:root {
--bg-primary: #ffffff;
--bg-secondary: #f8fafc;
--bg-tertiary: #f1f5f9;
--text-primary: #0f172a;
--text-secondary: #475569;
--text-muted: #94a3b8;
--border-color: #e2e8f0;
--accent: #4f46e5;
--accent-hover: #4338ca;
--accent-light: #eef2ff;
--success: #10b981;
--warning: #f59e0b;
--error: #ef4444;
--shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
--shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
--shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
--radius-sm: 6px;
--radius-md: 10px;
--radius-lg: 16px;
--transition: 0.2s ease;
}

[data-theme="dark"] {
--bg-primary: #0f172a;
--bg-secondary: #1e293b;
--bg-tertiary: #334155;
--text-primary: #f8fafc;
--text-secondary: #cbd5e1;
--text-muted: #64748b;
--border-color: #334155;
--accent-light: #1e1b4b;
}

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

html {
scroll-behavior: smooth;
}

body {
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
background: var(--bg-secondary);
color: var(--text-primary);
line-height: 1.6;
transition: background var(--transition), color var(--transition);
}

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

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

.header .container {
display: flex;
align-items: center;
justify-content: space-between;
height: 64px;
}

.logo {
display: flex;
align-items: center;
gap: 10px;
text-decoration: none;
color: var(--text-primary);
font-weight: 700;
font-size: 1.25rem;
}

.nav {
display: flex;
gap: 24px;
}

.nav a {
text-decoration: none;
color: var(--text-secondary);
font-weight: 500;
font-size: 0.9rem;
transition: color var(--transition);
}

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

.theme-toggle {
background: var(--bg-tertiary);
border: none;
width: 40px;
height: 40px;
border-radius: var(--radius-sm);
cursor: pointer;
display: flex;
align-items: center;
justify-content: center;
color: var(--text-secondary);
transition: background var(--transition);
}

.theme-toggle:hover {
background: var(--border-color);
}

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

.hero {
padding: 60px 0;
text-align: center;
background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

.hero h1 {
font-size: 2.5rem;
margin-bottom: 12px;
background: linear-gradient(135deg, var(--accent) 0%, #7c3aed 100%);
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;
background-clip: text;
}

.hero p {
color: var(--text-secondary);
font-size: 1.1rem;
max-width: 500px;
margin: 0 auto 32px;
}

.search-box {
max-width: 400px;
margin: 0 auto;
position: relative;
}

.search-box svg {
position: absolute;
left: 16px;
top: 50%;
transform: translateY(-50%);
color: var(--text-muted);
}

.search-box input {
width: 100%;
padding: 14px 16px 14px 48px;
border: 1px solid var(--border-color);
border-radius: var(--radius-md);
font-size: 1rem;
background: var(--bg-primary);
color: var(--text-primary);
transition: border var(--transition), box-shadow var(--transition);
}

.search-box input:focus {
outline: none;
border-color: var(--accent);
box-shadow: 0 0 0 3px var(--accent-light);
}

.tools-section {
padding: 48px 0;
}

.tools-section h2 {
font-size: 1.5rem;
margin-bottom: 24px;
color: var(--text-primary);
}

.tools-grid {
display: grid;
grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
gap: 20px;
}

.tool-card {
background: var(--bg-primary);
border: 1px solid var(--border-color);
border-radius: var(--radius-md);
padding: 24px;
cursor: pointer;
transition: transform var(--transition), box-shadow var(--transition), border var(--transition);
}

.tool-card:hover {
transform: translateY(-2px);
box-shadow: var(--shadow-md);
border-color: var(--accent);
}

.tool-card.hidden {
display: none;
}

.tool-icon {
width: 48px;
height: 48px;
background: var(--accent-light);
border-radius: var(--radius-sm);
display: flex;
align-items: center;
justify-content: center;
margin-bottom: 16px;
color: var(--accent);
}

.tool-card h3 {
font-size: 1.1rem;
margin-bottom: 8px;
color: var(--text-primary);
}

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

.modal-overlay {
position: fixed;
inset: 0;
background: rgba(0,0,0,0.5);
backdrop-filter: blur(4px);
display: none;
align-items: center;
justify-content: center;
z-index: 1000;
padding: 20px;
}

.modal-overlay.active {
display: flex;
}

.modal {
background: var(--bg-primary);
border-radius: var(--radius-lg);
width: 100%;
max-width: 700px;
max-height: 90vh;
overflow: hidden;
display: flex;
flex-direction: column;
box-shadow: var(--shadow-lg);
}

.modal-header {
display: flex;
align-items: center;
justify-content: space-between;
padding: 20px 24px;
border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
font-size: 1.25rem;
color: var(--text-primary);
}

.modal-close {
background: none;
border: none;
cursor: pointer;
color: var(--text-secondary);
padding: 4px;
display: flex;
transition: color var(--transition);
}

.modal-close:hover {
color: var(--text-primary);
}

.modal-body {
padding: 24px;
overflow-y: auto;
}

.tool-input-group {
margin-bottom: 20px;
}

.tool-input-group label {
display: block;
font-weight: 500;
margin-bottom: 8px;
color: var(--text-primary);
font-size: 0.9rem;
}

.tool-input-group textarea,
.tool-input-group input[type="text"],
.tool-input-group input[type="number"],
.tool-input-group select {
width: 100%;
padding: 12px 16px;
border: 1px solid var(--border-color);
border-radius: var(--radius-sm);
font-size: 0.95rem;
font-family: inherit;
background: var(--bg-primary);
color: var(--text-primary);
transition: border var(--transition), box-shadow var(--transition);
}

.tool-input-group textarea {
min-height: 120px;
resize: vertical;
font-family: 'Consolas', 'Monaco', monospace;
}

.tool-input-group textarea:focus,
.tool-input-group input:focus,
.tool-input-group select:focus {
outline: none;
border-color: var(--accent);
box-shadow: 0 0 0 3px var(--accent-light);
}

.tool-actions {
display: flex;
gap: 12px;
flex-wrap: wrap;
margin-bottom: 20px;
}

.btn {
padding: 10px 20px;
border: none;
border-radius: var(--radius-sm);
font-size: 0.9rem;
font-weight: 500;
cursor: pointer;
display: inline-flex;
align-items: center;
gap: 8px;
transition: background var(--transition), transform var(--transition);
}

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

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

.btn-secondary {
background: var(--bg-tertiary);
color: var(--text-primary);
}

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

.btn:active {
transform: scale(0.98);
}

.output-area {
background: var(--bg-tertiary);
border: 1px solid var(--border-color);
border-radius: var(--radius-sm);
padding: 16px;
font-family: 'Consolas', 'Monaco', monospace;
font-size: 0.9rem;
min-height: 100px;
white-space: pre-wrap;
word-break: break-all;
color: var(--text-primary);
cursor: text;
user-select: text;
transition: border-color var(--transition), box-shadow var(--transition);
}

.output-area:hover {
border-color: var(--accent);
}

.output-area:focus {
outline: none;
border-color: var(--accent);
box-shadow: 0 0 0 3px var(--accent-light);
}

.options-row {
display: flex;
gap: 16px;
flex-wrap: wrap;
margin-bottom: 16px;
}

.option-item {
display: flex;
align-items: center;
gap: 8px;
}

.option-item input[type="checkbox"] {
width: 18px;
height: 18px;
accent-color: var(--accent);
}

.option-item label {
font-size: 0.9rem;
color: var(--text-secondary);
cursor: pointer;
}

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

.range-slider input[type="range"] {
flex: 1;
accent-color: var(--accent);
}

.range-slider span {
min-width: 40px;
text-align: center;
font-weight: 500;
color: var(--text-primary);
}

.copy-feedback {
color: var(--success);
font-size: 0.85rem;
margin-left: 8px;
opacity: 0;
transition: opacity var(--transition);
}

.copy-feedback.show {
opacity: 1;
}

.footer {
padding: 32px 0;
text-align: center;
border-top: 1px solid var(--border-color);
background: var(--bg-primary);
}

.footer p {
color: var(--text-muted);
font-size: 0.9rem;
}

@media (max-width: 768px) {
.nav {
display: none;
}
.hero h1 {
font-size: 1.8rem;
}
.hero p {
font-size: 1rem;
}
.tools-grid {
grid-template-columns: 1fr;
}
.modal {
max-height: 95vh;
}
.tool-actions {
flex-direction: column;
}
.btn {
width: 100%;
justify-content: center;
}
}

.tool-page {
padding: 32px 0 64px;
}

.breadcrumb {
display: flex;
align-items: center;
gap: 8px;
margin-bottom: 24px;
font-size: 0.9rem;
}

.breadcrumb a {
color: var(--text-secondary);
text-decoration: none;
}

.breadcrumb a:hover {
color: var(--accent);
}

.breadcrumb span {
color: var(--text-muted);
}

.tool-content h1 {
font-size: 2rem;
margin-bottom: 12px;
}

.tool-desc {
color: var(--text-secondary);
margin-bottom: 32px;
font-size: 1.05rem;
}

.tool-info {
margin-top: 48px;
padding-top: 32px;
border-top: 1px solid var(--border-color);
}

.tool-info h2 {
font-size: 1.25rem;
margin: 24px 0 12px;
color: var(--text-primary);
}

.tool-info h2:first-child {
margin-top: 0;
}

.tool-info p, .tool-info li {
color: var(--text-secondary);
font-size: 0.95rem;
}

.tool-info ul, .tool-info ol {
margin-left: 24px;
}

.tool-info li {
margin-bottom: 8px;
}

.tool-info kbd {
background: var(--bg-tertiary);
border: 1px solid var(--border-color);
border-radius: 4px;
padding: 2px 6px;
font-family: monospace;
font-size: 0.85rem;
}

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

.option-group {
display: flex;
flex-direction: column;
gap: 6px;
}

.option-group label {
font-size: 0.85rem;
color: var(--text-secondary);
}

.option-group select,
.option-group input {
padding: 8px 12px;
border: 1px solid var(--border-color);
border-radius: var(--radius-sm);
background: var(--bg-primary);
color: var(--text-primary);
font-size: 0.9rem;
}

.stats-grid {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
gap: 16px;
margin-bottom: 24px;
}

.stat-box {
background: var(--bg-tertiary);
border-radius: var(--radius-sm);
padding: 16px;
text-align: center;
}

.stat-value {
display: block;
font-size: 1.5rem;
font-weight: 700;
color: var(--accent);
margin-bottom: 4px;
}

.stat-label {
font-size: 0.8rem;
color: var(--text-secondary);
text-transform: uppercase;
letter-spacing: 0.5px;
}

.status-message {
padding: 12px 16px;
border-radius: var(--radius-sm);
margin-bottom: 16px;
font-size: 0.9rem;
display: none;
}

.status-message.success {
display: block;
background: rgba(16, 185, 129, 0.1);
color: var(--success);
border: 1px solid rgba(16, 185, 129, 0.3);
}

.status-message.error {
display: block;
background: rgba(239, 68, 68, 0.1);
color: var(--error);
border: 1px solid rgba(239, 68, 68, 0.3);
}

.hash-results {
margin-bottom: 24px;
}

.hash-row {
display: flex;
align-items: center;
gap: 12px;
padding: 12px;
background: var(--bg-tertiary);
border-radius: var(--radius-sm);
margin-bottom: 8px;
}

.hash-row label {
min-width: 80px;
font-weight: 600;
font-size: 0.85rem;
color: var(--text-secondary);
}

.hash-value {
flex: 1;
font-family: monospace;
font-size: 0.85rem;
word-break: break-all;
color: var(--text-primary);
}

.hash-long {
font-size: 0.75rem;
}

.btn-icon {
padding: 8px;
background: var(--bg-primary);
border: 1px solid var(--border-color);
}

.ip-display {
background: var(--bg-tertiary);
border-radius: var(--radius-md);
padding: 32px;
text-align: center;
margin-bottom: 24px;
}

.ip-label {
font-size: 0.9rem;
color: var(--text-secondary);
margin-bottom: 8px;
}

.ip-value {
font-size: 2rem;
font-weight: 700;
font-family: monospace;
color: var(--accent);
}

.current-time {
background: var(--bg-tertiary);
padding: 16px;
border-radius: var(--radius-sm);
margin-bottom: 24px;
font-family: monospace;
}

.unit-row {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 16px;
margin-bottom: 16px;
}

.rgb-inputs {
display: flex;
gap: 8px;
}

.rgb-inputs input {
flex: 1;
padding: 10px;
text-align: center;
}

.color-preview-large {
height: 80px;
border-radius: var(--radius-sm);
margin-bottom: 20px;
border: 1px solid var(--border-color);
}

.file-drop {
border: 2px dashed var(--border-color);
border-radius: var(--radius-md);
padding: 48px;
text-align: center;
cursor: pointer;
transition: border-color var(--transition), background var(--transition);
position: relative;
}

.file-drop:hover, .file-drop.dragover {
border-color: var(--accent);
background: var(--accent-light);
}

.file-drop input[type="file"] {
position: absolute;
inset: 0;
opacity: 0;
cursor: pointer;
}

.file-types {
font-size: 0.85rem;
color: var(--text-muted);
margin-top: 8px;
}

.image-preview {
text-align: center;
margin-bottom: 24px;
}

.image-preview img {
max-width: 100%;
max-height: 200px;
border-radius: var(--radius-sm);
}

.md-editor {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
margin-bottom: 20px;
}

.md-input textarea {
height: 400px;
resize: none;
}

.md-preview {
background: var(--bg-primary);
border: 1px solid var(--border-color);
border-radius: var(--radius-sm);
padding: 16px;
height: 400px;
overflow-y: auto;
}

.md-preview h1, .md-preview h2, .md-preview h3 {
margin: 16px 0 8px;
}

.md-preview p {
margin-bottom: 12px;
}

.md-preview code {
background: var(--bg-tertiary);
padding: 2px 6px;
border-radius: 4px;
font-size: 0.9em;
}

.md-preview pre {
background: var(--bg-tertiary);
padding: 12px;
border-radius: var(--radius-sm);
overflow-x: auto;
margin: 12px 0;
}

.md-preview blockquote {
border-left: 3px solid var(--accent);
padding-left: 16px;
color: var(--text-secondary);
margin: 12px 0;
}

.regex-input-wrap {
display: flex;
align-items: center;
gap: 4px;
background: var(--bg-primary);
border: 1px solid var(--border-color);
border-radius: var(--radius-sm);
padding: 4px 12px;
}

.regex-delim {
font-family: monospace;
font-size: 1.2rem;
color: var(--text-muted);
}

.regex-input-wrap input {
flex: 1;
border: none;
background: transparent;
font-family: monospace;
font-size: 1rem;
padding: 8px 4px;
}

.regex-input-wrap input:focus {
outline: none;
}

.regex-flags {
width: 60px !important;
flex: 0 0 60px !important;
text-align: center;
}

.match-item {
padding: 8px 12px;
background: var(--bg-tertiary);
border-radius: var(--radius-sm);
margin-bottom: 8px;
font-size: 0.9rem;
}

.regex-highlighted mark {
background: var(--warning);
color: #000;
padding: 1px 2px;
border-radius: 2px;
}

.diff-added {
background: rgba(16, 185, 129, 0.2);
color: var(--success);
}

.diff-removed {
background: rgba(239, 68, 68, 0.2);
color: var(--error);
text-decoration: line-through;
}

.palette-colors {
display: grid;
grid-template-columns: repeat(5, 1fr);
gap: 12px;
margin-bottom: 24px;
}

.palette-color {
aspect-ratio: 1;
border-radius: var(--radius-sm);
cursor: pointer;
position: relative;
transition: transform var(--transition);
}

.palette-color:hover {
transform: scale(1.05);
}

.palette-color span {
position: absolute;
bottom: 8px;
left: 50%;
transform: translateX(-50%);
background: rgba(0,0,0,0.7);
color: white;
padding: 4px 8px;
border-radius: 4px;
font-size: 0.75rem;
font-family: monospace;
}

@media (max-width: 768px) {
.md-editor {
grid-template-columns: 1fr;
}
.md-input textarea,
.md-preview {
height: 250px;
}
.unit-row {
grid-template-columns: 1fr;
}
.palette-colors {
grid-template-columns: repeat(3, 1fr);
}
}

.password-display {
display: flex;
gap: 12px;
margin-bottom: 16px;
}

.password-field {
flex: 1;
font-family: monospace;
font-size: 1.25rem;
letter-spacing: 1px;
background: var(--bg-tertiary);
}

.strength-bar {
height: 6px;
background: var(--bg-tertiary);
border-radius: 3px;
margin-bottom: 8px;
overflow: hidden;
}

.strength-fill {
height: 100%;
width: 0;
border-radius: 3px;
transition: width 0.3s ease, background 0.3s ease;
}

.strength-text {
font-size: 0.85rem;
text-align: center;
margin-bottom: 20px;
font-weight: 500;
}

.checkbox-grid {
display: grid;
grid-template-columns: repeat(2, 1fr);
gap: 12px;
}

.checkbox-grid label {
display: flex;
align-items: center;
gap: 8px;
cursor: pointer;
font-size: 0.95rem;
}

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

.preset-buttons {
display: flex;
flex-wrap: wrap;
gap: 8px;
margin-top: 8px;
}

.btn-small {
padding: 6px 12px;
font-size: 0.85rem;
}

.btn-large {
padding: 16px 32px;
font-size: 1.1rem;
}

.random-display {
text-align: center;
padding: 32px;
background: var(--bg-tertiary);
border-radius: var(--radius-md);
margin-bottom: 24px;
}

.random-number {
font-size: 3rem;
font-weight: 700;
font-family: monospace;
color: var(--accent);
}

.qr-display {
text-align: center;
padding: 24px;
background: var(--bg-tertiary);
border-radius: var(--radius-md);
margin-bottom: 20px;
min-height: 200px;
display: flex;
align-items: center;
justify-content: center;
}

.qr-placeholder {
color: var(--text-muted);
}

.qr-display img {
max-width: 100%;
border-radius: var(--radius-sm);
}

.output-clickable {
cursor: pointer;
transition: background 0.2s ease;
}

.output-clickable:hover {
background: var(--accent-light);
}

.output-clickable:active {
background: var(--bg-primary);
}

.input-counter {
display: flex;
justify-content: flex-end;
gap: 16px;
font-size: 0.8rem;
color: var(--text-muted);
margin-top: 6px;
font-family: monospace;
}

.input-counter span {
display: inline-flex;
align-items: center;
gap: 4px;
}

@media (max-width: 480px) {
.checkbox-grid {
grid-template-columns: 1fr;
}
.random-number {
font-size: 2rem;
}
.password-field {
font-size: 1rem;
}
}

.shortcuts-hint {
font-size: 0.85rem;
margin-top: 8px;
}

.shortcuts-hint kbd {
background: var(--bg-tertiary);
padding: 2px 6px;
border-radius: 4px;
font-size: 0.8rem;
border: 1px solid var(--border-color);
}

.back-to-top {
position: fixed;
bottom: 24px;
right: 24px;
width: 48px;
height: 48px;
border-radius: 50%;
background: var(--accent);
color: white;
border: none;
cursor: pointer;
display: flex;
align-items: center;
justify-content: center;
box-shadow: var(--shadow-lg);
opacity: 0;
visibility: hidden;
transform: translateY(20px);
transition: opacity 0.3s, visibility 0.3s, transform 0.3s, background 0.2s;
z-index: 90;
}

.back-to-top:hover {
background: var(--accent-hover);
}

.back-to-top.visible {
opacity: 1;
visibility: visible;
transform: translateY(0);
}

.shortcuts-modal {
position: fixed;
top: 0;
left: 0;
right: 0;
bottom: 0;
background: rgba(0, 0, 0, 0.5);
display: flex;
align-items: center;
justify-content: center;
z-index: 200;
opacity: 0;
visibility: hidden;
transition: opacity 0.2s, visibility 0.2s;
}

.shortcuts-modal.active {
opacity: 1;
visibility: visible;
}

.shortcuts-content {
background: var(--bg-primary);
border-radius: var(--radius-lg);
padding: 32px;
max-width: 500px;
width: 90%;
max-height: 90vh;
overflow-y: auto;
position: relative;
box-shadow: var(--shadow-lg);
animation: modalSlide 0.2s ease;
}

@keyframes modalSlide {
from {
transform: translateY(-20px);
opacity: 0;
}
to {
transform: translateY(0);
opacity: 1;
}
}

.shortcuts-close {
position: absolute;
top: 16px;
right: 16px;
width: 32px;
height: 32px;
border: none;
background: var(--bg-tertiary);
border-radius: 50%;
cursor: pointer;
font-size: 1.25rem;
color: var(--text-secondary);
display: flex;
align-items: center;
justify-content: center;
transition: background 0.2s, color 0.2s;
}

.shortcuts-close:hover {
background: var(--error);
color: white;
}

.shortcuts-content h2 {
margin-bottom: 20px;
font-size: 1.5rem;
}

.shortcuts-content h3 {
margin-top: 24px;
margin-bottom: 12px;
font-size: 1.1rem;
color: var(--text-secondary);
}

.shortcuts-grid {
display: grid;
gap: 12px;
}

.shortcut-item {
display: flex;
align-items: center;
gap: 12px;
}

.shortcut-item kbd {
background: var(--bg-tertiary);
padding: 4px 10px;
border-radius: 6px;
font-size: 0.85rem;
border: 1px solid var(--border-color);
font-family: monospace;
min-width: 28px;
text-align: center;
}

.shortcut-item span {
color: var(--text-secondary);
font-size: 0.95rem;
}