/* ============================================
   AI Question Solver — Public CSS
   Modern, responsive, dark-mode-ready
   ============================================ */

.aiqs-root {
    --aiqs-primary: #2563eb;
    --aiqs-primary-600: #1d4ed8;
    --aiqs-accent: #7c3aed;
    --aiqs-bg: #ffffff;
    --aiqs-surface: #f8fafc;
    --aiqs-surface-2: #f1f5f9;
    --aiqs-text: #0f172a;
    --aiqs-text-muted: #64748b;
    --aiqs-border: #e2e8f0;
    --aiqs-success: #16a34a;
    --aiqs-warn: #ea580c;
    --aiqs-danger: #dc2626;
    --aiqs-radius: 14px;
    --aiqs-radius-lg: 20px;
    --aiqs-shadow: 0 1px 2px rgba(15,23,42,.04), 0 8px 24px -10px rgba(15,23,42,.08);

    font-family: 'Plus Jakarta Sans', 'Inter', -apple-system, system-ui, 'Segoe UI', sans-serif;
    color: var(--aiqs-text);
    background: var(--aiqs-bg);
    line-height: 1.55;
    box-sizing: border-box;
}
.aiqs-root *, .aiqs-root *::before, .aiqs-root *::after { box-sizing: border-box; }

.aiqs-root.aiqs-dark {
    --aiqs-bg: #0b1220;
    --aiqs-surface: #111a2e;
    --aiqs-surface-2: #17223a;
    --aiqs-text: #e2e8f0;
    --aiqs-text-muted: #94a3b8;
    --aiqs-border: #233148;
    --aiqs-shadow: 0 1px 2px rgba(0,0,0,.4), 0 12px 32px -10px rgba(0,0,0,.5);
}

/* ---- Toolbar ---- */
.aiqs-toolbar {
    display: flex; gap: 12px; flex-wrap: wrap;
    padding: 16px; background: var(--aiqs-surface);
    border: 1px solid var(--aiqs-border); border-radius: var(--aiqs-radius);
    margin-bottom: 16px;
}
.aiqs-search-wrap {
    flex: 1 1 280px; min-width: 240px;
    position: relative; display: flex; align-items: center;
}
.aiqs-search-wrap i {
    position: absolute; left: 14px; color: var(--aiqs-text-muted); pointer-events: none;
}
.aiqs-search-input {
    width: 100%; padding: 12px 14px 12px 40px;
    border: 1px solid var(--aiqs-border); border-radius: 10px;
    background: var(--aiqs-bg); color: var(--aiqs-text); font-size: 15px;
    transition: border-color .15s, box-shadow .15s;
}
.aiqs-search-input:focus { outline: none; border-color: var(--aiqs-primary); box-shadow: 0 0 0 4px rgba(37,99,235,.12); }

.aiqs-filters { display: flex; gap: 8px; flex-wrap: wrap; }
.aiqs-filter, .aiqs-lang-select {
    padding: 10px 12px; border: 1px solid var(--aiqs-border); border-radius: 10px;
    background: var(--aiqs-bg); color: var(--aiqs-text); font-size: 14px;
    cursor: pointer;
}
.aiqs-filter:focus, .aiqs-lang-select:focus { outline: none; border-color: var(--aiqs-primary); }

.aiqs-iconbtn {
    width: 40px; height: 40px; border-radius: 10px;
    border: 1px solid var(--aiqs-border); background: var(--aiqs-bg); color: var(--aiqs-text);
    cursor: pointer; transition: background .15s;
    display: inline-flex; align-items: center; justify-content: center;
}
.aiqs-iconbtn:hover { background: var(--aiqs-surface-2); }

/* ---- List items ---- */
.aiqs-list { display: grid; gap: 12px; grid-template-columns: 1fr; }
@media (min-width: 768px) { .aiqs-list { grid-template-columns: 1fr 1fr; } }

.aiqs-list-item {
    background: var(--aiqs-surface);
    border: 1px solid var(--aiqs-border);
    border-radius: var(--aiqs-radius);
    padding: 16px;
    display: flex; flex-direction: column; gap: 10px;
    transition: transform .15s, box-shadow .15s, border-color .15s;
}
.aiqs-list-item:hover { transform: translateY(-2px); box-shadow: var(--aiqs-shadow); border-color: var(--aiqs-primary); }

.aiqs-list-meta { display: flex; gap: 6px; flex-wrap: wrap; }
.aiqs-list-text { color: var(--aiqs-text); font-size: 15px; min-height: 48px; }
.aiqs-list-actions { display: flex; justify-content: space-between; align-items: center; gap: 8px; }
.aiqs-list-stats { color: var(--aiqs-text-muted); font-size: 13px; display: inline-flex; gap: 10px; align-items: center; }
.aiqs-list-stats i { margin-right: 4px; }

.aiqs-load-more-wrap { display: flex; justify-content: center; margin-top: 18px; }

/* ---- Chips ---- */
.aiqs-chip {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 4px 10px; border-radius: 999px;
    font-size: 12px; font-weight: 600;
    background: var(--aiqs-surface-2); color: var(--aiqs-text);
    border: 1px solid transparent;
}
.aiqs-chip-muted { background: var(--aiqs-surface-2); color: var(--aiqs-text-muted); }
.aiqs-chip-easy   { background: #dcfce7; color: #166534; }
.aiqs-chip-medium { background: #fef3c7; color: #92400e; }
.aiqs-chip-hard   { background: #fee2e2; color: #991b1b; }
.aiqs-dark .aiqs-chip-easy   { background: rgba(34,197,94,.18);  color: #86efac; }
.aiqs-dark .aiqs-chip-medium { background: rgba(234,179,8,.18);  color: #fde68a; }
.aiqs-dark .aiqs-chip-hard   { background: rgba(220,38,38,.22);  color: #fca5a5; }

/* ---- Question Card ---- */
.aiqs-question-card {
    background: var(--aiqs-surface);
    border: 1px solid var(--aiqs-border);
    border-radius: var(--aiqs-radius-lg);
    overflow: hidden; box-shadow: var(--aiqs-shadow);
}
.aiqs-q-header {
    display: flex; justify-content: space-between; align-items: flex-start; gap: 12px;
    padding: 18px 20px; background: var(--aiqs-surface-2);
    border-bottom: 1px solid var(--aiqs-border); flex-wrap: wrap;
}
.aiqs-q-meta { display: flex; gap: 6px; flex-wrap: wrap; }
.aiqs-q-tools { display: flex; gap: 8px; align-items: center; }

.aiqs-q-body { padding: 22px 24px; }
.aiqs-q-text { font-size: 18px; line-height: 1.55; color: var(--aiqs-text); white-space: pre-wrap; word-break: break-word; overflow-wrap: anywhere; }
.aiqs-q-image { margin-top: 14px; }
.aiqs-q-image img { max-width: 100%; border-radius: 12px; border: 1px solid var(--aiqs-border); }

.aiqs-options { list-style: none; padding: 0; margin: 18px 0 0; display: grid; gap: 10px; }
@media (min-width: 640px) { .aiqs-options { grid-template-columns: 1fr 1fr; } }
.aiqs-option {
    display: flex; align-items: center; gap: 12px;
    padding: 12px 14px; border: 2px solid var(--aiqs-border); border-radius: 12px;
    background: var(--aiqs-bg); cursor: pointer;
    transition: border-color .15s, background .15s, transform .1s;
}
.aiqs-option:hover { border-color: var(--aiqs-primary); transform: translateY(-1px); }
.aiqs-option.is-selected { border-color: var(--aiqs-primary); background: rgba(37,99,235,.06); }
.aiqs-option.is-correct  { border-color: var(--aiqs-success); background: rgba(22,163,74,.15); animation: aiqs-pulse-green .5s; }
.aiqs-option.is-wrong    { border-color: var(--aiqs-danger); background: rgba(220,38,38,.15); }
@keyframes aiqs-pulse-green { 0% { box-shadow: 0 0 0 0 rgba(22,163,74,.4); } 100% { box-shadow: 0 0 0 12px rgba(22,163,74,0); } }
.aiqs-opt-letter {
    display: inline-flex; align-items: center; justify-content: center;
    width: 32px; height: 32px; border-radius: 50%;
    background: var(--aiqs-primary); color: #fff; font-weight: 700;
    flex-shrink: 0;
}
.aiqs-option.is-correct .aiqs-opt-letter { background: var(--aiqs-success); }
.aiqs-option.is-wrong .aiqs-opt-letter { background: var(--aiqs-danger); }
.aiqs-opt-text { font-size: 15px; }

/* ---- Actions ---- */
.aiqs-q-actions {
    display: flex; gap: 10px; flex-wrap: wrap;
    padding: 16px 20px; border-top: 1px solid var(--aiqs-border);
    background: var(--aiqs-surface-2);
}

/* ---- Buttons ---- */
.aiqs-btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    padding: 10px 16px; border-radius: 10px; border: 1px solid var(--aiqs-border);
    background: var(--aiqs-bg); color: var(--aiqs-text);
    font-size: 14px; font-weight: 600; cursor: pointer;
    transition: transform .1s, background .15s, border-color .15s, box-shadow .15s;
    text-decoration: none; line-height: 1;
}
.aiqs-btn:hover { transform: translateY(-1px); border-color: var(--aiqs-primary); }
.aiqs-btn:active { transform: translateY(0); }
.aiqs-btn[disabled] { opacity: .6; cursor: not-allowed; transform: none !important; }
.aiqs-btn-sm { padding: 7px 12px; font-size: 13px; border-radius: 8px; }
.aiqs-btn-primary { background: var(--aiqs-primary); color: #fff; border-color: var(--aiqs-primary); }
.aiqs-btn-primary:hover { background: var(--aiqs-primary-600); border-color: var(--aiqs-primary-600); color: #fff; }
.aiqs-btn-ghost { background: transparent; }

.aiqs-btn-ai {
    background: linear-gradient(135deg, #7c3aed 0%, #2563eb 100%);
    color: #fff; border-color: transparent;
    box-shadow: 0 6px 18px -8px rgba(124,58,237,.6);
}
.aiqs-btn-ai:hover { transform: translateY(-1px); box-shadow: 0 10px 22px -8px rgba(124,58,237,.7); color: #fff; border-color: transparent; }
.aiqs-btn-ai i { color: #fff; }

.aiqs-btn-bookmark.is-active { background: #fef3c7; border-color: #fbbf24; color: #92400e; }
.aiqs-btn-bookmark.is-active i { color: #d97706; }
.aiqs-btn-report:hover { border-color: var(--aiqs-danger); color: var(--aiqs-danger); }

.aiqs-btn-explanation {
    background: linear-gradient(135deg, #16a34a 0%, #0d9488 100%);
    color: #fff; border-color: transparent;
    box-shadow: 0 6px 18px -8px rgba(22,163,74,.5);
}
.aiqs-btn-explanation:hover { color: #fff; border-color: transparent; box-shadow: 0 10px 22px -8px rgba(22,163,74,.6); }
.aiqs-btn-explanation i { color: #fff; }

.aiqs-explanation-block { padding: 8px 0 16px; }
.aiqs-expl-images { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 10px; margin-top: 12px; }
.aiqs-expl-images img { width: 100%; border-radius: 12px; border: 1px solid var(--aiqs-border); }

.aiqs-drop-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.aiqs-drop-btn { flex: 1 1 200px; justify-content: center; padding: 22px; border-style: dashed; cursor: pointer; }
.aiqs-drop-btn:hover { border-color: var(--aiqs-primary); background: rgba(37,99,235,.04); }
.aiqs-drop-btn i { color: var(--aiqs-primary); font-size: 20px; }

/* ---- AI Output ---- */
.aiqs-ai-output {
    border-top: 1px solid var(--aiqs-border);
    background: var(--aiqs-bg); padding: 8px 20px 20px;
}
.aiqs-accordion { border: 1px solid var(--aiqs-border); border-radius: 12px; overflow: hidden; margin-top: 12px; background: var(--aiqs-surface); }
.aiqs-acc-head {
    display: flex; justify-content: space-between; align-items: center;
    padding: 14px 18px; cursor: pointer; user-select: none;
    background: var(--aiqs-surface-2); font-weight: 700; color: var(--aiqs-text);
    transition: background .15s;
}
.aiqs-acc-head:hover { background: var(--aiqs-surface); }
.aiqs-acc-head i.fa-chevron-down { transition: transform .2s; color: var(--aiqs-text-muted); }
.aiqs-accordion.is-open .aiqs-acc-head i.fa-chevron-down { transform: rotate(180deg); }
.aiqs-acc-body { padding: 16px 18px; display: none; background: var(--aiqs-bg); }
.aiqs-accordion.is-open .aiqs-acc-body { display: block; }
.aiqs-acc-body ul, .aiqs-acc-body ol { padding-left: 22px; margin: 8px 0; }
.aiqs-acc-body li { margin-bottom: 8px; line-height: 1.65; }
.aiqs-acc-body p { margin: 8px 0; }
.aiqs-acc-body code { background: var(--aiqs-surface-2); padding: 2px 6px; border-radius: 6px; }
.aiqs-final-answer {
    background: linear-gradient(135deg, rgba(124,58,237,.08), rgba(37,99,235,.08));
    border: 2px solid var(--aiqs-primary); border-radius: 12px;
    padding: 14px 18px; margin-top: 12px; font-size: 16px; font-weight: 600;
}
.aiqs-final-answer strong { color: var(--aiqs-primary); }

.aiqs-meta-row {
    display: flex; gap: 12px; flex-wrap: wrap; margin-top: 8px;
    padding: 12px; background: var(--aiqs-surface-2); border-radius: 10px;
}
.aiqs-meta-row span { font-size: 13px; color: var(--aiqs-text-muted); }
.aiqs-meta-row strong { color: var(--aiqs-text); margin-left: 4px; }

/* ---- Skeleton / loader ---- */
.aiqs-loading {
    display: flex; align-items: center; gap: 12px; padding: 18px;
    color: var(--aiqs-text-muted); font-size: 14px;
}
.aiqs-spinner {
    width: 20px; height: 20px; border-radius: 50%;
    border: 2px solid var(--aiqs-border); border-top-color: var(--aiqs-primary);
    animation: aiqs-spin .8s linear infinite;
}
@keyframes aiqs-spin { to { transform: rotate(360deg); } }

/* ---- Practice quiz ---- */
.aiqs-practice-q { border: 1px solid var(--aiqs-border); border-radius: 12px; padding: 14px; margin-top: 12px; background: var(--aiqs-surface); }
.aiqs-practice-q .aiqs-options { margin-top: 10px; }
.aiqs-practice-q .aiqs-result { margin-top: 10px; font-size: 14px; font-weight: 600; }
.aiqs-practice-q .aiqs-result.is-correct { color: var(--aiqs-success); }
.aiqs-practice-q .aiqs-result.is-wrong   { color: var(--aiqs-danger); }

/* ---- Dashboard ---- */
.aiqs-hero {
    display: flex; justify-content: space-between; align-items: center; gap: 16px;
    padding: 24px; border-radius: var(--aiqs-radius-lg);
    background: linear-gradient(135deg, rgba(124,58,237,.10), rgba(37,99,235,.10));
    border: 1px solid var(--aiqs-border); margin-bottom: 16px; flex-wrap: wrap;
}
.aiqs-hero h2 { margin: 0; font-size: 24px; }
.aiqs-hero-sub { margin: 6px 0 0; color: var(--aiqs-text-muted); }
.aiqs-wave { display: inline-block; animation: aiqs-wave 1.6s ease-in-out infinite; transform-origin: 70% 70%; }
@keyframes aiqs-wave { 0%,60%,100% { transform: rotate(0); } 15% { transform: rotate(14deg); } 30% { transform: rotate(-8deg); } 45% { transform: rotate(10deg); } }

.aiqs-stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; }
.aiqs-stat-card {
    display: flex; align-items: center; gap: 12px;
    padding: 16px; background: var(--aiqs-surface);
    border: 1px solid var(--aiqs-border); border-radius: var(--aiqs-radius);
}
.aiqs-stat-icon {
    width: 44px; height: 44px; border-radius: 12px;
    display: inline-flex; align-items: center; justify-content: center; font-size: 18px;
    flex-shrink: 0;
}
.aiqs-stat-card > div:last-child { display: flex; flex-direction: column; gap: 2px; }
.aiqs-stat-label { color: var(--aiqs-text-muted); font-size: 12px; text-transform: uppercase; letter-spacing: .04em; }
.aiqs-stat-value { font-size: 24px; font-weight: 700; color: var(--aiqs-text); }

.aiqs-section-h { margin: 22px 0 12px; font-size: 18px; color: var(--aiqs-text); display: flex; align-items: center; gap: 8px; }

.aiqs-recent { display: grid; gap: 8px; }
.aiqs-recent-item {
    display: flex; align-items: center; gap: 12px;
    padding: 12px 14px; background: var(--aiqs-surface);
    border: 1px solid var(--aiqs-border); border-radius: 10px;
}
.aiqs-recent-item i { color: var(--aiqs-primary); }
.aiqs-recent-item span { flex: 1; }
.aiqs-recent-item small { color: var(--aiqs-text-muted); }

/* ---- Solver / OCR ---- */
.aiqs-solver-card {
    padding: 22px; background: var(--aiqs-surface);
    border: 1px solid var(--aiqs-border); border-radius: var(--aiqs-radius-lg);
}
.aiqs-solver-card h3 { margin: 0 0 6px; }
.aiqs-muted { color: var(--aiqs-text-muted); margin: 0 0 14px; }
.aiqs-solver-tabs { display: flex; gap: 6px; margin-bottom: 12px; }
.aiqs-tab {
    flex: 1; padding: 10px 14px; border-radius: 10px;
    background: var(--aiqs-bg); border: 1px solid var(--aiqs-border); color: var(--aiqs-text);
    cursor: pointer; font-weight: 600;
}
.aiqs-tab.is-active { background: var(--aiqs-primary); color: #fff; border-color: var(--aiqs-primary); }
.aiqs-solver-text, .aiqs-ocr-text textarea {
    width: 100%; padding: 12px; border-radius: 10px;
    border: 1px solid var(--aiqs-border); background: var(--aiqs-bg); color: var(--aiqs-text);
    font-family: inherit; font-size: 15px; resize: vertical;
}
.aiqs-drop {
    border: 2px dashed var(--aiqs-border); border-radius: 12px;
    padding: 30px; text-align: center; cursor: pointer; color: var(--aiqs-text-muted);
    transition: border-color .15s, background .15s;
}
.aiqs-drop:hover, .aiqs-drop.is-drag { border-color: var(--aiqs-primary); background: rgba(37,99,235,.04); }
.aiqs-drop i { font-size: 32px; display: block; margin-bottom: 10px; color: var(--aiqs-primary); }
.aiqs-drop input { display: none; }
.aiqs-drop-preview img { max-width: 240px; border-radius: 12px; margin-top: 12px; }
.aiqs-ocr-text { margin-top: 12px; }
.aiqs-solver-controls { display: flex; justify-content: flex-end; align-items: center; gap: 10px; margin-top: 14px; }

/* ---- Misc ---- */
.aiqs-empty { padding: 28px; text-align: center; color: var(--aiqs-text-muted); background: var(--aiqs-surface); border: 1px dashed var(--aiqs-border); border-radius: var(--aiqs-radius); }
.aiqs-login-required { padding: 28px; text-align: center; background: var(--aiqs-surface); border: 1px solid var(--aiqs-border); border-radius: var(--aiqs-radius); }
.aiqs-login-required p { color: var(--aiqs-text-muted); margin-bottom: 14px; }

/* ---- Toast ---- */
.aiqs-toast {
    position: fixed; top: 24px; right: 24px; z-index: 999999;
    padding: 12px 18px; background: var(--aiqs-text); color: #fff;
    border-radius: 10px; box-shadow: 0 10px 30px -10px rgba(0,0,0,.3);
    animation: aiqs-toast-in .25s ease-out;
    max-width: 360px;
}
.aiqs-toast.is-error { background: var(--aiqs-danger); }
.aiqs-toast.is-success { background: var(--aiqs-success); }
@keyframes aiqs-toast-in { from { opacity: 0; transform: translateY(-10px); } to { opacity: 1; transform: translateY(0); } }

/* ---- Modal ---- */
.aiqs-modal {
    position: fixed; inset: 0; background: rgba(15,23,42,.5);
    display: flex; align-items: center; justify-content: center; z-index: 999998;
    animation: aiqs-toast-in .2s ease-out;
}
.aiqs-modal-card {
    background: var(--aiqs-bg); border-radius: var(--aiqs-radius-lg);
    padding: 24px; width: 100%; max-width: 420px;
    border: 1px solid var(--aiqs-border);
}
.aiqs-modal-card h3 { margin-top: 0; }
.aiqs-modal-card textarea, .aiqs-modal-card select {
    width: 100%; padding: 10px 12px; border: 1px solid var(--aiqs-border);
    border-radius: 10px; background: var(--aiqs-surface); color: var(--aiqs-text); font-family: inherit;
}
.aiqs-modal-actions { display: flex; gap: 8px; justify-content: flex-end; margin-top: 14px; }