/* ═══════════════════════════════════════════
   Knowledge Center — Public Module Styles
   ═══════════════════════════════════════════ */

.knowledge-center-app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--surface-primary, #faf9f7);
}

/* ── Header ── */
.kc-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: #fff;
    border-bottom: 1px solid var(--border, #e8e4df);
    padding: 0 24px;
}
.kc-header-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 16px;
    height: 60px;
}
.kc-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    flex-shrink: 0;
}
.kc-logo-text {
    font-weight: 800;
    font-size: 18px;
    color: var(--text-primary, #1a1a1a);
}
.kc-header-title {
    flex: 1;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-secondary, #6b6560);
    margin: 0;
}
.kc-join-btn {
    flex-shrink: 0;
}

/* ── Main ── */
.kc-main {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 32px 24px;
    width: 100%;
    box-sizing: border-box;
}

/* ── Section ── */
.kc-section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 24px;
}
.kc-section-header h2 {
    margin: 0;
    font-size: 22px;
    font-weight: 700;
}

/* ── Filters ── */
.kc-filters {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}
.kc-filter-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 6px 14px;
    border-radius: 20px;
    border: 1px solid var(--border, #e8e4df);
    background: #fff;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    color: var(--text-secondary, #6b6560);
    transition: all 0.15s;
}
.kc-filter-btn:hover {
    border-color: var(--primary, #D98D64);
    color: var(--primary, #D98D64);
}
.kc-filter-btn.active {
    background: var(--primary, #D98D64);
    color: #fff;
    border-color: var(--primary, #D98D64);
}

/* ── Class Grid ── */
.kc-class-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}
.kc-class-card {
    background: #fff;
    border: 1px solid var(--border, #e8e4df);
    border-radius: 12px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    transition: box-shadow 0.2s, border-color 0.2s;
}
.kc-class-card:hover {
    border-color: var(--primary, #D98D64);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}
.kc-card-type {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--primary, #D98D64);
}
.kc-card-type .material-symbols-outlined { font-size: 18px; }
.kc-card-title {
    margin: 0;
    font-size: 17px;
    font-weight: 700;
    color: var(--text-primary, #1a1a1a);
    line-height: 1.3;
}
.kc-card-desc {
    margin: 0;
    font-size: 13px;
    color: var(--text-secondary, #6b6560);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.kc-card-meta {
    display: flex;
    align-items: center;
    gap: 16px;
    font-size: 12px;
    color: var(--text-tertiary, #a09a93);
}
.kc-card-meta span {
    display: inline-flex;
    align-items: center;
    gap: 3px;
}
.kc-card-join {
    align-self: flex-start;
}

/* ── Join Modal ── */
.kc-modal-backdrop {
    position: fixed;
    inset: 0;
    z-index: 1000;
    background: rgba(0, 0, 0, 0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}
.kc-modal {
    background: #fff;
    border-radius: 16px;
    max-width: 400px;
    width: 100%;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}
.kc-modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border, #e8e4df);
}
.kc-modal-header h3 { margin: 0; font-size: 17px; font-weight: 700; }
.kc-modal-close {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-tertiary, #a09a93);
    line-height: 1;
}
.kc-modal-body {
    padding: 20px;
}
.kc-modal-footer {
    padding: 12px 20px 20px;
}

/* ── Error ── */
.kc-error {
    background: var(--red-50, #fef2f2);
    color: var(--error, #e53e3e);
    padding: 10px 14px;
    border-radius: 8px;
    font-size: 13px;
    margin-top: 8px;
}

/* ── Loading / Empty ── */
.kc-loading, .kc-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-tertiary, #a09a93);
}
.kc-loading p, .kc-empty p { margin-top: 8px; }

/* ── Viewer ── */
.kc-viewer-header {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 24px;
}
.kc-viewer-info h2 { margin: 0 0 4px; font-size: 22px; }
.kc-viewer-info p { margin: 0; color: var(--text-secondary, #6b6560); font-size: 14px; }

/* ── Exam ── */
.kc-exam {
    max-width: 640px;
    margin: 0 auto;
}
.kc-exam-progress {
    height: 6px;
    background: var(--border, #e8e4df);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 12px;
}
.kc-exam-progress-bar {
    height: 100%;
    background: var(--primary, #D98D64);
    border-radius: 3px;
    transition: width 0.3s;
}
.kc-exam-counter {
    font-size: 13px;
    color: var(--text-tertiary, #a09a93);
    margin-bottom: 16px;
}
.kc-exam-question {
    font-size: 18px;
    font-weight: 600;
    margin: 0 0 20px;
}
.kc-exam-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 24px;
}
.kc-exam-option {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 16px;
    border: 2px solid var(--border, #e8e4df);
    border-radius: 10px;
    cursor: pointer;
    font-size: 15px;
    transition: border-color 0.15s, background 0.15s;
}
.kc-exam-option:hover {
    border-color: var(--primary, #D98D64);
    background: var(--orange-50, #fef8f4);
}
.kc-exam-option.selected {
    border-color: var(--primary, #D98D64);
    background: var(--orange-100, #fdeee3);
}
.kc-exam-option input[type="radio"] { accent-color: var(--primary, #D98D64); }
.kc-exam-nav {
    display: flex;
    justify-content: space-between;
    gap: 12px;
}

/* ── Score Card ── */
.kc-score-card {
    text-align: center;
    padding: 40px 20px;
    max-width: 400px;
    margin: 0 auto;
}
.kc-score-circle {
    position: relative;
    display: inline-block;
    margin-bottom: 20px;
}
.kc-score-pct {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: 800;
    color: var(--text-primary, #1a1a1a);
}
.kc-score-card h3 { margin: 0 0 8px; font-size: 20px; }
.kc-score-card p { color: var(--text-secondary, #6b6560); margin: 0 0 20px; }

/* ── Video ── */
.kc-video-list {
    display: flex;
    flex-direction: column;
    gap: 24px;
}
.kc-video-item {
    background: #fff;
    border: 1px solid var(--border, #e8e4df);
    border-radius: 12px;
    padding: 20px;
}
.kc-video-item h3 { margin: 0 0 12px; font-size: 16px; font-weight: 600; }
.kc-video-embed {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    border-radius: 8px;
    margin-bottom: 12px;
}
.kc-video-embed iframe {
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
}
.kc-resource-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--primary, #D98D64);
    text-decoration: none;
    font-weight: 500;
}
.kc-resource-link:hover { text-decoration: underline; }
.kc-video-desc {
    margin: 8px 0 0;
    font-size: 14px;
    color: var(--text-secondary, #6b6560);
}

/* ── Poll ── */
.kc-poll-list {
    max-width: 640px;
    margin: 0 auto;
}
.kc-poll-card {
    background: #fff;
    border: 1px solid var(--border, #e8e4df);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 16px;
}
.kc-poll-card h3 { margin: 0 0 14px; font-size: 16px; font-weight: 600; }
.kc-poll-options {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.kc-poll-option {
    display: block;
    width: 100%;
    text-align: left;
    padding: 12px 16px;
    border: 2px solid var(--border, #e8e4df);
    border-radius: 8px;
    background: #fff;
    font-size: 14px;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s;
}
.kc-poll-option:hover {
    border-color: var(--primary, #D98D64);
}
.kc-poll-option.selected {
    border-color: var(--primary, #D98D64);
    background: var(--orange-100, #fdeee3);
    font-weight: 600;
}

/* ── Footer ── */
.kc-footer {
    text-align: center;
    padding: 24px;
    color: var(--text-tertiary, #a09a93);
    font-size: 13px;
    border-top: 1px solid var(--border, #e8e4df);
}

/* ── Responsive ── */
@media (max-width: 640px) {
    .kc-header-inner { padding: 0; }
    .kc-header-title { display: none; }
    .kc-class-grid { grid-template-columns: 1fr; }
    .kc-section-header { flex-direction: column; align-items: flex-start; }
}