:root {
    --primary: #4f46e5;
    --primary-dark: #4338ca;
    --secondary: #10b981;
    --bg: #f8fafc;
    --bg-dark: #0f172a;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --card-bg: #ffffff;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f172a;
        --text: #f1f5f9;
        --text-light: #94a3b8;
        --border: #334155;
        --card-bg: #1e293b;
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
}

.lang-switcher {
    background: var(--bg);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 0.85rem;
    cursor: pointer;
    outline: none;
    transition: border-color 0.2s;
}

.lang-switcher:hover {
    border-color: var(--primary);
}

.lang-switcher:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.2);
}

.nav {
    display: flex;
    gap: 24px;
    align-items: center;
}

.nav a {
    color: var(--text);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s;
}

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

.premium-link {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white !important;
    padding: 6px 16px;
    border-radius: 20px;
    font-weight: 500;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text);
}

@media (max-width: 768px) {
    .nav {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: var(--card-bg);
        flex-direction: column;
        padding: 20px;
        gap: 16px;
        border-bottom: 1px solid var(--border);
    }
    .nav.active {
        display: flex;
    }
    .mobile-menu-btn {
        display: block;
    }
}

.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 60px 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.hero p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.ad-container {
    max-width: 728px;
    margin: 20px auto;
    min-height: 90px;
    background: var(--card-bg);
    border: 1px dashed var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    font-size: 0.9rem;
}

.tools-grid {
    padding: 60px 0;
}

.tools-grid h2 {
    text-align: center;
    margin-bottom: 40px;
    font-size: 1.8rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.tool-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
    text-decoration: none;
    color: var(--text);
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
}

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

.tool-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.tool-card h3 {
    font-size: 1.2rem;
    margin-bottom: 8px;
}

.tool-card p {
    color: var(--text-light);
    font-size: 0.9rem;
}

.tool-tag {
    position: absolute;
    top: 16px;
    right: 16px;
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
}

.tool-tag.free {
    background: #dcfce7;
    color: #166534;
}

.tool-tag.premium {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
}

.support-section {
    background: var(--card-bg);
    padding: 60px 0;
    text-align: center;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.support-section h2 {
    margin-bottom: 16px;
}

.support-section p {
    color: var(--text-light);
    margin-bottom: 24px;
}

.donate-btn {
    display: inline-block;
}

.premium-section {
    padding: 60px 0;
    text-align: center;
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--bg-dark) 100%);
    color: white;
}

.premium-section h2 {
    margin-bottom: 24px;
}

.premium-features {
    list-style: none;
    max-width: 400px;
    margin: 0 auto 24px;
    text-align: left;
}

.premium-features li {
    padding: 8px 0;
    font-size: 1.1rem;
}

.premium-price {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 24px;
}

.premium-btn {
    display: inline-block;
    background: white;
    color: var(--primary);
    padding: 12px 32px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.2s;
}

.premium-btn:hover {
    transform: scale(1.05);
}

.footer {
    background: var(--card-bg);
    border-top: 1px solid var(--border);
    padding: 40px 0;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--primary);
}

.footer p {
    color: var(--text-light);
    font-size: 0.85rem;
}

.tool-page {
    padding: 40px 0;
}

.tool-container {
    max-width: 900px;
    margin: 0 auto;
}

.tool-header {
    text-align: center;
    margin-bottom: 32px;
}

.tool-header h1 {
    font-size: 2rem;
    margin-bottom: 8px;
}

.tool-header p {
    color: var(--text-light);
}

.tool-body {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--bg);
    color: var(--text);
    font-family: inherit;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

textarea.form-control {
    min-height: 200px;
    resize: vertical;
    font-family: 'Consolas', 'Monaco', monospace;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

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

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

.btn-secondary {
    background: var(--border);
    color: var(--text);
}

.btn-secondary:hover {
    background: #d1d5db;
}

.btn-group {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.output-area {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    min-height: 100px;
    font-family: 'Consolas', 'Monaco', monospace;
    white-space: pre-wrap;
    word-break: break-all;
}

.premium-lock {
    position: relative;
}

.premium-lock::after {
    content: '🔒 高级功能';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
}

.options-row {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.range-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

.range-group input[type="range"] {
    width: 150px;
}

.range-value {
    min-width: 30px;
    text-align: center;
    font-weight: 600;
}

.copy-btn {
    position: absolute;
    top: 8px;
    right: 8px;
    background: var(--primary);
    color: white;
    border: none;
    padding: 6px 12px;
    border-radius: 4px;
    font-size: 0.85rem;
    cursor: pointer;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.copy-btn:hover {
    opacity: 1;
}

.output-wrapper {
    position: relative;
}

.qrcode-output {
    display: flex;
    justify-content: center;
    padding: 20px;
    background: white;
    border-radius: 8px;
}

.notification {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--secondary);
    color: white;
    padding: 12px 24px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s;
    z-index: 1000;
}

.file-upload-wrapper {
    display: flex;
    align-items: center;
    gap: 12px;
}

.file-upload-input {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
    pointer-events: none;
}

.file-upload-btn {
    cursor: pointer;
}

.file-upload-names {
    color: var(--text-light);
    font-size: 0.9rem;
}

.notification.show {
    transform: translateY(0);
    opacity: 1;
}