/* CSS Variables */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #0ea5e9;
    --accent-color: #22c55e;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --background-color: #0f172a;
    --surface-color: #1e293b;
    --surface-light: #334155;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --code-bg: #0d1117;
    --success-bg: rgba(34, 197, 94, 0.1);
    --success-border: #22c55e;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', Roboto, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    font-size: 1.25rem;
    color: var(--text-color);
    text-decoration: none;
}

.logo-icon {
    font-size: 1.5rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 24px;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-color);
}

.btn-github {
    background: var(--surface-color);
    padding: 8px 16px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

/* Language Switch Button */
.lang-switch {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.lang-switch:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

/* Main Content */
.playground-main {
    padding-top: 80px;
    min-height: 100vh;
}

/* Tutorial Progress */
.tutorial-progress {
    background: var(--surface-color);
    padding: 16px 24px;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 64px;
    z-index: 100;
}

.progress-bar {
    height: 4px;
    background: var(--surface-light);
    border-radius: 2px;
    margin-bottom: 16px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    width: 20%;
    transition: width 0.5s ease;
}

.progress-steps {
    display: flex;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.step-btn {
    background: var(--background-color);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s;
}

.step-btn:hover {
    border-color: var(--primary-light);
}

.step-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

.step-btn.completed {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
}

/* Tutorial Container */
.tutorial-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 24px;
}

.tutorial-step {
    display: none;
}

.tutorial-step.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.step-header {
    text-align: center;
    margin-bottom: 32px;
}

.step-header h2 {
    font-size: 2rem;
    margin-bottom: 12px;
}

.step-description {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 700px;
    margin: 0 auto;
}

/* Playground Layout */
.playground-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.playground-layout.full-width {
    grid-template-columns: 1fr;
}

/* Code Editor */
.code-editor-section {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.editor-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background: rgba(0, 0, 0, 0.2);
    border-bottom: 1px solid var(--border-color);
}

.file-name {
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.editor-hint {
    font-size: 0.8rem;
    color: var(--warning-color);
}

.code-editor {
    padding: 20px;
    min-height: 300px;
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    background: var(--code-bg);
    color: var(--text-color);
    white-space: pre-wrap;
    outline: none;
    overflow-x: auto;
}

.code-editor.large {
    min-height: 400px;
}

.code-editor:focus {
    box-shadow: inset 0 0 0 2px var(--primary-color);
}

.editor-actions {
    display: flex;
    gap: 8px;
    padding: 12px 16px;
    background: rgba(0, 0, 0, 0.2);
    border-top: 1px solid var(--border-color);
}

.editor-actions button {
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.btn-hint {
    background: var(--surface-light);
    color: var(--text-color);
}

.btn-hint:hover {
    background: var(--warning-color);
    color: white;
}

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

.btn-check:hover {
    background: #16a34a;
}

.btn-reset {
    background: var(--surface-light);
    color: var(--text-muted);
}

.btn-reset:hover {
    background: var(--error-color);
    color: white;
}

/* Syntax Highlighting */
.keyword { color: #c678dd; }
.type { color: #e5c07b; }
.function { color: #61afef; }
.string { color: #98c379; }
.number { color: #d19a66; }
.comment { color: #5c6370; font-style: italic; }
.attribute { color: #56b6c2; }

/* Visualization Section */
.visualization-section {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
}

.visualization-section h3 {
    margin-bottom: 20px;
    font-size: 1.1rem;
}

/* Interface Preview */
.interface-preview {
    margin-bottom: 20px;
}

.trait-box {
    background: var(--background-color);
    border: 2px solid var(--primary-color);
    border-radius: 12px;
    padding: 20px;
}

.trait-name {
    font-family: 'Fira Code', monospace;
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-light);
    margin-bottom: 16px;
    text-align: center;
}

.methods-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.method-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    background: var(--surface-color);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.method-item.detected {
    border-color: var(--accent-color);
}

.method-item.missing {
    border-color: var(--warning-color);
    opacity: 0.7;
}

.method-icon {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 0.8rem;
}

.method-item.detected .method-icon {
    background: var(--accent-color);
    color: white;
}

.method-item.missing .method-icon {
    background: var(--warning-color);
    color: white;
}

.method-item code {
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
}

/* Server Visualization */
.server-viz {
    margin-bottom: 20px;
}

.server-box {
    background: var(--background-color);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
}

.server-box.ready {
    border-color: var(--accent-color);
}

.server-icon {
    font-size: 3rem;
    margin-bottom: 12px;
}

.server-status {
    color: var(--text-muted);
    margin-bottom: 16px;
}

.server-methods {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.method-status {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--surface-color);
    border-radius: 6px;
    font-size: 0.9rem;
}

.status-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.status-dot.ready {
    background: var(--accent-color);
}

.status-dot.pending {
    background: var(--warning-color);
}

/* Connection Visualization */
.connection-viz {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    padding: 20px;
    background: var(--background-color);
    border-radius: 12px;
    margin-bottom: 20px;
}

.client-box, .server-box-small {
    width: 100px;
    padding: 16px;
    background: var(--surface-color);
    border: 2px solid var(--primary-color);
    border-radius: 12px;
    text-align: center;
}

.box-icon {
    font-size: 2rem;
    margin-bottom: 8px;
}

.box-label {
    font-size: 0.85rem;
    font-weight: 500;
}

.pipe-connection {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.pipe {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: var(--surface-color);
    border-radius: 20px;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.pipe-flow {
    width: 40px;
    height: 3px;
    background: var(--primary-color);
    border-radius: 2px;
    position: relative;
    overflow: hidden;
}

.pipe-flow::after {
    content: '';
    position: absolute;
    width: 10px;
    height: 100%;
    background: white;
    animation: flow 1s linear infinite;
}

.pipe-flow.reverse::after {
    animation: flowReverse 1s linear infinite;
}

@keyframes flow {
    from { left: -10px; }
    to { left: 100%; }
}

@keyframes flowReverse {
    from { left: 100%; }
    to { left: -10px; }
}

/* Hint & Success Boxes */
.hint-box, .success-box {
    padding: 16px;
    border-radius: 8px;
    margin-top: 16px;
}

.hint-box {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid var(--warning-color);
}

.hint-box code {
    display: block;
    margin-top: 8px;
    padding: 8px;
    background: var(--code-bg);
    border-radius: 4px;
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
}

.success-box {
    background: var(--success-bg);
    border: 1px solid var(--success-border);
}

.success-box ul {
    margin-top: 12px;
    margin-left: 20px;
}

.success-box li {
    margin: 4px 0;
    color: var(--text-muted);
}

.hidden {
    display: none !important;
}

/* Step Navigation */
.step-navigation {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.btn-prev, .btn-next, .btn-restart {
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.btn-prev {
    background: var(--surface-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.btn-prev:hover {
    background: var(--surface-light);
}

.btn-next {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.btn-next:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-next:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-restart {
    background: var(--surface-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

/* IPC Simulator */
.ipc-simulator {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
}

.simulator-controls {
    display: flex;
    align-items: center;
    gap: 24px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.simulator-controls h3 {
    margin: 0;
}

.method-selector {
    display: flex;
    align-items: center;
    gap: 8px;
}

.method-selector select {
    padding: 8px 12px;
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-color);
    font-family: 'Fira Code', monospace;
}

.input-fields {
    display: flex;
    gap: 16px;
}

.input-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.input-group label {
    color: var(--text-muted);
    font-family: 'Fira Code', monospace;
}

.input-group input {
    width: 80px;
    padding: 8px 12px;
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-color);
    font-family: 'Fira Code', monospace;
    text-align: center;
}

.btn-send {
    padding: 10px 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-send:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

/* IPC Visualization */
.ipc-visualization {
    display: grid;
    grid-template-columns: 1fr 2fr 1fr;
    gap: 20px;
    margin-bottom: 24px;
    align-items: stretch;
}

.ipc-client, .ipc-server {
    background: var(--background-color);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.ipc-client {
    border-color: var(--secondary-color);
}

.ipc-server {
    border-color: var(--primary-color);
}

.component-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    background: rgba(0, 0, 0, 0.2);
    font-weight: 500;
}

.component-icon {
    font-size: 1.2rem;
}

.component-body {
    padding: 16px;
}

.code-display {
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
    white-space: pre-wrap;
    min-height: 100px;
}

/* IPC Channel */
.ipc-channel {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.channel-label {
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.message-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.request-lane, .response-lane {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--background-color);
    border-radius: 8px;
    position: relative;
    overflow: hidden;
}

.lane-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    white-space: nowrap;
}

.message-packet {
    flex: 1;
    height: 40px;
    background: var(--surface-light);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.message-packet.sending {
    animation: sendPacket 1s ease-out;
}

.message-packet.receiving {
    animation: receivePacket 1s ease-out;
}

@keyframes sendPacket {
    0% {
        background: var(--primary-color);
        transform: translateX(-100%);
    }
    50% {
        transform: translateX(0);
    }
    100% {
        background: var(--surface-light);
        transform: translateX(100%);
    }
}

@keyframes receivePacket {
    0% {
        background: var(--accent-color);
        transform: translateX(100%);
    }
    50% {
        transform: translateX(0);
    }
    100% {
        background: var(--surface-light);
        transform: translateX(-100%);
    }
}

.packet-content {
    font-family: 'Fira Code', monospace;
    font-size: 0.75rem;
    padding: 4px 8px;
    white-space: nowrap;
}

/* Packet Inspector */
.packet-inspector {
    background: var(--background-color);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 24px;
}

.packet-inspector h4 {
    margin-bottom: 16px;
}

.packet-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.packet-section h5 {
    margin-bottom: 12px;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.packet-fields {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.field {
    display: flex;
    justify-content: space-between;
    padding: 8px 12px;
    background: var(--surface-color);
    border-radius: 6px;
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
}

.field-name {
    color: var(--text-muted);
}

.field-value {
    color: var(--primary-light);
}

/* Result Display */
.result-display {
    background: var(--background-color);
    border-radius: 12px;
    padding: 20px;
    text-align: center;
}

.result-display h4 {
    margin-bottom: 12px;
}

.result-value {
    font-family: 'Fira Code', monospace;
    font-size: 1.5rem;
    color: var(--accent-color);
    padding: 20px;
    background: var(--surface-color);
    border-radius: 8px;
}

.result-value.error {
    color: var(--error-color);
}

/* Challenge Section */
.challenge-section {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.challenge-card {
    padding: 24px;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(14, 165, 233, 0.1));
    border-bottom: 1px solid var(--border-color);
}

.challenge-card h3 {
    margin-bottom: 12px;
}

.challenge-card ol {
    margin-left: 20px;
    color: var(--text-muted);
}

.challenge-card code {
    background: var(--code-bg);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Fira Code', monospace;
    font-size: 0.9em;
}

.challenge-result-section {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
}

.challenge-test h3 {
    margin-bottom: 16px;
}

.test-runner {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.test-case {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    background: var(--background-color);
    border-radius: 8px;
}

.test-icon {
    font-size: 1.2rem;
}

.test-case.passed .test-icon::before {
    content: '✅';
}

.test-case.failed .test-icon::before {
    content: '❌';
}

/* Completion Badge */
.completion-badge {
    text-align: center;
    padding: 32px;
    margin-top: 24px;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 16px 32px;
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    border-radius: 50px;
    margin-bottom: 20px;
}

.badge-icon {
    font-size: 2rem;
}

.badge-text {
    font-size: 1.25rem;
    font-weight: 700;
    color: #1f2937;
}

.completion-badge p {
    color: var(--text-muted);
    margin-bottom: 24px;
}

.next-steps {
    text-align: left;
    background: var(--background-color);
    padding: 20px;
    border-radius: 12px;
}

.next-steps h4 {
    margin-bottom: 12px;
}

.next-steps ul {
    list-style: none;
}

.next-steps li {
    padding: 8px 0;
}

.next-steps a {
    color: var(--primary-light);
    text-decoration: none;
}

.next-steps a:hover {
    text-decoration: underline;
}

/* Quick Reference Panel */
.quick-reference {
    position: fixed;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    z-index: 500;
}

.toggle-reference {
    position: absolute;
    left: -40px;
    top: 50%;
    transform: translateY(-50%);
    width: 40px;
    height: 50px;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-right: none;
    border-radius: 8px 0 0 8px;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background 0.2s;
}

.toggle-reference:hover {
    background: var(--surface-light);
}

.reference-content {
    width: 300px;
    max-height: 80vh;
    overflow-y: auto;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-right: none;
    border-radius: 12px 0 0 12px;
    padding: 20px;
    transform: translateX(100%);
    transition: transform 0.3s ease;
}

.quick-reference.open .reference-content {
    transform: translateX(0);
}

.reference-content h3 {
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
}

.reference-section {
    margin-bottom: 20px;
}

.reference-section h4 {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.reference-section pre {
    background: var(--code-bg);
    padding: 12px;
    border-radius: 6px;
    overflow-x: auto;
}

.reference-section code {
    font-family: 'Fira Code', monospace;
    font-size: 0.8rem;
    line-height: 1.5;
}

/* Responsive */
@media (max-width: 1024px) {
    .playground-layout {
        grid-template-columns: 1fr;
    }

    .ipc-visualization {
        grid-template-columns: 1fr;
    }

    .packet-details {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .progress-steps {
        gap: 4px;
    }

    .step-btn {
        padding: 6px 12px;
        font-size: 0.75rem;
    }

    .simulator-controls {
        flex-direction: column;
        align-items: flex-start;
    }

    .nav-links {
        display: none;
    }
}

/* Animations */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}