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

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --success: #16a34a;
    --warning: #d97706;
    --danger: #dc2626;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    --radius: 8px;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
    color: var(--gray-800);
    background: var(--gray-50);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--primary-dark);
}

/* ===== Header ===== */
.site-header {
    background: #fff;
    border-bottom: 1px solid var(--gray-200);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 20px;
    font-weight: 700;
    color: var(--gray-900);
}

.logo svg {
    width: 28px;
    height: 28px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 24px;
    list-style: none;
}

.nav-menu a {
    color: var(--gray-600);
    font-size: 15px;
    font-weight: 500;
    padding: 8px 0;
    position: relative;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--primary);
}

.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
    border-radius: 1px;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

/* ===== Main Content ===== */
.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
    width: 100%;
}

/* ===== Hero Section ===== */
.hero {
    text-align: center;
    padding: 60px 20px 40px;
}

.hero h1 {
    font-size: 36px;
    font-weight: 800;
    color: var(--gray-900);
    margin-bottom: 16px;
    line-height: 1.2;
}

.hero p {
    font-size: 18px;
    color: var(--gray-500);
    max-width: 600px;
    margin: 0 auto 32px;
}

/* ===== Tool Grid ===== */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 40px;
}

.tool-card {
    background: #fff;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 28px 24px;
    transition: all 0.3s;
    text-decoration: none;
    color: inherit;
    display: block;
}

.tool-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
    color: inherit;
}

.tool-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
    font-size: 24px;
}

.tool-icon.blue { background: var(--primary-light); color: var(--primary); }
.tool-icon.green { background: #dcfce7; color: var(--success); }
.tool-icon.orange { background: #fef3c7; color: var(--warning); }
.tool-icon.purple { background: #f3e8ff; color: #9333ea; }
.tool-icon.red { background: #fee2e2; color: var(--danger); }

.tool-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 8px;
}

.tool-card p {
    font-size: 14px;
    color: var(--gray-500);
    line-height: 1.5;
}

/* ===== Tool Page ===== */
.tool-page {
    max-width: 800px;
    margin: 0 auto;
}

.tool-page h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 8px;
}

.tool-page .subtitle {
    color: var(--gray-500);
    margin-bottom: 32px;
}

.input-group {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
}

.input-group input {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 15px;
    transition: border-color 0.2s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

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

.btn-primary:disabled {
    background: var(--gray-300);
    cursor: not-allowed;
}

.btn-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
}

.btn-secondary:hover {
    background: var(--gray-200);
}

/* ===== Results ===== */
.results {
    margin-top: 24px;
}

.result-card {
    background: #fff;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 16px;
}

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

.result-table th,
.result-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--gray-100);
    font-size: 14px;
}

.result-table th {
    color: var(--gray-500);
    font-weight: 500;
    white-space: nowrap;
}

.result-table td {
    color: var(--gray-800);
    word-break: break-all;
}

.status-badge {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
}

.status-badge.success { background: #dcfce7; color: var(--success); }
.status-badge.warning { background: #fef3c7; color: var(--warning); }
.status-badge.danger { background: #fee2e2; color: var(--danger); }
.status-badge.info { background: var(--primary-light); color: var(--primary); }

.loading {
    text-align: center;
    padding: 40px;
    color: var(--gray-400);
}

.loading .spinner {
    width: 32px;
    height: 32px;
    border: 3px solid var(--gray-200);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 16px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.error-msg {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: var(--danger);
    padding: 16px;
    border-radius: var(--radius);
    font-size: 14px;
}

/* ===== Blog ===== */
.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
}

.blog-card {
    background: #fff;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    overflow: hidden;
    transition: all 0.3s;
}

.blog-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--gray-300);
}

.blog-card-body {
    padding: 20px;
}

.blog-card-category {
    font-size: 12px;
    font-weight: 600;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.blog-card h3 {
    font-size: 17px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 8px;
    line-height: 1.4;
}

.blog-card h3 a {
    color: inherit;
}

.blog-card h3 a:hover {
    color: var(--primary);
}

.blog-card p {
    font-size: 14px;
    color: var(--gray-500);
    line-height: 1.6;
    margin-bottom: 12px;
}

.blog-card-meta {
    font-size: 13px;
    color: var(--gray-400);
}

/* ===== Blog Post ===== */
.blog-post {
    max-width: 760px;
    margin: 0 auto;
}

.blog-post-header {
    margin-bottom: 32px;
}

.blog-post-header h1 {
    font-size: 30px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 12px;
    line-height: 1.3;
}

.blog-post-meta {
    font-size: 14px;
    color: var(--gray-400);
}

.blog-post-body {
    font-size: 16px;
    line-height: 1.8;
    color: var(--gray-700);
}

.blog-post-body h2 {
    font-size: 22px;
    font-weight: 600;
    color: var(--gray-900);
    margin: 32px 0 16px;
}

.blog-post-body h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
    margin: 24px 0 12px;
}

.blog-post-body p {
    margin-bottom: 16px;
}

.blog-post-body ul,
.blog-post-body ol {
    margin-bottom: 16px;
    padding-left: 24px;
}

.blog-post-body li {
    margin-bottom: 8px;
}

.blog-post-body code {
    background: var(--gray-100);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 14px;
    font-family: 'SF Mono', Monaco, Consolas, monospace;
}

.blog-post-body pre {
    background: var(--gray-800);
    color: #e5e7eb;
    padding: 16px;
    border-radius: var(--radius);
    overflow-x: auto;
    margin-bottom: 16px;
}

.blog-post-body pre code {
    background: none;
    padding: 0;
    color: inherit;
}

.blog-post-body table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 16px;
}

.blog-post-body table th,
.blog-post-body table td {
    padding: 10px 14px;
    border: 1px solid var(--gray-200);
    text-align: left;
    font-size: 14px;
}

.blog-post-body table th {
    background: var(--gray-50);
    font-weight: 600;
}

.blog-post-body blockquote {
    border-left: 4px solid var(--primary);
    padding: 8px 16px;
    background: var(--gray-50);
    margin-bottom: 16px;
    color: var(--gray-600);
}

/* ===== AdSense Placeholder ===== */
.ad-container {
    margin: 32px 0;
    text-align: center;
}

.ad-placeholder {
    background: var(--gray-100);
    border: 1px dashed var(--gray-300);
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
    color: var(--gray-400);
    font-size: 13px;
}

/* ===== Info Pages ===== */
.info-page {
    max-width: 760px;
    margin: 0 auto;
}

.info-page h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 24px;
}

.info-page h2 {
    font-size: 20px;
    font-weight: 600;
    color: var(--gray-900);
    margin: 24px 0 12px;
}

.info-page p {
    margin-bottom: 16px;
    color: var(--gray-700);
}

.info-page ul {
    margin-bottom: 16px;
    padding-left: 24px;
}

.info-page li {
    margin-bottom: 8px;
    color: var(--gray-700);
}

/* ===== Back Link ===== */
.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--gray-500);
    font-size: 14px;
    margin-bottom: 24px;
}

.back-link:hover {
    color: var(--primary);
}

/* ===== Footer ===== */
.site-footer {
    background: var(--gray-900);
    color: var(--gray-400);
    padding: 40px 20px 20px;
    margin-top: 60px;
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
}

.footer-brand p {
    font-size: 14px;
    margin-top: 12px;
    line-height: 1.6;
}

.footer-col h4 {
    color: #fff;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 12px;
}

.footer-col ul {
    list-style: none;
}

.footer-col li {
    margin-bottom: 8px;
}

.footer-col a {
    color: var(--gray-400);
    font-size: 14px;
}

.footer-col a:hover {
    color: #fff;
}

.footer-bottom {
    max-width: 1200px;
    margin: 32px auto 0;
    padding-top: 20px;
    border-top: 1px solid var(--gray-700);
    text-align: center;
    font-size: 13px;
    color: var(--gray-500);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .header-inner {
        padding: 0 16px;
    }

    .nav-menu {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .nav-menu.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: #fff;
        border-bottom: 1px solid var(--gray-200);
        padding: 16px;
        gap: 16px;
    }

    .hero h1 {
        font-size: 26px;
    }

    .hero p {
        font-size: 16px;
    }

    .input-group {
        flex-direction: column;
    }

    .footer-inner {
        grid-template-columns: 1fr 1fr;
        gap: 24px;
    }

    .tool-grid {
        grid-template-columns: 1fr;
    }

    .blog-grid {
        grid-template-columns: 1fr;
    }

    .main-content {
        padding: 24px 16px;
    }
}