/* ── Reset & Base ── */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* Respect user's motion preferences */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

:root {
    /* Design tokens - spacing (8px grid) */
    --space-xs: 0.25rem;  /* 4px */
    --space-sm: 0.5rem;   /* 8px */
    --space-md: 1rem;     /* 16px */
    --space-lg: 1.5rem;   /* 24px */
    --space-xl: 2rem;     /* 32px */
    --space-2xl: 3rem;    /* 48px */

    /* Typography scale */
    --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
    --text-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem);
    --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
    --text-lg: clamp(1.125rem, 1rem + 0.625vw, 1.5rem);
    --text-xl: clamp(1.5rem, 1.25rem + 1.25vw, 2rem);
    --text-2xl: clamp(1.75rem, 1.5rem + 1.25vw, 2.5rem);

    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Courier New', Courier, monospace, sans-serif;
    background-color: #0a0e1a;
    color: #e0e0e0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-image:
        radial-gradient(circle, rgba(255,255,255,0.9) 1px, transparent 1px),
        radial-gradient(circle, rgba(255,255,255,0.7) 1px, transparent 1px),
        radial-gradient(circle, rgba(255,255,255,0.5) 1px, transparent 1px);
    background-size: 150px 150px, 200px 200px, 250px 250px;
    background-position: 0 0, 40px 60px, 130px 270px;
    transition: background-color var(--transition-slow), color var(--transition-slow);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ── Day Mode (all pages) ── */
body.day-mode,
html.day-mode body {
    background-color: #e8f4f8;
    background-image:
        radial-gradient(circle at 30% 20%, rgba(173, 216, 230, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 70% 80%, rgba(135, 206, 235, 0.2) 0%, transparent 50%);
    background-size: 100% 100%;
    background-repeat: no-repeat;
    background-attachment: fixed;
    color: #1a1a1a;
}

/* ── Theme Toggle Button ── */
.theme-toggle {
    position: fixed;
    top: var(--space-xl);
    right: var(--space-xl);
    z-index: 1000;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: #fff;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-full);
    cursor: pointer;
    font-family: inherit;
    font-weight: 600;
    font-size: var(--text-sm);
    backdrop-filter: blur(10px);
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    box-shadow: var(--shadow-md);
    min-width: 44px;
    min-height: 44px;
    justify-content: center;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.theme-toggle:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: 2px;
}

.theme-toggle:active {
    transform: translateY(0);
}

.day-mode .theme-toggle {
    background: rgba(0, 0, 0, 0.06);
    border-color: rgba(0, 0, 0, 0.12);
    color: #1a1a1a;
}

.day-mode .theme-toggle:hover {
    background: rgba(0, 0, 0, 0.12);
}

/* ── Mobile menu toggle button ── */
.mobile-menu-toggle {
    display: none;
    position: fixed;
    top: var(--space-lg);
    left: var(--space-lg);
    z-index: 1001;
    background: rgba(26,188,156,0.9);
    border: none;
    color: #fff;
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: var(--text-lg);
    backdrop-filter: blur(10px);
    transition: all var(--transition-base);
    box-shadow: var(--shadow-lg);
    align-items: center;
    justify-content: center;
}

.mobile-menu-toggle:hover {
    background: rgba(26,188,156,1);
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.mobile-menu-toggle:focus-visible {
    outline: 2px solid #fff;
    outline-offset: 2px;
}

.mobile-menu-toggle:active {
    transform: translateY(0);
}

.mobile-menu-toggle.active {
    background: rgba(231,76,60,0.9);
}

.mobile-menu-toggle.active:hover {
    background: rgba(231,76,60,1);
}
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 200px;
    height: 100vh;
    background: rgba(8, 8, 18, 0.92);
    backdrop-filter: blur(12px);
    border-right: 1px solid rgba(255,255,255,0.06);
    z-index: 100;
    display: flex;
    flex-direction: column;
    padding: var(--space-lg) 0;
    transition: background var(--transition-slow), border-color var(--transition-slow), transform var(--transition-base);
    will-change: transform;
}

.day-mode .sidebar {
    background: rgba(255, 255, 255, 0.85);
    border-right-color: rgba(0,0,0,0.08);
}

.sidebar-logo {
    color: #fff;
    text-decoration: none;
    font-size: var(--text-lg);
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: var(--space-sm) var(--space-lg) var(--space-xl);
    display: block;
    transition: color var(--transition-slow);
}

.sidebar-logo:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: -2px;
}

.day-mode .sidebar-logo {
    color: #1a1a1a;
}

.sidebar-section-title {
    color: rgba(255,255,255,0.4);
    font-size: var(--text-xs);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 600;
    padding: 0 var(--space-lg) var(--space-sm);
    transition: color var(--transition-slow);
}

.day-mode .sidebar-section-title {
    color: rgba(0,0,0,0.45);
}

.sidebar-nav {
    list-style: none;
    flex: 1;
}

.sidebar-nav-short {
    flex: 0;
    margin-bottom: var(--space-sm);
}

.sidebar-nav li a {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    font-size: var(--text-sm);
    transition: all var(--transition-fast);
    border-left: 3px solid transparent;
    min-height: 44px;
}

.day-mode .sidebar-nav li a {
    color: rgba(0,0,0,0.65);
}

.sidebar-nav li a:hover {
    background: rgba(255,255,255,0.08);
    color: #fff;
    border-left-color: #1abc9c;
}

.day-mode .sidebar-nav li a:hover {
    background: rgba(0,0,0,0.06);
    color: #1a1a1a;
    border-left-color: #1abc9c;
}

.sidebar-nav li a:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: -2px;
    background: rgba(255,255,255,0.08);
}

.sidebar-nav li a .dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    flex-shrink: 0;
}

.sidebar-user {
    border-top: 1px solid rgba(255,255,255,0.06);
    padding: var(--space-md) var(--space-lg) var(--space-sm);
    transition: border-color var(--transition-slow);
}

.day-mode .sidebar-user {
    border-top-color: rgba(0,0,0,0.08);
}

.sidebar-user a {
    display: block;
    padding: var(--space-sm) 0;
    color: rgba(255,255,255,0.6);
    text-decoration: none;
    font-size: var(--text-sm);
    transition: color var(--transition-fast);
    min-height: 44px;
    display: flex;
    align-items: center;
}

.day-mode .sidebar-user a {
    color: rgba(0,0,0,0.55);
}

.sidebar-user a:hover {
    color: #1abc9c;
}

.sidebar-user a:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: 2px;
}

.sidebar-user .user-name {
    color: #1abc9c;
    font-weight: 600;
    font-size: var(--text-sm);
    margin-bottom: var(--space-xs);
}

/* ── Flash Messages ── */
.flash-container {
    padding: 0 32px;
    margin-left: 200px;
    position: relative;
    z-index: 50;
}

.flash {
    padding: 10px 16px;
    border-radius: 6px;
    margin-bottom: 8px;
    font-size: 14px;
}

.flash-success { background: rgba(26,188,156,0.15); border: 1px solid rgba(26,188,156,0.3); color: #1abc9c; }
.flash-error { background: rgba(231,76,60,0.15); border: 1px solid rgba(231,76,60,0.3); color: #e74c3c; }

/* ── Content ── */
.content {
    flex: 1;
    padding: 32px;
    max-width: 960px;
    margin: 0 auto;
    margin-left: 232px;
    width: calc(100% - 200px);
}

/* ── Footer ── */
.site-footer {
    text-align: center;
    padding: 20px;
    margin-left: 200px;
    color: rgba(255,255,255,0.3);
    font-size: 12px;
    border-top: 1px solid rgba(255,255,255,0.05);
    transition: color 0.6s ease, border-color 0.6s ease;
}
.day-mode .site-footer {
    color: rgba(0,0,0,0.35);
    border-top-color: rgba(0,0,0,0.08);
}

/* ── Social Footer ── */
.social-footer {
    text-align: center;
    margin-left: 200px;
    padding: 16px 20px;
}
.social-footer-inner {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: rgba(255,255,255,0.6);
    font-size: 13px;
    opacity: 0.7;
    transition: opacity 0.3s;
}
.social-footer-inner:hover { opacity: 1; }
.day-mode .social-footer-inner { color: rgba(0,0,0,0.5); }
.social-link {
    font-size: 20px;
    text-decoration: none;
    transition: transform 0.2s;
    display: inline-block;
}
.social-link:hover { transform: scale(1.3); }
.footer-hint {
    font-size: 11px;
    opacity: 0.7;
    margin-left: 4px;
}

/* ── Category Page ── */
.category-header {
    text-align: center;
    margin-bottom: 32px;
}

.category-header h1 {
    font-size: 28px;
    color: #fff;
    margin-bottom: 8px;
    transition: color 0.6s ease;
}
.day-mode .category-header h1 { color: #333; }

.tag-bar {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 24px;
}

.tag-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-full);
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.12);
    color: rgba(255,255,255,0.6);
    text-decoration: none;
    font-size: var(--text-sm);
    transition: all var(--transition-fast);
    min-height: 44px;
    white-space: nowrap;
}
.day-mode .tag-btn {
    background: rgba(0,0,0,0.04);
    border-color: rgba(0,0,0,0.1);
    color: rgba(0,0,0,0.5);
}

.tag-btn:hover, .tag-btn.active {
    background: rgba(26,188,156,0.2);
    border-color: rgba(26,188,156,0.4);
    color: #1abc9c;
    transform: translateY(-1px);
}

.tag-btn:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: 2px;
}

.article-list { list-style: none; }

.article-card {
    display: block;
    padding: var(--space-lg);
    margin-bottom: var(--space-md);
    border-radius: var(--radius-lg);
    background: rgba(255,255,255,0.04);
    border: 1px solid rgba(255,255,255,0.06);
    text-decoration: none;
    transition: all var(--transition-fast);
}
.day-mode .article-card {
    background: rgba(255,255,255,0.5);
    border-color: rgba(0,0,0,0.06);
}

.article-card:hover {
    background: rgba(255,255,255,0.08);
    border-color: rgba(255,255,255,0.12);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}
.day-mode .article-card:hover {
    background: rgba(255,255,255,0.7);
    border-color: rgba(0,0,0,0.1);
}

.article-card:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: 2px;
    transform: translateY(-2px);
}

.article-card h2 {
    color: #fff;
    font-size: var(--text-lg);
    margin-bottom: var(--space-sm);
    transition: color var(--transition-slow);
}
.day-mode .article-card h2 { color: #333; }

.article-meta {
    display: flex;
    gap: var(--space-md);
    align-items: center;
    flex-wrap: wrap;
    font-size: var(--text-xs);
    color: rgba(255,255,255,0.5);
}
.day-mode .article-meta { color: rgba(0,0,0,0.5); }

.article-tag {
    background: rgba(155,89,182,0.2);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-full);
    color: #bb8fce;
    font-size: var(--text-xs);
    transition: all var(--transition-fast);
    display: inline-block;
}
.day-mode .article-tag {
    background: rgba(155,89,182,0.12);
    color: #8e44ad;
}

.article-tag:hover {
    background: rgba(155,89,182,0.3);
    transform: translateY(-1px);
}
.day-mode .article-tag:hover {
    background: rgba(155,89,182,0.2);
}

.empty-state {
    text-align: center;
    color: rgba(255,255,255,0.3);
    padding: 48px 0;
    font-size: 16px;
}
.day-mode .empty-state { color: rgba(0,0,0,0.35); }

/* ── Article Page ── */
.article-detail h1 {
    font-size: 26px;
    color: #fff;
    margin-bottom: 12px;
    transition: color 0.6s ease;
}
.day-mode .article-detail h1 { color: #333; }

.article-info {
    display: flex;
    gap: 16px;
    align-items: center;
    margin-bottom: 24px;
    font-size: 13px;
    color: rgba(255,255,255,0.4);
}
.day-mode .article-info { color: rgba(0,0,0,0.45); }

.article-body {
    line-height: 1.8;
    color: rgba(255,255,255,0.85);
    transition: color 0.6s ease;
}
.day-mode .article-body { color: rgba(0,0,0,0.75); }

.article-body h2 { color: #1abc9c; margin: 24px 0 12px; font-size: 20px; }
.article-body h3 { color: #3498db; margin: 20px 0 10px; font-size: 17px; }
.day-mode .article-body h2 { color: #16a085; }
.day-mode .article-body h3 { color: #2980b9; }

.article-body ul, .article-body ol { margin-left: 20px; margin-bottom: 12px; }
.article-body li { margin-bottom: 4px; }
.article-body blockquote {
    border-left: 3px solid #1abc9c;
    padding: 8px 16px;
    margin: 12px 0;
    background: rgba(26,188,156,0.05);
    color: rgba(255,255,255,0.7);
}
.day-mode .article-body blockquote {
    background: rgba(26,188,156,0.08);
    color: rgba(0,0,0,0.6);
}
.article-body code {
    background: rgba(255,255,255,0.08);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 13px;
}
.day-mode .article-body code {
    background: rgba(0,0,0,0.06);
    color: #c0392b;
}
.article-body pre {
    background: rgba(0,0,0,0.4);
    padding: 16px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 12px 0;
}
.day-mode .article-body pre {
    background: rgba(0,0,0,0.06);
}

/* ── Comments ── */
.comments-section {
    margin-top: 40px;
    border-top: 1px solid rgba(255,255,255,0.08);
    padding-top: 24px;
}
.day-mode .comments-section { border-top-color: rgba(0,0,0,0.08); }

.comments-section h3 {
    color: #fff;
    margin-bottom: 16px;
    font-size: 18px;
}
.day-mode .comments-section h3 { color: #333; }

.comment-item {
    padding: 12px 16px;
    background: rgba(255,255,255,0.03);
    border-radius: 8px;
    margin-bottom: 10px;
    border: 1px solid rgba(255,255,255,0.05);
}
.day-mode .comment-item {
    background: rgba(255,255,255,0.5);
    border-color: rgba(0,0,0,0.06);
}

.comment-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 6px;
    font-size: 12px;
}

.comment-user { color: #1abc9c; font-weight: bold; }
.comment-time { color: rgba(255,255,255,0.3); }
.day-mode .comment-time { color: rgba(0,0,0,0.35); }
.comment-body { color: rgba(255,255,255,0.7); font-size: 14px; line-height: 1.6; }
.day-mode .comment-body { color: rgba(0,0,0,0.65); }

.comment-form {
    margin-top: var(--space-lg);
}

.comment-form textarea {
    width: 100%;
    min-height: 100px;
    padding: var(--space-md);
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius-md);
    color: #e0e0e0;
    font-family: inherit;
    font-size: var(--text-sm);
    resize: vertical;
    transition: all var(--transition-fast);
    line-height: 1.6;
}
.day-mode .comment-form textarea {
    background: rgba(255,255,255,0.6);
    border-color: rgba(0,0,0,0.12);
    color: #333;
}

.comment-form textarea:focus {
    outline: none;
    border-color: #1abc9c;
    box-shadow: 0 0 0 3px rgba(26,188,156,0.1);
}

.comment-form-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: var(--space-sm);
    gap: var(--space-md);
}

.comment-hint {
    font-size: var(--text-xs);
    color: rgba(255,255,255,0.4);
}
.day-mode .comment-hint {
    color: rgba(0,0,0,0.4);
}

.login-prompt {
    color: rgba(255,255,255,0.5);
    margin-top: var(--space-md);
    font-size: var(--text-sm);
}
.day-mode .login-prompt {
    color: rgba(0,0,0,0.5);
}

.login-prompt a {
    color: #1abc9c;
    text-decoration: none;
    font-weight: 600;
}
.login-prompt a:hover {
    text-decoration: underline;
}

/* Visually hidden but accessible to screen readers */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition-fast);
    min-height: 44px;
    min-width: 44px;
}

.btn-primary {
    background: #1abc9c;
    color: #fff;
}

.btn-primary:hover {
    background: #16a085;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-primary:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: 2px;
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-danger {
    background: rgba(231,76,60,0.2);
    color: #e74c3c;
    border: 1px solid rgba(231,76,60,0.3);
}

.btn-danger:hover { background: rgba(231,76,60,0.3); }

.btn-sm { padding: 4px 12px; font-size: 12px; }

/* ── Forms (Login/Register) ── */
.auth-container {
    max-width: 400px;
    margin: 60px auto;
}

.auth-container h1 {
    text-align: center;
    color: #fff;
    margin-bottom: 24px;
    font-size: 24px;
    transition: color 0.6s ease;
}
.day-mode .auth-container h1 { color: #333; }

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    color: rgba(255,255,255,0.6);
    font-size: 13px;
}
.day-mode .form-group label { color: rgba(0,0,0,0.55); }

.password-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.password-wrapper input {
    width: 100%;
    padding-right: 48px;
}

.password-toggle {
    position: absolute;
    right: 1px;
    top: 1px;
    bottom: 1px;
    background: rgba(255,255,255,0.05);
    border: none;
    border-left: 1px solid rgba(255,255,255,0.1);
    border-radius: 0 5px 5px 0;
    cursor: pointer;
    color: rgba(255,255,255,0.5);
    padding: 0;
    width: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.password-toggle:hover {
    background: rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.8);
}

.day-mode .password-toggle {
    background: rgba(0,0,0,0.03);
    border-left-color: rgba(0,0,0,0.1);
    color: rgba(0,0,0,0.5);
}

.day-mode .password-toggle:hover {
    background: rgba(0,0,0,0.06);
    color: rgba(0,0,0,0.8);
}

.password-toggle:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: -2px;
}

/* Hide browser native password reveal button (Edge/Chrome) */
input[type="password"]::-ms-reveal,
input[type="password"]::-ms-clear {
    display: none;
}

.eye-icon {
    width: 20px;
    height: 20px;
}

.eye-icon.eye-closed {
    display: none;
}

.password-toggle[aria-label="隐藏密码"] .eye-open {
    display: none;
}

.password-toggle[aria-label="隐藏密码"] .eye-closed {
    display: block;
}

.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 10px 14px;
    background-color: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 6px;
    color: #e0e0e0;
    font-family: inherit;
    font-size: 14px;
    transition: background-color 0.6s ease, border-color 0.6s ease, color 0.6s ease;
}
.day-mode .form-group input,
.day-mode .form-group textarea {
    background-color: rgba(255,255,255,0.6);
    border-color: rgba(0,0,0,0.12);
    color: #333;
}
.day-mode .form-group select {
    border-color: rgba(0,0,0,0.12);
    color: #333;
}

.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
    outline: none;
    border-color: rgba(26,188,156,0.4);
}

/* Select dropdown styling */
.form-group select {
    cursor: pointer;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background: rgba(255,255,255,0.05) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23e0e0e0' d='M6 9L1 4h10z'/%3E%3C/svg%3E") no-repeat right 12px center;
    padding-right: 36px;
}

.day-mode .form-group select {
    background: rgba(255,255,255,0.6) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23333' d='M6 9L1 4h10z'/%3E%3C/svg%3E") no-repeat right 12px center;
}

.form-group select option {
    background: #0a0e1a;
    color: #e0e0e0;
    padding: 8px 12px;
}

.day-mode .form-group select option {
    background: #ffffff;
    color: #333;
}

.form-group textarea {
    min-height: 200px;
    resize: vertical;
}

.auth-link {
    text-align: center;
    margin-top: 16px;
    font-size: 13px;
    color: rgba(255,255,255,0.4);
}
.day-mode .auth-link { color: rgba(0,0,0,0.4); }

.auth-link a { color: #1abc9c; text-decoration: none; }
.auth-link a:hover { text-decoration: underline; }

/* Review notice */
.review-notice {
    color: rgba(255,255,255,0.6);
    margin-bottom: 20px;
    font-size: 14px;
}
.day-mode .review-notice {
    color: rgba(0,0,0,0.5);
}

/* Form hint text */
.form-hint {
    display: block;
    margin-top: 4px;
    color: rgba(255,255,255,0.4);
    font-size: 12px;
}
.day-mode .form-hint {
    color: rgba(0,0,0,0.4);
}

/* ── Admin ── */
.admin-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.admin-header h1 { color: #fff; font-size: 24px; }
.day-mode .admin-header h1 { color: #333; }

.admin-section {
    margin-bottom: 32px;
}

.admin-section h2 {
    color: #1abc9c;
    font-size: 18px;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}
.day-mode .admin-section h2 { border-bottom-color: rgba(0,0,0,0.08); }

.admin-table {
    width: 100%;
    border-collapse: collapse;
}

.admin-table th, .admin-table td {
    padding: 10px 12px;
    text-align: left;
    border-bottom: 1px solid rgba(255,255,255,0.06);
    font-size: 13px;
}
.day-mode .admin-table th,
.day-mode .admin-table td {
    border-bottom-color: rgba(0,0,0,0.06);
}

.admin-table th {
    color: rgba(255,255,255,0.5);
    font-weight: normal;
}
.day-mode .admin-table th { color: rgba(0,0,0,0.45); }

.admin-table td { color: rgba(255,255,255,0.8); }
.day-mode .admin-table td { color: rgba(0,0,0,0.7); }

/* Category filter in admin dashboard */
.category-filter-select {
    padding: 8px 36px 8px 12px;
    border: 1px solid rgba(26,188,156,0.3);
    color: #1abc9c;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all var(--transition-fast);
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background: rgba(26,188,156,0.15) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%231abc9c' d='M6 9L1 4h10z'/%3E%3C/svg%3E") no-repeat right 12px center;
}

.category-filter-select:hover {
    background: rgba(26,188,156,0.25) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%231abc9c' d='M6 9L1 4h10z'/%3E%3C/svg%3E") no-repeat right 12px center;
    border-color: rgba(26,188,156,0.5);
}

.category-filter-select:focus {
    outline: none;
    border-color: #1abc9c;
    box-shadow: 0 0 0 3px rgba(26,188,156,0.2);
}

.category-filter-select option {
    background: #0a0e1a;
    color: #e0e0e0;
    padding: 8px 12px;
}

.day-mode .category-filter-select {
    background: rgba(26,188,156,0.1) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2316a085' d='M6 9L1 4h10z'/%3E%3C/svg%3E") no-repeat right 12px center;
    border-color: rgba(26,188,156,0.3);
    color: #16a085;
}

.day-mode .category-filter-select:hover {
    background: rgba(26,188,156,0.2) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2316a085' d='M6 9L1 4h10z'/%3E%3C/svg%3E") no-repeat right 12px center;
}

.day-mode .category-filter-select option {
    background: #ffffff;
    color: #333;
}

/* ── Section Nav (page.html jump buttons) ── */
.section-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 24px;
    padding: 14px 0;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    position: sticky;
    top: 0;
    background: transparent;
    z-index: 50;
    transition: background 0.6s ease, border-color 0.6s ease;
}
.day-mode .section-nav {
    background: transparent;
    border-bottom-color: rgba(0,0,0,0.08);
}

.section-btn {
    display: inline-block;
    padding: 6px 16px;
    border-radius: 20px;
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.12);
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    font-size: 13px;
    transition: all 0.2s;
}
.day-mode .section-btn {
    background: rgba(0,0,0,0.04);
    border-color: rgba(0,0,0,0.1);
    color: rgba(0,0,0,0.5);
}

.section-btn:hover {
    background: rgba(26,188,156,0.2);
    border-color: rgba(26,188,156,0.4);
    color: #1abc9c;
}

/* ── Back Link ── */
.back-link {
    display: inline-flex;
    align-items: center;
    margin-bottom: var(--space-lg);
    padding: var(--space-sm) var(--space-md);
    color: rgba(255,255,255,0.5);
    text-decoration: none;
    font-size: var(--text-sm);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    min-height: 44px;
}
.day-mode .back-link { color: rgba(0,0,0,0.5); }

.back-link:hover {
    color: #1abc9c;
    background: rgba(26,188,156,0.1);
}

.back-link:focus-visible {
    outline: 2px solid #1abc9c;
    outline-offset: 2px;
}

/* ── Responsive Design ── */

/* Tablet (768px - 1024px) */
@media (max-width: 1024px) {
    .content {
        max-width: 100%;
        padding: var(--space-xl) var(--space-lg);
    }

    .theme-toggle {
        top: var(--space-lg);
        right: var(--space-lg);
        padding: var(--space-sm) var(--space-md);
        font-size: var(--text-sm);
    }

    .article-card {
        padding: var(--space-md);
    }

    .tag-bar {
        gap: var(--space-sm);
    }
}

/* Mobile (max-width: 768px) */
@media (max-width: 768px) {
    body {
        background-size: 150px 150px;
    }

    /* Show mobile menu toggle */
    .mobile-menu-toggle {
        display: flex;
        align-items: center;
        justify-content: center;
    }

    /* Sidebar becomes overlay */
    .sidebar {
        transform: translateX(-100%);
        transition: transform var(--transition-base), background var(--transition-slow), border-color var(--transition-slow);
        box-shadow: var(--shadow-xl);
        z-index: 1001;
    }

    .sidebar.active {
        transform: translateX(0);
    }

    /* Content takes full width */
    .content {
        margin-left: 0;
        width: 100%;
        padding: 80px var(--space-lg) var(--space-lg);
    }

    .flash-container {
        margin-left: 0;
        padding: 0 var(--space-lg);
    }

    .social-footer {
        margin-left: 0;
    }

    .site-footer {
        margin-left: 0;
    }

    /* Theme toggle repositioned */
    .theme-toggle {
        top: var(--space-lg);
        right: var(--space-lg);
        padding: var(--space-sm) var(--space-md);
        font-size: var(--text-xs);
        gap: var(--space-xs);
    }

    #themeText {
        display: none;
    }

    /* Category/Article cards */
    .category-header h1 {
        font-size: var(--text-xl);
    }

    .article-card {
        padding: var(--space-md);
    }

    .article-card h2 {
        font-size: var(--text-base);
    }

    /* Tag bar */
    .tag-bar {
        gap: var(--space-xs);
        justify-content: flex-start;
    }

    .tag-btn {
        padding: var(--space-xs) var(--space-md);
        font-size: var(--text-xs);
        min-height: 40px;
    }

    /* Article detail */
    .article-detail h1 {
        font-size: var(--text-xl);
    }

    .article-info {
        flex-wrap: wrap;
        gap: var(--space-sm);
        font-size: var(--text-xs);
    }

    .article-body {
        font-size: var(--text-sm);
    }

    .article-body h2 {
        font-size: var(--text-lg);
    }

    .article-body h3 {
        font-size: var(--text-base);
    }

    .article-body pre {
        padding: var(--space-md);
        font-size: var(--text-xs);
        overflow-x: auto;
    }

    /* Comments */
    .comment-item {
        padding: var(--space-sm) var(--space-md);
    }

    .comment-body {
        font-size: var(--text-sm);
    }

    .comment-form textarea {
        min-height: 80px;
        font-size: var(--text-sm);
    }

    /* Auth forms */
    .auth-container {
        margin: var(--space-2xl) auto;
        padding: 0 var(--space-lg);
    }

    .auth-container h1 {
        font-size: var(--text-xl);
    }

    /* Admin */
    .admin-table {
        font-size: var(--text-xs);
    }

    .admin-table th,
    .admin-table td {
        padding: var(--space-sm) var(--space-xs);
    }

    .admin-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-md);
    }

    .admin-header h1 {
        font-size: var(--text-xl);
    }

    /* Section nav */
    .section-nav {
        gap: var(--space-xs);
        padding: var(--space-sm) 0;
    }

    .section-btn {
        padding: var(--space-xs) var(--space-md);
        font-size: var(--text-xs);
        min-height: 40px;
    }
}

/* Small mobile (max-width: 480px) */
@media (max-width: 480px) {
    .content {
        padding: 70px var(--space-md) var(--space-md);
    }

    .flash-container {
        padding: 0 var(--space-md);
    }

    .category-header h1 {
        font-size: var(--text-lg);
    }

    .article-detail h1 {
        font-size: var(--text-lg);
    }

    .article-card {
        padding: var(--space-md);
    }

    .tag-bar {
        gap: var(--space-xs);
    }

    .tag-btn {
        padding: var(--space-xs) var(--space-sm);
        font-size: var(--text-xs);
        min-height: 36px;
    }

    .btn {
        width: 100%;
        text-align: center;
        justify-content: center;
    }

    .comment-form-footer {
        flex-direction: column;
        align-items: stretch;
    }

    .admin-table {
        display: block;
        overflow-x: auto;
    }

    .auth-container {
        padding: 0 var(--space-md);
    }
}