/* ============================= */
/* V3 해설 보기 화면 (Split)      */
/* ============================= */

/* 헤더 */
.explain-viewer-header {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 24px;
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

.btn-back-to-dashboard {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    padding: 6px 10px;
    border-radius: 8px;
    transition: all 0.2s;
    font-family: inherit;
    white-space: nowrap;
}

.btn-back-to-dashboard:hover {
    background: var(--bg-color);
    color: var(--text-primary);
}

.explain-viewer-title-area {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 18px;
    font-weight: 700;
    color: var(--text-primary);
}

.explain-viewer-subtitle {
    font-size: 13px;
    font-weight: 400;
    color: var(--text-secondary);
}

/* 메인 레이아웃: 좌우 split */
.explain-viewer-body {
    display: flex;
    height: calc(100vh - 57px);
    overflow: hidden;
}

/* 좌측: 해설 콘텐츠 */
.explain-viewer-left {
    flex: 0 0 60%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    border-right: 1px solid var(--border-color);
}

/* 우측: 메모장 */
.explain-viewer-right {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* ============================= */
/* 탭 바                          */
/* ============================= */

.explain-tab-bar {
    display: flex;
    gap: 0;
    background: var(--surface-color);
    border-bottom: 2px solid var(--border-color);
    padding: 0 24px;
    flex-shrink: 0;
}

.explain-tab-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 14px 20px;
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
    white-space: nowrap;
}

.explain-tab-btn:hover {
    color: var(--text-primary);
    background: var(--bg-color);
}

.explain-tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.explain-tab-icon {
    font-size: 15px;
}

.explain-tab-score {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-left: 2px;
}

.explain-tab-btn.active .explain-tab-score {
    color: var(--primary-color);
}

/* 탭 콘텐츠 */
.explain-tab-content {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
}

.explain-tab-content:not(.active) {
    display: none;
}

/* ============================= */
/* 메모장 (오답노트)               */
/* ============================= */

.explain-memo-panel {
    display: flex;
    flex-direction: column;
    height: 100%;
    background: var(--surface-color);
}

.explain-memo-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

.explain-memo-title {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-primary);
}

/* 상태 메시지 (잠김/읽기전용) */
.explain-memo-status {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 16px 20px;
    background: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
}

.explain-memo-status i {
    color: var(--text-secondary);
    font-size: 14px;
    margin-top: 2px;
}

.explain-memo-status p {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
    margin: 0;
}

/* 메모 작성 영역 */
.explain-memo-body {
    flex: 1;
    padding: 16px 20px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.explain-memo-textarea {
    width: 100%;
    flex: 1;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 16px;
    font-size: 14px;
    font-family: inherit;
    line-height: 1.7;
    color: var(--text-primary);
    background: var(--bg-color);
    resize: none;
    outline: none;
    transition: border-color 0.2s;
}

.explain-memo-textarea:focus {
    border-color: var(--primary-color);
}

.explain-memo-textarea::placeholder {
    color: var(--text-secondary);
    font-size: 13px;
}

.explain-memo-textarea:disabled {
    background: #f9fafb;
    color: var(--text-secondary);
    cursor: not-allowed;
}

/* 하단 정보 */
.explain-memo-footer {
    padding: 12px 20px 16px;
    border-top: 1px solid var(--border-color);
    flex-shrink: 0;
}

.explain-memo-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.explain-memo-autosave {
    font-size: 12px;
    color: var(--success-color);
    font-weight: 500;
}

.explain-memo-word-count {
    font-size: 12px;
    color: var(--text-secondary);
}

.explain-memo-submit-btn {
    width: 100%;
    padding: 12px;
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

.explain-memo-submit-btn:hover:not(:disabled) {
    background: #7C5CBF;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(148, 128, 197, 0.3);
}

.explain-memo-submit-btn:disabled {
    background: var(--border-color);
    color: var(--text-secondary);
    cursor: not-allowed;
}

/* ============================= */
/* 스피킹 파일 첨부                */
/* ============================= */

.explain-speaking-file-area {
    padding: 16px 20px;
    border-top: 1px solid var(--border-color);
    flex-shrink: 0;
}

.explain-speaking-file-header {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.explain-speaking-file-area input[type="file"] {
    width: 100%;
    font-size: 13px;
    font-family: inherit;
    color: var(--text-primary);
}

.explain-speaking-file-msg {
    font-size: 12px;
    color: var(--text-secondary);
    line-height: 1.5;
    margin: 8px 0 0;
}

/* ============================= */
/* 모바일 대응                     */
/* ============================= */

@media (max-width: 768px) {
    .explain-viewer-body {
        flex-direction: column;
        height: auto;
        overflow: visible;
    }

    .explain-viewer-left {
        flex: none;
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        min-height: 50vh;
    }

    .explain-viewer-right {
        width: 100%;
        min-height: 40vh;
    }

    .explain-tab-bar {
        padding: 0 16px;
    }

    .explain-tab-content {
        padding: 16px;
    }

    .explain-memo-body {
        padding: 12px 16px;
    }

    .explain-memo-textarea {
        min-height: 200px;
    }
}