:root {
    --bg: #0f172a;
    --card-bg: #1e293b;
    --card-hover: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent: #3b82f6;
    --border: #334155;
    --radius: 16px;
    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--bg);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 60px 20px;
}

.container {
    max-width: 1100px;
    width: 100%;
}

header {
    text-align: center;
    margin-bottom: 60px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 12px;
}

.logo-icon {
    width: 42px;
    height: 42px;
    color: var(--accent);
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.05em;
}

h1 span {
    color: var(--accent);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

/* Tool Grid */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.tool-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    padding: 32px;
    border-radius: var(--radius);
    text-decoration: none;
    color: inherit;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow);
}

.tool-card:hover {
    transform: translateY(-8px);
    background: var(--card-hover);
    border-color: var(--accent);
}

.icon-box {
    width: 56px;
    height: 56px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    color: var(--color);
    transition: transform 0.3s;
}

.tool-card:hover .icon-box {
    transform: scale(1.1);
    background: rgba(255, 255, 255, 0.1);
}

.icon-box i {
    width: 28px;
    height: 28px;
}

h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    font-weight: 700;
}

.tool-card p {
    color: var(--text-secondary);
    line-height: 1.5;
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.arrow {
    margin-top: auto;
    color: var(--accent);
    opacity: 0;
    transform: translateX(-10px);
    transition: all 0.3s;
}

.tool-card:hover .arrow {
    opacity: 1;
    transform: translateX(0);
}

/* Tool Page Specific Styles (Reusable) */
.tool-page-container {
    max-width: 800px;
    margin: 0 auto;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    text-decoration: none;
    margin-bottom: 32px;
    font-weight: 500;
    transition: color 0.2s;
}

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

.upload-area {
    background: var(--card-bg);
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 60px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
}

.upload-area:hover,
.upload-area.drag-over {
    border-color: var(--accent);
    background: rgba(59, 130, 246, 0.05);
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--accent);
    margin-bottom: 20px;
}

.btn-primary {
    background: var(--accent);
    color: white;
    border: none;
    padding: 12px 32px;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    font-size: 1rem;
    transition: opacity 0.2s;
}

.btn-primary:hover {
    opacity: 0.9;
}

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

/* Footer */
footer {
    text-align: center;
    margin-top: 80px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 900px) {
    .tool-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .tool-grid {
        grid-template-columns: 1fr;
    }

    h1 {
        font-size: 2rem;
    }

    body {
        padding: 40px 16px;
    }
}

/* SEO Content & Guide Sections */
.content-section {
    margin-top: 120px;
    padding-top: 80px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    margin-bottom: 80px;
    position: relative;
    max-width: 1000px;
    margin-left: auto;
    margin-right: auto;
}

/* Gradient Fade Line */
.content-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
    opacity: 0.5;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 32px;
    color: var(--text-primary);
    text-align: center;
    letter-spacing: -0.02em;
}

.text-content {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 60px;
    font-size: 1.1rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    text-align: center;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    margin-top: 40px;
}

.step-card {
    background: linear-gradient(145deg, #1e293b, #0f172a);
    border: 1px solid var(--border);
    padding: 40px 32px;
    border-radius: 24px;
    position: relative;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    z-index: 1;
}

/* Subtle glow effect on hover */
.step-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: 0 15px 30px -10px rgba(59, 130, 246, 0.15);
    border-color: rgba(59, 130, 246, 0.4);
}

.step-number {
    font-size: 5rem;
    font-weight: 900;
    color: transparent;
    -webkit-text-stroke: 2px rgba(255, 255, 255, 0.03);
    position: absolute;
    top: -10px;
    right: 16px;
    line-height: 1;
    font-family: 'Inter', sans-serif;
    transition: all 0.4s ease;
    z-index: 0;
}

.step-card:hover .step-number {
    -webkit-text-stroke-color: rgba(59, 130, 246, 0.1);
    transform: scale(1.1) rotate(5deg);
}

.step-title {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
    position: relative;
    z-index: 2;
}

.step-desc {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.6;
    position: relative;
    z-index: 2;
}

@media (max-width: 600px) {
    .content-section {
        margin-top: 80px;
        padding-top: 40px;
    }

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

    .section-title {
        font-size: 1.75rem;
    }
}