/* ===== Design System: Tools.neuro.ai.kr ===== */

/* --- Color Palette (CSS Variables) --- */
:root {
    --bg-primary: #0f172a;
    --bg-card: #1e293b;
    --bg-card-hover: #263548;
    --bg-input: #0f172a;
    --border-color: #334155;
    --border-focus: #3b82f6;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-green: #22c55e;
    --accent-red: #ef4444;
    --accent-yellow: #eab308;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --radius: 0.75rem;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

/* --- Base / Site Layout (replaces Tailwind) --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}
.site-body {
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
.site-header {
    border-bottom: 1px solid var(--border-color);
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    position: sticky;
    top: 0;
    z-index: 50;
}
.site-header-inner {
    max-width: 72rem;
    margin: 0 auto;
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.site-logo {
    display: flex;
    align-items: baseline;
    gap: 0.25rem;
}
.site-logo-icon {
    font-size: 1.5rem;
    align-self: center;
    margin-right: 0.25rem;
}
.site-logo-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
    transition: color 0.15s;
}
.site-logo-name:hover { color: var(--accent); }
.site-logo-suffix {
    font-size: 0.8rem;
    font-weight: 400;
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.15s;
    position: relative;
    top: 0.04rem;
}
.site-logo-suffix:hover { color: var(--accent); }
.site-nav {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}
.site-main {
    flex: 1;
    max-width: 72rem;
    margin: 0 auto;
    padding: 2rem 1rem;
    width: 100%;
}
.site-footer {
    border-top: 1px solid var(--border-color);
    padding: 1rem 0;
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-muted);
}
.site-footer-inner {
    max-width: 72rem;
    margin: 0 auto;
    padding: 0 1rem;
}

/* --- Hero (Landing Page) --- */
.hero-section {
    text-align: center;
    margin-bottom: 2.5rem;
}
.hero-title {
    font-size: 1.875rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}
.hero-desc {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

/* --- Tools Grid (Landing Page) --- */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(1, 1fr);
    gap: 1rem;
}
@media (min-width: 640px) {
    .tools-grid { grid-template-columns: repeat(2, 1fr); }
    .hero-title { font-size: 2.25rem; }
}
@media (min-width: 1024px) {
    .tools-grid { grid-template-columns: repeat(3, 1fr); }
}
.tool-card-icon {
    font-size: 1.875rem;
    margin-bottom: 0.75rem;
}
.tool-card-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: white;
    transition: color 0.15s;
}
.tool-card:hover .tool-card-title { color: var(--accent); }
.tool-card-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* --- Navigation --- */
.nav-link {
    padding: 0.375rem 0.75rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: all 0.15s;
}
.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-card);
}

/* --- Tool Card (Landing Page) --- */
.tool-card {
    display: block;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    transition: all 0.2s ease;
    text-decoration: none;
}
.tool-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* --- Tool Page Container --- */
.tool-container {
    max-width: 48rem;
    margin: 0 auto;
}
.tool-header {
    margin-bottom: 1.5rem;
}
.tool-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}
.tool-header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* --- Card Panel --- */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
}
.card + .card {
    margin-top: 1rem;
}

/* --- Labels --- */
.label {
    display: block;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

/* --- Inputs & Textareas --- */
.tool-input,
input[type="text"].tool-input,
input[type="url"].tool-input,
input[type="number"].tool-input,
textarea.tool-input,
select.tool-input {
    width: 100%;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.625rem 0.875rem;
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: border-color 0.15s;
    outline: none;
    box-sizing: border-box;
}
.tool-input:focus {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.15);
}
textarea.tool-input {
    resize: vertical;
    font-family: 'SF Mono', 'Fira Code', 'Fira Mono', Menlo, Consolas, monospace;
    font-size: 0.85rem;
    line-height: 1.6;
}

/* --- Output Area --- */
.tool-output {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.875rem;
    min-height: 3rem;
    font-family: 'SF Mono', 'Fira Code', 'Fira Mono', Menlo, Consolas, monospace;
    font-size: 0.85rem;
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: auto;
    white-space: pre-wrap;
    word-break: break-all;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.375rem;
    padding: 0.5rem 1.125rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s;
    border: none;
    outline: none;
    white-space: nowrap;
}
.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}
.btn-primary {
    background: var(--accent);
    color: white;
}
.btn-primary:hover:not(:disabled) {
    background: var(--accent-hover);
}
.btn-secondary {
    background: var(--bg-input);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}
.btn-secondary:hover:not(:disabled) {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}
.copy-btn {
    background: var(--bg-input);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.375rem 0.75rem;
    font-size: 0.8rem;
}
.copy-btn:hover {
    color: var(--accent);
    border-color: var(--accent);
}
.copy-btn.copied {
    color: var(--accent-green);
    border-color: var(--accent-green);
}

/* --- Button Group --- */
.btn-group {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

/* --- Stats / Info Boxes --- */
.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 0.75rem;
}
.stat-box {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.75rem;
    text-align: center;
}
.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
}
.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.125rem;
}

/* --- Toggle / Tabs --- */
.tab-group {
    display: flex;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.25rem;
    gap: 0.25rem;
}
.tab-btn {
    flex: 1;
    padding: 0.5rem 0.75rem;
    border-radius: 0.375rem;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    background: transparent;
    border: none;
    cursor: pointer;
    transition: all 0.15s;
    text-align: center;
}
.tab-btn.active {
    background: var(--accent);
    color: white;
}
.tab-btn:hover:not(.active) {
    color: var(--text-primary);
}

/* --- Checkbox / Options Row --- */
.option-row {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: center;
}
.option-row label {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
    cursor: pointer;
}
.option-row input[type="checkbox"] {
    accent-color: var(--accent);
    width: 1rem;
    height: 1rem;
}
.option-row input[type="range"] {
    accent-color: var(--accent);
}

/* --- Diff Specific --- */
.diff-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}
@media (max-width: 640px) {
    .diff-container {
        grid-template-columns: 1fr;
    }
}
.diff-added {
    background: rgba(34, 197, 94, 0.15);
    color: #86efac;
}
.diff-removed {
    background: rgba(239, 68, 68, 0.15);
    color: #fca5a5;
}

/* --- Markdown Preview --- */
.markdown-body {
    color: var(--text-primary);
    line-height: 1.7;
}
.markdown-body h1, .markdown-body h2, .markdown-body h3 {
    color: var(--text-primary);
    margin-top: 1.25em;
    margin-bottom: 0.5em;
    font-weight: 700;
}
.markdown-body h1 { font-size: 1.75rem; border-bottom: 1px solid var(--border-color); padding-bottom: 0.3em; }
.markdown-body h2 { font-size: 1.375rem; border-bottom: 1px solid var(--border-color); padding-bottom: 0.3em; }
.markdown-body h3 { font-size: 1.125rem; }
.markdown-body p { margin-bottom: 0.75em; }
.markdown-body code {
    background: var(--bg-card);
    padding: 0.15em 0.4em;
    border-radius: 0.25rem;
    font-size: 0.85em;
}
.markdown-body pre {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    overflow-x: auto;
    margin-bottom: 1em;
}
.markdown-body pre code {
    background: none;
    padding: 0;
}
.markdown-body ul, .markdown-body ol {
    padding-left: 1.5em;
    margin-bottom: 0.75em;
}
.markdown-body li { margin-bottom: 0.25em; }
.markdown-body blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 1rem;
    color: var(--text-secondary);
    margin-bottom: 0.75em;
}
.markdown-body a {
    color: var(--accent);
    text-decoration: underline;
}
.markdown-body table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1em;
}
.markdown-body th, .markdown-body td {
    border: 1px solid var(--border-color);
    padding: 0.5rem 0.75rem;
    text-align: left;
}
.markdown-body th {
    background: var(--bg-card);
    font-weight: 600;
}

/* --- Toast Notification --- */
.toast {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.75rem 1.25rem;
    font-size: 0.875rem;
    color: var(--text-primary);
    box-shadow: var(--shadow);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 100;
}
.toast.show {
    transform: translateY(0);
    opacity: 1;
}

/* --- File Drop Zone --- */
.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius);
    padding: 2rem;
    text-align: center;
    color: var(--text-muted);
    transition: all 0.2s;
    cursor: pointer;
}
.drop-zone:hover,
.drop-zone.dragover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(59, 130, 246, 0.05);
}

/* --- Responsive --- */
@media (max-width: 640px) {
    .tool-container {
        padding: 0;
    }
    .stat-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* --- Slider with value display --- */
.range-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}
.range-row input[type="range"] {
    flex: 1;
}
.range-value {
    min-width: 3rem;
    text-align: center;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--accent);
}

/* --- Image preview --- */
.image-preview {
    max-width: 100%;
    max-height: 300px;
    object-fit: contain;
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

/* --- QR Code output --- */
.qr-output {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}
.qr-output canvas,
.qr-output img {
    border-radius: 0.5rem;
    background: white;
    padding: 1rem;
}