* {
    box-sizing: border-box;
}

:root {
    --primary: #3b82f6;
    --secondary: #10b981;
    --accent: #f59e0b;
    --bg: #f1f5f9;
    --card-bg: #ffffff;
    --text: #1e293b;
    --border: #e2e8f0;
    --inner-box-bg: #f9f9f9;
}

/* 다크 모드 변수 정의 */
body.dark-mode {
    --bg: #0f172a;
    --card-bg: #1e293b;
    --text: #f1f5f9;
    --border: #334155;
    --inner-box-bg: #2d3748;
}

body {
    font-family: 'Pretendard', sans-serif;
    background: var(--bg);
    padding: 15px;
    margin: 0;
    color: var(--text);
    transition: background 0.3s, color 0.3s;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

/* 필터 패널 스타일 */
.filter-panel {
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
    position: sticky;
    top: 10px;
    z-index: 100;
    overflow: visible;
    border: 1px solid var(--border);
}

.filter-header {
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    background: var(--card-bg);
    user-select: none;
    border-radius: 16px 16px 0 0;
}

.filter-header h2 {
    margin: 0;
    font-size: 1.1em;
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-summary {
    font-size: 0.85em;
    color: var(--primary);
    font-weight: bold;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 10px;
}

.mode-menu-wrap {
    position: relative;
}

.feature-bubble {
    position: absolute;
    right: 42px;
    top: -8px;
    background: #0ea5e9;
    color: white;
    font-size: 12px;
    padding: 6px 10px;
    border-radius: 999px;
    white-space: nowrap;
    box-shadow: 0 6px 16px rgba(14, 165, 233, 0.35);
    display: none;
    cursor: pointer;
    z-index: 320;
}

.feature-bubble::after {
    content: "";
    position: absolute;
    right: -6px;
    top: 50%;
    transform: translateY(-50%);
    border-width: 6px 0 6px 6px;
    border-style: solid;
    border-color: transparent transparent transparent #0ea5e9;
}

.menu-btn {
    width: 34px;
    height: 34px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg);
    color: var(--text);
    cursor: pointer;
    font-size: 16px;
    line-height: 1;
}

.mode-menu {
    position: absolute;
    right: 0;
    top: 40px;
    min-width: 150px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
    padding: 6px;
    display: none;
    z-index: 300;
}

.mode-menu button {
    width: 100%;
    text-align: left;
    border: none;
    background: transparent;
    color: var(--text);
    padding: 8px 10px;
    border-radius: 8px;
    cursor: pointer;
}

.mode-menu button.active {
    background: var(--bg);
    font-weight: bold;
}

.filter-content {
    padding: 0 20px 20px 20px;
    max-height: 500px;
    transition: max-height 0.3s ease-in-out, padding 0.3s ease-in-out, opacity 0.2s ease-in-out;
    opacity: 1;
    overflow: hidden;
}

.filter-panel.collapsed .filter-content {
    max-height: 0;
    padding-top: 0;
    padding-bottom: 0;
    opacity: 0;
    pointer-events: none;
}

.filter-panel.collapsed .filter-header {
    border-radius: 16px;
}

.filter-row {
    margin-top: 15px;
}

.label {
    font-weight: bold;
    display: block;
    margin-bottom: 8px;
    color: #64748b;
    font-size: 0.85em;
}

.tag-group {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.tag {
    padding: 6px 12px;
    background: var(--bg);
    border-radius: 50px;
    cursor: pointer;
    font-size: 0.8em;
    border: 1px solid var(--border);
    transition: 0.2s;
    color: var(--text);
}

.tag.active.session {
    background: var(--secondary);
    color: white;
    border-color: var(--secondary);
}

.tag.active.subject {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.tag.active.subsubject {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

#searchInput {
    width: 100%;
    padding: 12px;
    border-radius: 8px;
    border: 1px solid var(--border);
    font-size: 0.95em;
    outline: none;
    background: var(--card-bg);
    color: var(--text);
}

/* 문제 카드 */
.q-card {
    content-visibility: auto;
    background: var(--card-bg);
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 15px;
    border: 1px solid var(--border);
}

.q-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

.q-action-buttons {
    display: flex;
    align-items: center;
    gap: 6px;
}

.memo-icon-btn {
    width: 32px;
    height: 32px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: transparent;
    color: var(--text);
    cursor: pointer;
    font-size: 16px;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    filter: grayscale(1);
    opacity: 0.75;
    flex-shrink: 0;
}

.memo-icon-btn:hover {
    border-color: var(--primary);
}

.memo-icon-btn.active {
    filter: grayscale(0);
    opacity: 1;
}

.favorite-icon-btn {
    width: 32px;
    height: 32px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: transparent;
    color: #eab308;
    cursor: pointer;
    font-size: 16px;
    line-height: 1;
    filter: grayscale(1);
    opacity: 0.75;
    flex-shrink: 0;
}

.favorite-icon-btn.active {
    filter: grayscale(0);
    opacity: 1;
}

.favorite-icon-btn:hover {
    border-color: var(--primary);
}

.memo-editor {
    margin-top: 10px;
    margin-bottom: 10px;
}

.memo-textarea {
    width: 100%;
    min-height: 84px;
    resize: vertical;
    padding: 10px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 0.9em;
    background: var(--card-bg);
    color: var(--text);
    outline: none;
}

.btn-ans {
    width: 100%;
    margin-top: 15px;
    padding: 12px;
    cursor: pointer;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    font-weight: bold;
    color: var(--text);
}

.ans-section {
    display: none;
    margin-top: 10px;
    padding: 15px;
    background: #f0fdf4;
    border-radius: 8px;
    border-left: 4px solid #22c55e;
}

body.dark-mode .ans-section {
    background: #064e3b;
    border-color: #10b981;
}

body.dark-mode .ans-section div {
    color: #d1fae5 !important;
}

.memo-preview {
    margin-top: 12px;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid rgba(34, 197, 94, 0.35);
    background: rgba(34, 197, 94, 0.08);
    color: var(--text);
    font-size: 0.92em;
    line-height: 1.6;
}

.memo-preview-title {
    font-weight: bold;
    margin-bottom: 5px;
}

.arrow {
    transition: transform 0.3s;
}

.collapsed .arrow {
    transform: rotate(-180deg);
}

.inner-box {
    background-color: var(--inner-box-bg);
    border: 1px dashed #555;
    padding: 15px;
    margin: 15px 0;
    font-size: 0.95em;
    line-height: 1.8;
    border-radius: 6px;
    color: var(--text);
    width: 100%;
    box-sizing: border-box;
    word-break: break-all;
}

/* TOP 버튼 */
#btnTop {
    position: fixed;
    bottom: 30px;
    right: 20px;
    z-index: 99;
    background: var(--primary);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    font-weight: bold;
}

.quiz-table {
    width: 100%;
    border-collapse: collapse;
    margin: 15px 0;
    font-size: 14px;
}

.quiz-table th,
.quiz-table td {
    border: 1px solid var(--border);
    padding: 6px 2px;
    text-align: center;
}

.quiz-table th {
    background-color: var(--inner-box-bg);
    font-weight: bold;
}

.mock-panel {
    margin-top: 18px;
    padding: 14px;
    border: 1px solid var(--border);
    border-radius: 10px;
    background: var(--bg);
}

.mock-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
    margin-top: 10px;
}

.mock-number-input {
    width: 90px;
    padding: 8px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--card-bg);
    color: var(--text);
}

.mock-btn {
    padding: 8px 14px;
    border: none;
    border-radius: 8px;
    color: white;
    cursor: pointer;
    font-weight: bold;
}

.mock-btn.start {
    background: #0ea5e9;
}

.mock-btn.end {
    background: #ef4444;
}

.mock-btn.pause {
    background: #f59e0b;
}

.mock-timer {
    margin-top: 10px;
    font-weight: bold;
    color: var(--accent);
}

.mock-option.selected {
    border-color: var(--primary) !important;
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.mock-option.correct {
    border-color: #16a34a !important;
    background: rgba(34, 197, 94, 0.15) !important;
}

.mock-option.wrong {
    border-color: #dc2626 !important;
    background: rgba(239, 68, 68, 0.15) !important;
}

mark {
    border-radius: 3px;
    color: black;
}

/* 다크모드/도움말 모달 내부 텍스트 수정 */
body.dark-mode #helpModal>div {
    background: var(--card-bg);
    color: var(--text);
}

/* 토글 스위치 디자인 */
.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 26px;
    vertical-align: middle;
}

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

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked+.slider {
    background-color: var(--primary);
}

input:checked+.slider:before {
    transform: translateX(24px);
}

/* 다크모드 시 토글 내부 아이콘 처리 (선택사항) */
.slider-icon {
    position: absolute;
    top: 4px;
    font-size: 12px;
    pointer-events: none;
    transition: .4s;
}

.sun {
    right: 6px;
    color: #f59e0b;
}

.moon {
    left: 8px;
    color: #f1f5f9;
    opacity: 0;
}

input:checked~.sun {
    opacity: 0;
}

input:checked~.moon {
    opacity: 1;
}