-radius: 0.5rem; }
    .app-sidebar .nav-item--active { background: var(--surface-muted); }
    .app-sidebar .nav-item__icon { width: 18px; height: 18px; }
    .brand--mobile { display: none; }
    .bottom-nav { display: none; }
    .app-main { padding: 1.5rem 2rem; }
}

/* ---------- Alerts ---------- */
.alert { padding: 0.75rem 1rem; border-radius: 0.5rem; margin-bottom: 1rem; font-size: 0.9rem; }
.alert--success { background: rgba(22,163,74,0.1); color: var(--success); }
.alert--error { background: rgba(220,38,38,0.1); color: var(--danger); }

/* ---------- Buttons & forms ---------- */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 0.4rem;
    padding: 0.55rem 1rem; border-radius: 0.5rem; border: 1px solid var(--border);
    background: var(--surface); color: var(--foreground); font-size: 0.9rem; cursor: pointer;
}
.btn:disabled { opacity: 0.6; cursor: not-allowed; }
.btn--primary { background: var(--primary); color: var(--primary-foreground); border-color: var(--primary); }
.btn--success { background: var(--success); color: #fff; border-color: var(--success); }
.btn--block { width: 100%; }
.link-button { background: none; border: none; color: inherit; cursor: pointer; padding: 0; font: inherit; }

.field { margin-bottom: 1rem; }
.field label { display: block; font-size: 0.85rem; margin-bottom: 0.3rem; color: var(--muted-foreground); }
.field input, .field select, .field textarea {
    width: 100%; padding: 0.55rem 0.7rem; border-radius: 0.5rem; border: 1px solid var(--border);
    background: var(--surface); color: var(--foreground); font-size: 0.95rem;
}
.field-row { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.field-row .field { flex: 1; min-width: 140px; }
.inline-form { display: inline; }

.auth-card { max-width: 380px; margin: 2rem auto; background: var(--surface); border: 1px solid var(--border); border-radius: 0.75rem; padding: 1.75rem; }
.auth-card h1 { font-size: 1.35rem; }
.auth-card__footer { font-size: 0.85rem; color: var(--muted-foreground); margin-top: 1rem; text-align: center; }

/* ---------- Cards / grids ---------- */
.card-grid { display: grid; grid-template-columns: 1fr; gap: 0.9rem; }
@media (min-width: 640px) { .card-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 768px) { .card-grid { grid-template-columns: repeat(3, 1fr); } }

.card {
    display: block; padding: 1rem; border: 1px solid var(--border); border-radius: 0.75rem;
    background: var(--surface);
}
.card h3 { font-size: 1rem; margin-bottom: 0.25rem; }
.card p { margin: 0; color: var(--muted-foreground); font-size: 0.85rem; }

.stat-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.75rem; margin: 1rem 0; }
@media (min-width: 640px) { .stat-grid { grid-template-columns: repeat(4, 1fr); } }
.stat-tile { background: var(--surface-muted); border-radius: 0.75rem; padding: 0.9rem; text-align: center; }
.stat-tile__value { font-size: 1.4rem; font-weight: 700; }
.stat-tile__label { font-size: 0.75rem; color: var(--muted-foreground); }

.badge { display: inline-block; padding: 0.15rem 0.55rem; border-radius: 999px; font-size: 0.75rem; }
.badge--muted { background: var(--surface-muted); color: var(--muted-foreground); }
.badge--success { background: rgba(22,163,74,0.12); color: var(--success); }
.badge--danger { background: rgba(220,38,38,0.12); color: var(--danger); }
.badge--primary { background: rgba(37,99,235,0.12); color: var(--primary); }

.empty-state { color: var(--muted-foreground); padding: 2rem 0; text-align: center; }

.back-link { display: inline-block; margin-bottom: 1rem; color: var(--muted-foreground); font-size: 0.9rem; }

.section { margin-bottom: 1.75rem; }
.section-title { font-size: 1.05rem; margin-bottom: 0.6rem; }

.rich-text > * + * { margin-top: 0.7rem; }
.rich-text h1 { font-size: 1.5rem; font-weight: 700; }
.rich-text h2 { font-size: 1.25rem; font-weight: 700; }
.rich-text h3 { font-size: 1.1rem; font-weight: 700; }
.rich-text ul, .rich-text ol { padding-left: 1.4rem; }
.rich-text blockquote { border-left: 3px solid var(--border); padding-left: 0.9rem; color: var(--muted-foreground); }
.rich-text code { background: var(--surface-muted); padding: 0.1rem 0.3rem; border-radius: 0.25rem; font-size: 0.9em; }
.rich-text pre { background: #0d1117; color: #e6edf3; padding: 0.8rem 1rem; border-radius: 0.5rem; overflow-x: auto; }
.rich-text pre code { background: none; color: inherit; padding: 0; }
.rich-text a { color: var(--primary); text-decoration: underline; }
.rich-text hr { border: none; border-top: 2px solid var(--border); margin: 1rem 0; }

.chip-list { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.chip { background: var(--surface-muted); border-radius: 999px; padding: 0.25rem 0.7rem; font-size: 0.85rem; }
.chip a { color: var(--primary); }

.filter-form { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-bottom: 1.25rem; align-items: flex-end; }
.filter-form .field { margin-bottom: 0; flex: 1; min-width: 140px; }
.filter-form .btn { height: 2.5rem; }

.pagination { display: flex; align-items: center; justify-content: space-between; margin-top: 1.25rem; font-size: 0.9rem; }
.pagination__link { color: var(--primary); }
.pagination__link--disabled { color: var(--muted-foreground); opacity: 0.5; }
.pagination__status { color: var(--muted-foreground); }

/* ---------- Vocabulary / grammar detail ---------- */
.word-head { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.word-head__ipa { color: var(--muted-foreground); }
.pronounce-btn {
    display: inline-flex; align-items: center; justify-content: center;
    width: 2.1rem; height: 2.1rem; border-radius: 999px; border: 1px solid var(--border);
    background: var(--surface); cursor: pointer;
}
.action-bar { display: flex; gap: 0.6rem; margin: 1rem 0; }

.mistake { border-left: 3px solid var(--border); padding-left: 0.75rem; margin-bottom: 0.75rem; }
.mistake__wrong { color: var(--danger); text-decoration: line-through; }
.mistake__correct { color: var(--success); }
.mistake__note { color: var(--muted-foreground); font-size: 0.85rem; }

/* ---------- Test runner ---------- */
.passage-box { background: var(--surface-muted); border-radius: 0.75rem; padding: 1rem; margin-bottom: 1rem; white-space: pre-wrap; }
.question-nav { display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 1rem 0; }
.question-nav__item {
    width: 2rem; height: 2rem; border-radius: 999px; border: 1px solid var(--border);
    background: var(--surface); display: flex; align-items: center; justify-content: center;
    font-size: 0.8rem; cursor: pointer; color: var(--foreground);
}
.question-nav__item--current { background: var(--primary); color: var(--primary-foreground); border-color: var(--primary); }
.question-nav__item--answered { background: var(--surface-muted); }

.option-list { display: flex; flex-direction: column; gap: 0.6rem; margin: 1rem 0; }
.option-btn {
    display: flex; align-items: center; gap: 0.75rem; text-align: left;
    padding: 0.75rem 1rem; border-radius: 0.6rem; border: 1px solid var(--border);
    background: var(--surface); cursor: pointer; font-size: 0.95rem;
}
.option-btn--selected { border-color: var(--primary); background: rgba(37,99,235,0.08); }
.option-btn__label {
    width: 1.6rem; height: 1.6rem; border-radius: 999px; border: 1px solid var(--border);
    display: flex; align-items: center; justify-content: center; font-size: 0.8rem; flex-shrink: 0;
}
.option-btn--selected .option-btn__label { background: var(--primary); color: var(--primary-foreground); border-color: var(--primary); }

.test-actions { display: flex; justify-content: space-between; margin-top: 1.25rem; }

.review-item { border: 1px solid var(--border); border-radius: 0.75rem; padding: 1rem; margin-bottom: 0.9rem; }
.review-item__answer--wrong { color: var(--danger); }
.review-item__answer--correct { color: var(--success); }
.review-item__explanation { color: var(--muted-foreground); font-size: 0.9rem; margin-top: 0.5rem; }