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

body {
    font-family: 'Segoe UI', Roboto, Arial, sans-serif;
    background: #f7f8fa;
    color: #222;
    line-height: 1.6;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.site-header {
    background: #fff;
    border-bottom: 1px solid #e5e7eb;
    position: sticky;
    top: 0;
    z-index: 10;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    color: #4f46e5;
    text-decoration: none;
}

.site-header nav a {
    margin-left: 24px;
    text-decoration: none;
    color: #444;
    font-weight: 500;
}

.site-header nav a:hover {
    color: #4f46e5;
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #4f46e5, #7c3aed);
    color: #fff;
    padding: 60px 0;
    text-align: center;
}

.hero h1 {
    font-size: 36px;
    margin-bottom: 12px;
}

.hero p {
    font-size: 18px;
    opacity: 0.9;
}

/* Tools grid */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    padding: 50px 20px;
}

.tool-card {
    background: #fff;
    border-radius: 12px;
    padding: 30px 20px;
    text-align: center;
    text-decoration: none;
    color: #222;
    box-shadow: 0 1px 3px rgba(0,0,0,0.08);
    transition: transform 0.15s, box-shadow 0.15s;
}

.tool-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(0,0,0,0.1);
}

.tool-card.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.tool-icon {
    font-size: 40px;
    margin-bottom: 12px;
}

.tool-card h3 {
    margin-bottom: 8px;
}

.tool-card p {
    font-size: 14px;
    color: #666;
}

/* Tool page */
.tool-page {
    padding: 50px 20px;
}

.tool-page h1 {
    font-size: 30px;
    margin-bottom: 8px;
}

.tool-subtitle {
    color: #666;
    margin-bottom: 30px;
}

.upload-form {
    max-width: 500px;
    margin-bottom: 40px;
}

.upload-box {
    background: #fff;
    border: 2px dashed #c7c9f5;
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    margin-bottom: 16px;
}

.upload-box input[type="file"] {
    display: none;
}

.upload-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    color: #4f46e5;
    font-weight: 600;
}

.upload-icon {
    font-size: 36px;
    margin-bottom: 10px;
}

.file-list {
    margin-top: 16px;
    text-align: left;
}

.file-item {
    font-size: 14px;
    color: #444;
    padding: 4px 0;
}

.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 8px;
    border: none;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    text-align: center;
}

.btn-primary {
    background: #4f46e5;
    color: #fff;
    width: 100%;
}

.btn-primary:hover {
    background: #4338ca;
}

.btn-download {
    background: #16a34a;
    color: #fff;
    margin-left: 16px;
}

.btn-download:hover {
    background: #15803d;
}

.alert {
    padding: 14px 18px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.alert-error {
    background: #fee2e2;
    color: #b91c1c;
}

.alert-success {
    background: #dcfce7;
    color: #166534;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.how-to {
    background: #fff;
    border-radius: 12px;
    padding: 30px;
    max-width: 700px;
}

.how-to h2 {
    margin-bottom: 16px;
    font-size: 22px;
}

.how-to ol {
    margin-left: 20px;
    margin-bottom: 16px;
}

.how-to li {
    margin-bottom: 8px;
}

/* Footer */
.site-footer {
    background: #1f2937;
    color: #d1d5db;
    text-align: center;
    padding: 30px 20px;
    margin-top: 60px;
}

.site-footer a {
    color: #9ca3af;
    text-decoration: none;
}

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