:root {
    --primary-color: #0ea5a0;
    --primary-dark: #0d9488;
    --primary-light: #14b8a6;
    --secondary-color: #06b6b5;
    --accent-color: #f59e0b;
    --success-color: #22c55e;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --info-color: #0ea5a0;
    
    --text-primary: #1a1a2e;
    --text-secondary: #5a6d7e;
    --text-muted: #8a9aaa;
    
    --bg-primary: #f4f7f6;
    --bg-secondary: #f8faf9;
    --bg-card: #ffffff;
    
    --border-color: #e2e8e5;
    --border-light: #edf2ef;
    
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.03);
    --shadow-md: 0 4px 16px rgba(14, 165, 160, 0.08);
    --shadow-lg: 0 8px 30px rgba(14, 165, 160, 0.10);
    
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-slow: 0.35s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

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

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

.hero {
    text-align: center;
    padding: 40px 30px;
    background: linear-gradient(135deg, #0d9488 0%, #06b6b5 50%, #14b8a6 100%);
    border-radius: var(--radius-lg);
    margin-bottom: 32px;
    box-shadow: 0 8px 32px rgba(13, 148, 136, 0.15);
}

.hero h1 {
    font-size: 32px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}

.hero p {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.85);
}

.category-section {
    margin-bottom: 36px;
}

.category-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    padding: 14px 20px;
    background: #ecfaf8;
    border-radius: var(--radius-md);
    border-left: 4px solid var(--primary-color);
}

.category-icon {
    font-size: 24px;
}

.category-title {
    font-size: 17px;
    font-weight: 600;
    color: var(--text-primary);
}

.category-count {
    font-size: 13px;
    color: var(--text-muted);
    font-weight: 400;
    margin-left: 8px;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.tool-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    cursor: pointer;
    border: 1px solid var(--border-color);
    position: relative;
}

.tool-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.tool-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 12px;
}

.tool-icon-wrapper {
    width: 44px;
    height: 44px;
    border-radius: 10px;
    background: linear-gradient(135deg, #0d9488 0%, #06b6b5 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: #fff;
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(13, 148, 136, 0.2);
}

.tool-icon-wrapper::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 30%, rgba(255,255,255,0.25) 0%, transparent 60%);
    pointer-events: none;
}

.tool-card:nth-child(3n+1) .tool-icon-wrapper {
    background: linear-gradient(135deg, #0d9488 0%, #06b6b5 100%);
}

.tool-card:nth-child(3n+2) .tool-icon-wrapper {
    background: linear-gradient(135deg, #14b8a6 0%, #0ea5a0 100%);
}

.tool-card:nth-child(3n+3) .tool-icon-wrapper {
    background: linear-gradient(135deg, #14b8a6 0%, #0d9488 100%);
}

.tool-name {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.guest-tag {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 10px;
    font-weight: 500;
    margin-top: 4px;
}

.guest-tag.available {
    background: #d1fae5;
    color: #059669;
}

.guest-tag.login-required {
    background: #fef3c7;
    color: #d97706;
}

.guest-tag.user-available {
    background: #ccfbf1;
    color: #0d9488;
}

.tool-desc {
    color: var(--text-secondary);
    font-size: 13px;
    line-height: 1.5;
    margin-bottom: 14px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.tool-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 12px;
    border-top: 1px dashed var(--border-light);
}

.tool-usage {
    font-size: 12px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 4px;
}

.tool-action {
    color: var(--primary-color);
    font-size: 12px;
    font-weight: 550;
    display: flex;
    align-items: center;
    gap: 4px;
    transition: color var(--transition-fast);
}

.tool-card:hover .tool-action {
    color: var(--primary-dark);
}

/* 平板端 (768px - 1024px) */
@media (max-width: 1024px) {
    .container {
        padding: 0 20px;
    }
    
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 14px;
    }
    
    .hero {
        padding: 32px 24px;
    }
    
    .hero h1 {
        font-size: 28px;
    }
    
    .hero p {
        font-size: 15px;
    }
    
    .tool-card {
        padding: 18px;
    }
    
    .tool-icon-wrapper {
        width: 40px;
        height: 40px;
        font-size: 18px;
    }
    
    .tool-name {
        font-size: 15px;
    }
    
    .tool-desc {
        font-size: 12.5px;
    }
}

/* 手机端 (480px - 768px) */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
        gap: 14px;
    }
    
    .hero {
        padding: 24px 16px;
        border-radius: var(--radius-md);
    }
    
    .hero h1 {
        font-size: 24px;
        margin-bottom: 8px;
    }
    
    .hero p {
        font-size: 14px;
    }
    
    .category-section {
        margin-bottom: 28px;
    }
    
    .category-header {
        padding: 12px 16px;
        gap: 10px;
    }
    
    .category-icon {
        font-size: 20px;
    }
    
    .category-title {
        font-size: 15px;
    }
    
    .category-count {
        font-size: 12px;
    }
    
    .tool-card {
        padding: 16px;
        box-shadow: var(--shadow-sm);
        border: 1px solid var(--border-light);
    }
    
    .tool-card:active {
        transform: scale(0.98);
        box-shadow: var(--shadow-md);
    }
    
    .tool-header {
        gap: 12px;
        margin-bottom: 10px;
    }
    
    .tool-icon-wrapper {
        width: 38px;
        height: 38px;
        font-size: 17px;
    }
    
    .tool-name {
        font-size: 15px;
        font-weight: 600;
    }
    
    .guest-tag {
        padding: 2px 8px;
        font-size: 9px;
        margin-top: 3px;
    }
    
    .tool-desc {
        font-size: 12px;
        line-height: 1.5;
        margin-bottom: 12px;
    }
    
    .tool-footer {
        padding-top: 10px;
    }
    
    .tool-usage {
        font-size: 11px;
    }
    
    .tool-action {
        font-size: 11.5px;
        font-weight: 550;
    }
}

/* 小屏手机 (< 480px) */
@media (max-width: 480px) {
    .container {
        padding: 0 12px;
    }
    
    .hero {
        padding: 20px 14px;
    }
    
    .hero h1 {
        font-size: 20px;
        letter-spacing: -0.3px;
    }
    
    .hero p {
        font-size: 13px;
    }
    
    .category-header {
        padding: 10px 14px;
    }
    
    .category-icon {
        font-size: 18px;
    }
    
    .category-title {
        font-size: 14px;
    }
    
    .tool-card {
        padding: 14px;
    }
    
    .tool-header {
        gap: 10px;
    }
    
    .tool-icon-wrapper {
        width: 34px;
        height: 34px;
        font-size: 15px;
    }
    
    .tool-name {
        font-size: 14px;
    }
    
    .tool-desc {
        font-size: 11.5px;
        margin-bottom: 10px;
    }
    
    .tool-footer {
        padding-top: 8px;
    }
}