:root {
    --primary-color: #111827;
    --primary-dark: #000000;
    --primary-light: #374151;

    --accent-color: #111827;
    --accent-hover: #1f2937;

    --bg-primary: #ffffff;
    --bg-secondary: #fafafa;
    --bg-tertiary: #f5f5f5;
    --bg-card: #ffffff;

    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-tertiary: #9ca3af;

    --border-color: #e5e7eb;
    --border-light: #f3f4f6;
    --shadow-subtle: 0 1px 3px 0 rgba(0, 0, 0, 0.05);
    --shadow-card: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-hover: 0 4px 6px -1px rgba(0, 0, 0, 0.08);

    --font-primary: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter",
        sans-serif;
    --font-heading: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    --radius-sm: 0.25rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 0.75rem;

    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);

    --container-width: 1280px;
}

@media (prefers-color-scheme: dark) {
    :root {
        --primary-color: #f3f4f6;
        --primary-dark: #ffffff;
        --primary-light: #d1d5db;

        --accent-color: #ffffff;
        --accent-hover: #e5e7eb;

        --bg-primary: #1f2937;
        --bg-secondary: #111827;
        --bg-tertiary: #374151;
        --bg-card: #2f3743;

        --text-primary: #f3f4f6;
        --text-secondary: #a1a1aa;
        --text-tertiary: #6b7280;

        --border-color: #374151;
        --border-light: #4b5563;
        --shadow-subtle: 0 1px 3px 0 rgba(0, 0, 0, 0.3);
        --shadow-card: 0 1px 2px 0 rgba(0, 0, 0, 0.2);
        --shadow-hover: 0 4px 8px -2px rgba(0, 0, 0, 0.4);
    }

    .tool-card:hover .tool-link-icon {
        color: var(--text-primary);
    }
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-secondary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

button {
    font-family: inherit;
    border: none;
    cursor: pointer;
    background: none;
}

.home-icon {
    position: fixed;
    top: 1.5rem;
    left: 1.5rem;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    cursor: pointer;
}

.home-icon:hover {
    border-color: var(--text-primary);
    box-shadow: var(--shadow-hover);
}

.home-icon-emoji {
    font-size: 1.5rem;
    line-height: 1;
}

.header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 5rem 0 3rem;
}

.nav-container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
}

.hero {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
    text-align: center;
}

.hero-title {
    font-family: var(--font-heading);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.125rem);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-2xl);
    font-weight: 400;
}

.search-container {
    max-width: 600px;
    margin: 0 auto;
    margin-bottom: 0.75rem;
}

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

.search-icon {
    position: absolute;
    left: 1rem;
    color: var(--text-tertiary);
    pointer-events: none;
}

.search-input {
    width: 100%;
    padding: 0.875rem 3rem 0.875rem 3rem;
    font-size: 0.9375rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: all var(--transition-base);
}

.search-input:focus {
    outline: none;
    border-color: var(--text-primary);
    box-shadow: 0 0 0 3px rgba(17, 24, 39, 0.05);
}

.search-input::placeholder {
    color: var(--text-tertiary);
}

.clear-search {
    position: absolute;
    right: 0.75rem;
    width: 28px;
    height: 28px;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--text-tertiary);
    font-size: 1.25rem;
    display: none;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.clear-search:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.clear-search.visible {
    display: flex;
}

.category-nav {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    z-index: 50;
}

.category-nav-wrapper {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0.75rem var(--spacing-xl);
    display: flex;
    gap: 0.5rem;
    overflow-x: auto;
    scrollbar-width: none;
}

.category-nav-wrapper::-webkit-scrollbar {
    display: none;
}

.category-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    background: transparent;
    transition: all var(--transition-fast);
    white-space: nowrap;
    border: 1px solid transparent;
}

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

.category-btn.active {
    background: var(--text-primary);
    color: var(--bg-primary);
    border-color: var(--text-primary);
}

.category-icon {
    font-size: 1.125rem;
}

.main-content {
    padding: var(--spacing-2xl) 0;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
}

.stats-bar {
    display: flex;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg);
    background: transparent;
}

.stat {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
}

.stat-number {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    font-family: var(--font-heading);
    letter-spacing: -0.02em;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.no-results {
    text-align: center;
    padding: var(--spacing-2xl);
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.no-results-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-lg);
    opacity: 0.5;
}

.no-results h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.no-results p {
    color: var(--text-secondary);
}

.category-section {
    background: transparent;
    padding: 0;
    margin-bottom: var(--spacing-2xl);
}

.category-section.hidden {
    display: none;
}

.category-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: var(--spacing-lg);
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.category-header-icon {
    font-size: 1.5rem;
}

.category-header-title {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.category-header-count {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    font-weight: 500;
    padding: 0.25rem 0.625rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
}

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

.tool-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-base);
    cursor: pointer;
    display: flex;
    flex-direction: column;
}

.tool-card:hover {
    border-color: var(--text-primary);
    box-shadow: var(--shadow-hover);
}

.tool-card.hidden {
    display: none;
}

.tool-image-container {
    position: relative;
    width: 100%;
    height: 160px;
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-light);
}

.tool-image {
    width: 100%;
    height: 100%;
    object-fit: contain;
    object-position: center;
}

.tool-image-placeholder {
    font-size: 3rem;
    opacity: 0.2;
}

.tool-content {
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.tool-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: var(--spacing-sm);
}

.tool-name {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.3;
    letter-spacing: -0.01em;
}

.tool-link-icon {
    color: var(--text-tertiary);
    opacity: 0;
    transition: var(--transition-fast);
}

.tool-card:hover .tool-link-icon {
    opacity: 1;
    color: var(--text-primary);
}

.tool-description {
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.tool-card:hover .tool-description {
    -webkit-line-clamp: unset;
    max-height: none;
    overflow: visible;
    background: var(--bg-card);
    padding: var(--spacing-sm);
    margin: 0 calc(-1 * var(--spacing-sm)) var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: 0 0 0 1px var(--border-color);
    z-index: 10;
}

.tool-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.375rem;
    margin-bottom: var(--spacing-md);
}

.tool-tag {
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    font-weight: 500;
}

.tool-footer {
    display: flex;
    gap: 0.5rem;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-light);
    margin-top: auto;
}

.tool-btn {
    flex: 1;
    padding: 0.625rem var(--spacing-md);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    text-align: center;
    transition: all var(--transition-fast);
}

.tool-btn-primary {
    background: var(--text-primary);
    color: var(--bg-primary);
}

.tool-btn-primary:hover {
    background: var(--primary-dark);
}

.tool-btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.tool-btn-secondary:hover {
    background: var(--bg-tertiary);
}

.footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-2xl) 0 var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-xl);
    justify-items: center;
}

.footer-section h3 {
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.footer-section p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.875rem;
}

.footer-link {
    display: inline-block;
    margin-top: var(--spacing-sm);
    color: var(--text-primary);
    text-decoration: underline;
    transition: var(--transition-fast);
    font-size: 0.875rem;
}

.footer-link:hover {
    color: var(--text-secondary);
}

.cc-license img {
    margin-top: var(--spacing-sm);
    opacity: 0.7;
}

.footer-bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.category-section {
    animation: fadeIn 0.5s ease backwards;
}

.category-section:nth-child(1) {
    animation-delay: 0.1s;
}
.category-section:nth-child(2) {
    animation-delay: 0.2s;
}
.category-section:nth-child(3) {
    animation-delay: 0.3s;
}
.category-section:nth-child(4) {
    animation-delay: 0.4s;
}

@media (max-width: 768px) {
    .home-icon {
        top: 0.5cm;
        left: 0.5cm;
        width: 50px;
        height: 50px;
    }

    .home-icon-emoji {
        font-size: 1.5rem;
    }

    .hero {
        padding: var(--spacing-xl) var(--spacing-lg);
    }

    .category-nav-wrapper {
        padding: var(--spacing-md) var(--spacing-lg);
    }

    .tools-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        gap: var(--spacing-md);
    }

    .stats-bar {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }

    .menu-toggle {
        display: flex;
    }
}

@media (max-width: 480px) {
    .tools-grid {
        grid-template-columns: 1fr;
    }

    .search-input {
        padding: var(--spacing-md) var(--spacing-lg) var(--spacing-md) 3rem;
        font-size: 0.875rem;
    }

    .category-section {
        padding: var(--spacing-lg);
    }
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}