/* 考研数学公式大全 - 响应式 + 深色/浅色主题 */
:root {
    --primary: #1a5f7a;
    --primary-light: #2d8aad;
    --accent: #159895;
    --bg: #f5f7fa;
    --card-bg: #ffffff;
    --text: #2c3e50;
    --text-muted: #6c757d;
    --shadow: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
    --radius: 12px;
    --radius-sm: 8px;
    /* 改动1: 模态框公式字体 - 桌面端 24px */
    --modal-formula-size: 24px;
    --formula-preview-size: 0.9rem;
}

/* 改动2: 深色主题 */
html.dark {
    --bg: #1a1d23;
    --card-bg: #252a32;
    --text: #e4e6eb;
    --text-muted: #b0b3b8;
    --shadow: 0 4px 12px rgba(0,0,0,0.3);
    --shadow-hover: 0 8px 24px rgba(0,0,0,0.4);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.app-shell {
    min-height: 100vh;
}

body.auth-lock {
    overflow: hidden;
}

body.auth-lock .app-shell {
    filter: blur(4px);
    transform: translateZ(0);
}

/* 改动3: 头部布局（含主题按钮） */
.header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    padding: 2rem 1.5rem;
    text-align: center;
    box-shadow: var(--shadow);
    position: relative;
}

.header-inner { position: relative; }

.theme-toggle {
    position: absolute;
    top: 0.5rem;
    right: 1rem;
    width: 40px;
    height: 40px;
    border: none;
    background: rgba(255,255,255,0.2);
    border-radius: 50%;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background 0.2s;
}

.theme-toggle:hover {
    background: rgba(255,255,255,0.35);
}

.header h1 {
    font-size: clamp(1.5rem, 4vw, 2rem);
    font-weight: 700;
    letter-spacing: 0.05em;
}

.subtitle {
    margin-top: 0.5rem;
    font-size: 0.95rem;
    opacity: 0.9;
}

.main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.5rem;
}

.controls {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.controls-top {
    display: flex;
    justify-content: flex-start;
}

.manual-open-btn {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    border-radius: var(--radius-sm);
    border: none;
    background: var(--primary);
    color: #fff;
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: background 0.2s, transform 0.2s;
}

.manual-open-btn:hover {
    background: var(--primary-light);
    transform: translateY(-1px);
}

.search-box {
    position: relative;
    max-width: 400px;
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.5rem;
    font-size: 1rem;
    border: 2px solid rgba(0,0,0,0.1);
    border-radius: var(--radius-sm);
    background: var(--card-bg);
    color: var(--text);
    transition: border-color 0.2s, box-shadow 0.2s;
}

html.dark .search-box input {
    border-color: rgba(255,255,255,0.15);
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26, 95, 122, 0.15);
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.1rem;
    opacity: 0.6;
}

.filter-btns {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.filter-btn {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    border: 2px solid rgba(0,0,0,0.1);
    background: var(--card-bg);
    color: var(--text);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s;
}

html.dark .filter-btn {
    border-color: rgba(255,255,255,0.15);
}

.filter-btn:hover {
    border-color: var(--primary-light);
    color: var(--primary);
}

.filter-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

/* 改动4: 收藏筛选 */
.favorites-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-muted);
    cursor: pointer;
}

.favorites-toggle input { cursor: pointer; }

.subject-btns {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
}

.subject-label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.subject-btn {
    padding: 0.35rem 0.75rem;
    font-size: 0.85rem;
    border: 1px solid rgba(0,0,0,0.12);
    background: var(--card-bg);
    color: var(--text);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s;
}

html.dark .subject-btn {
    border-color: rgba(255,255,255,0.2);
}

.subject-btn:hover {
    border-color: var(--primary-light);
    color: var(--primary);
}

.subject-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.formula-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.formula-card {
    position: relative;
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.25rem;
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    border: 1px solid rgba(0,0,0,0.05);
}

.formula-category-tag {
    position: absolute;
    bottom: 0.5rem;
    right: 0.5rem;
    font-size: 0.75rem;
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-weight: 500;
}

.formula-category-tag--gaoshu {
    background: rgba(26, 95, 122, 0.15);
    color: #1a5f7a;
}

html.dark .formula-category-tag--gaoshu {
    background: rgba(45, 138, 173, 0.25);
    color: #5eb8d4;
}

.formula-category-tag--xiandai {
    background: rgba(155, 89, 182, 0.15);
    color: #6c3483;
}

html.dark .formula-category-tag--xiandai {
    background: rgba(155, 89, 182, 0.3);
    color: #bb8fce;
}

.formula-category-tag--gailv {
    background: rgba(211, 84, 0, 0.15);
    color: #c0392b;
}

html.dark .formula-category-tag--gailv {
    background: rgba(211, 84, 0, 0.3);
    color: #e59866;
}

html.dark .formula-card {
    border-color: rgba(255,255,255,0.08);
}

.formula-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

.formula-card.favored {
    border-color: var(--accent);
}

/* 改动5: 卡片公式预览 - KaTeX 或 SVG，自动缩放不溢出 */
.formula-preview {
    width: 100%;
    min-height: 80px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(26,95,122,0.05) 0%, rgba(21,152,149,0.05) 100%);
    border-radius: var(--radius-sm);
    padding: 0.75rem;
    margin-bottom: 1rem;
    text-align: center;
    overflow: hidden;
}

.formula-preview .formula-katex {
    font-size: var(--formula-preview-size);
    max-width: 100%;
    overflow-x: auto;
}

.formula-preview .formula-katex .katex {
    font-size: inherit;
}

.formula-preview-svg {
    width: 100%;
    max-height: 70px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.formula-preview-svg svg {
    max-width: 100%;
    max-height: 65px;
    width: auto;
    height: auto;
    color: var(--text);
}

.formula-zoom-hint {
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-top: 0.3rem;
}

.formula-subjects {
    font-size: 0.8rem;
    color: var(--accent);
    margin-bottom: 0.25rem;
}

.formula-preview-text {
    font-size: var(--formula-preview-size);
    color: var(--text);
    white-space: pre-wrap;
    word-break: break-all;
}

.formula-name {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 0.35rem;
}

.formula-chapter {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.formula-grid:empty::after {
    content: "暂无匹配公式";
    grid-column: 1 / -1;
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
}

/* 改动6: 模态框 - 公式区响应式字体、支持缩放 */
.modal {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.5);
    cursor: pointer;
}

.modal-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 44px;
    height: 44px;
    border: none;
    background: var(--card-bg);
    color: var(--text);
    font-size: 1.8rem;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--shadow);
    z-index: 1002;
    line-height: 1;
    padding-bottom: 4px;
}

.modal-nav-prev { left: 0.5rem; }
.modal-nav-next { right: 0.5rem; }

.modal-nav:hover {
    background: var(--primary);
    color: white;
}

.modal-content {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem;
    max-width: 720px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    transform: scale(0.95);
    transition: transform 0.3s;
    z-index: 1001;
}

.modal.active .modal-content {
    transform: scale(1);
}

.modal-toolbar {
    position: absolute;
    top: 1rem;
    right: 1rem;
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.modal-close,
.modal-btn,
.manual-close {
    width: 36px;
    height: 36px;
    border: none;
    background: rgba(0,0,0,0.08);
    font-size: 1.2rem;
    line-height: 1;
    cursor: pointer;
    border-radius: 50%;
    color: var(--text);
    transition: background 0.2s;
}

html.dark .modal-close,
html.dark .modal-btn,
html.dark .manual-close {
    background: rgba(255,255,255,0.1);
}

.modal-close:hover,
.modal-btn:hover {
    background: rgba(0,0,0,0.15);
}

.modal-fav.active {
    color: #e74c3c;
}

.modal-zoom {
    display: flex;
    gap: 2px;
}

.modal-zoom .modal-btn {
    width: 32px;
    height: 32px;
    font-size: 1rem;
}

.modal-title {
    font-size: 1.35rem;
    margin-bottom: 0.5rem;
    padding-right: 8rem;
}

.modal-subject {
    font-size: 0.85rem;
    color: var(--accent);
    margin-bottom: 0.35rem;
}

.modal-chapter {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

.modal-formula-preview-text {
    font-size: var(--modal-formula-size);
    color: var(--text);
    white-space: pre-wrap;
    word-break: break-all;
}

/* 改动7: 模态框公式区 - 桌面 24px，手机 18px，支持 transform 缩放 */
.modal-svg-wrap {
    background: linear-gradient(135deg, rgba(26,95,122,0.06) 0%, rgba(21,152,149,0.06) 100%);
    border-radius: var(--radius-sm);
    padding: 2rem;
    min-height: 160px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: auto;
}

.modal-svg {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-svg svg {
    max-width: 100%;
    max-height: 380px;
    width: auto;
    height: auto;
    /* 桌面端 24px 等效 */
    font-size: var(--modal-formula-size);
}

.modal-formula-katex {
    font-size: var(--modal-formula-size);
    color: var(--text);
}

.modal-formula-katex .katex {
    font-size: inherit;
}

.modal-formula-svg {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-formula-svg svg {
    color: var(--text);
}

.modal-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-align: center;
    margin-top: 1rem;
}

/* 公告栏 */
.announcement-panel {
    position: fixed;
    right: 1rem;
    top: 7rem;
    width: 260px;
    max-width: 40vw;
    background: var(--card-bg);
    box-shadow: var(--shadow);
    border-radius: var(--radius);
    padding: 1rem 1.25rem 1.25rem;
    z-index: 900;
    border: 1px solid rgba(0,0,0,0.06);
}

html.dark .announcement-panel {
    border-color: rgba(255,255,255,0.08);
}

.announcement-title {
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.announcement-text {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.announcement-manual-btn {
    padding: 0.4rem 0.9rem;
    font-size: 0.85rem;
    border-radius: var(--radius-sm);
    border: none;
    background: var(--accent);
    color: #fff;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s;
}

.announcement-manual-btn:hover {
    background: var(--primary);
    transform: translateY(-1px);
}

/* 使用手册模态框 */
.manual-modal {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    z-index: 1500;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}

.manual-modal.active {
    opacity: 1;
    visibility: visible;
}

.manual-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.45);
}

.manual-content {
    position: relative;
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.75rem 2rem;
    max-width: 640px;
    width: 100%;
    box-shadow: 0 16px 48px rgba(0,0,0,0.35);
}

.manual-close {
    position: absolute;
    top: 0.9rem;
    right: 0.9rem;
}

.manual-title {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    padding-right: 2.5rem;
}

.manual-body {
    font-size: 0.95rem;
    color: var(--text);
}

.manual-body ol {
    padding-left: 1.25rem;
}

.manual-body li + li {
    margin-top: 0.35rem;
}

/* 访问密码弹窗 */
.auth-modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s, visibility 0.25s;
}

.auth-modal.active {
    opacity: 1;
    visibility: visible;
}

.auth-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.45);
    backdrop-filter: blur(6px);
}

.auth-dialog {
    position: relative;
    z-index: 2001;
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem 2.5rem 2.25rem;
    max-width: 360px;
    width: 100%;
    box-shadow: 0 18px 56px rgba(0,0,0,0.45);
    text-align: center;
}

.auth-title {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.auth-desc {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

.auth-input {
    width: 100%;
    padding: 0.6rem 0.8rem;
    border-radius: var(--radius-sm);
    border: 2px solid rgba(0,0,0,0.1);
    font-size: 0.95rem;
    outline: none;
}

html.dark .auth-input {
    border-color: rgba(255,255,255,0.18);
    background: var(--card-bg);
    color: var(--text);
}

.auth-input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26,95,122,0.18);
}

.auth-error {
    min-height: 1.1rem;
    font-size: 0.8rem;
    color: #e74c3c;
    margin-top: 0.4rem;
    margin-bottom: 0.6rem;
}

.auth-confirm {
    margin-top: 0.4rem;
    width: 100%;
    padding: 0.6rem 0.8rem;
    border-radius: var(--radius-sm);
    border: none;
    background: var(--primary);
    color: #fff;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s;
}

.auth-confirm:hover {
    background: var(--primary-light);
    transform: translateY(-1px);
}

/* 改动8: 响应式 - 手机端公式最小 18px */
@media (max-width: 768px) {
    :root {
        --modal-formula-size: 18px;
        --formula-preview-size: 0.85rem;
    }

    .header { padding: 1.5rem 1rem; }
    .theme-toggle { right: 0.5rem; top: 0.25rem; }

    .main { padding: 1rem; }

    .announcement-panel {
        position: static;
        width: auto;
        max-width: 100%;
        margin: 0 1rem 1.5rem;
    }

    .formula-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .formula-card { padding: 1rem; }

    .formula-preview { min-height: 72px; }
    .formula-preview-svg svg { max-height: 58px; }

    .modal-content { padding: 1.5rem; }
    .modal-svg-wrap { padding: 1.5rem; min-height: 140px; }
    .modal-svg svg { max-height: 280px; }

    .modal-nav {
        width: 36px;
        height: 36px;
        font-size: 1.5rem;
    }
    .modal-nav-prev { left: 0.25rem; }
    .modal-nav-next { right: 0.25rem; }
}

@media (max-width: 480px) {
    .filter-btns { width: 100%; }
    .filter-btn { flex: 1; min-width: 0; }
    .search-box { max-width: 100%; }
}