/* 색상 변수 */
:root {
    --color-bg-page: #f3f4f6;
    --color-paper: #ffffff;
    --color-ink: #222222;
    --color-muted: #6b7280;
    --color-border: #e5e7eb;
    --color-accent: #f97373;      /* 코랄 계열 포인트 */
    --color-accent-soft: #fde2e2; /* 연한 강조 배경 */
}

/* 기본 스타일 */
*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans KR', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.7;
    margin: 0;
    padding: 0;
    background-color: var(--color-bg-page);
    color: var(--color-ink);
}

/* 헤더 */
.site-header {
    background-color: #111827;
    color: #f9fafb;
    padding: 18px 16px;
    border-bottom: 3px solid var(--color-accent);
}

.header-inner {
    max-width: 960px;
    margin: 0 auto;
}

.site-header h1 {
    margin: 0;
    font-weight: 700;
    font-size: 1.5rem;
}

.header-subtitle {
    margin: 6px 0 0;
    font-size: 0.95rem;
    color: #e5e7eb;
}

/* 메인 카드 컨테이너 */
.note-page {
    max-width: 960px;
    margin: 32px auto;
    padding: 32px 28px 40px;
    background-color: var(--color-paper);
    border-radius: 14px;
    box-shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
}

/* 탭 메뉴 */
.tab-menu {
    display: flex;
    gap: 8px;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 6px;
    margin-bottom: 24px;
}

.tab-button {
    background-color: transparent;
    border: none;
    padding: 10px 16px;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--color-muted);
    cursor: pointer;
    border-radius: 10px 10px 0 0;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.tab-button:hover {
    color: var(--color-ink);
    background-color: #f3f4f6;
}

.tab-button.active {
    color: #111827;
    background-color: var(--color-paper);
    border-bottom: 2px solid var(--color-accent);
}

/* 섹션 */
.concept-section {
    display: none;
    padding-top: 8px;
}

.concept-section.active {
    display: block;
}

.concept-section h2 {
    font-size: 1.5rem;
    margin: 4px 0 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--color-border);
}

.note-content h3 {
    font-size: 1.05rem;
    margin-top: 24px;
    margin-bottom: 8px;
    padding-left: 10px;
    border-left: 3px solid var(--color-accent);
}

/* 강조 문장 */
.highlight {
    background-color: var(--color-accent-soft);
    border-radius: 6px;
    padding: 10px 12px;
    margin-bottom: 16px;
    font-size: 0.95rem;
}

/* 리스트 스타일 */
.note-content ul {
    list-style: none;
    padding-left: 0;
    margin: 0 0 8px;
}

.note-content ul li {
    position: relative;
    padding-left: 16px;
    margin-bottom: 6px;
    font-size: 0.95rem;
}

.note-content ul li::before {
    content: "•";
    position: absolute;
    left: 0;
    top: 0;
    line-height: 1.5;
    font-size: 0.85rem;
    color: var(--color-accent);
}

/* 인라인 코드 & 코드 블록 */
code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.88em;
    padding: 2px 4px;
    border-radius: 3px;
    background-color: #f3f4f6;
    border: 1px solid #e5e7eb;
}

pre {
    margin: 14px 0;
    padding: 14px 16px;
    border-radius: 10px;
    background-color: #f9fafb;
    border: 1px solid var(--color-border);
    overflow-x: auto;
    font-size: 0.88rem;
}

pre code {
    border: none;
    background: transparent;
    padding: 0;
}

/* 테이블 */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 16px 0;
    font-size: 0.9rem;
}

table th,
table td {
    padding: 10px 8px;
    border: 1px solid var(--color-border);
    text-align: left;
    vertical-align: top;
}

table th {
    background-color: #f9fafb;
    font-weight: 600;
}

table td code {
    white-space: nowrap;
}

/* 푸터 */
.site-footer {
    max-width: 960px;
    margin: 0 auto 24px;
    padding: 8px 4px 0;
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-muted);
    border-top: 1px solid rgba(148, 163, 184, 0.4);
}