/* ====== @Import Retro Fonts ====== */
    @import url('https://fonts.googleapis.com/css2?family=Press+Start+2P&family=Silkscreen&family=Pixelify+Sans:wght@400;700&display=swap');

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

    :root {
      --bg-dark: #060913;
      --bg-panel: #0d1222;
      --neon-orange: #ff8800;
      --neon-orange-dim: #8c4b00;
      --neon-green: #39ff14;
      --neon-green-dim: #1e800a;
      --neon-cyan: #00e5ff;
      --neon-cyan-dim: #008ba3;
      --neon-pink: #ff0055;
      --neon-pink-dim: #990033;
      --text-white: #f8fafc;
      --text-gray: #94a3b8;
    }

    body {
      font-family: 'Pixelify Sans', 'Silkscreen', 'Press Start 2P', 'Microsoft YaHei', monospace;
      background: var(--bg-dark);
      color: var(--text-white);
      min-height: 100vh;
      overflow-x: hidden;
      position: relative;
      image-rendering: pixelated;
    }

    /* ====== High-Fidelity CRT Simulator ====== */
    .crt-scanlines {
      position: fixed;
      top: 0; left: 0; width: 100vw; height: 100vh;
      background: linear-gradient(rgba(18, 16, 16, 0) 50%, rgba(0, 0, 0, 0.18) 50%);
      background-size: 100% 6px;
      z-index: 9999;
      pointer-events: none;
    }

    .crt-vignette {
      position: fixed;
      top: 0; left: 0; width: 100vw; height: 100vh;
      background: radial-gradient(circle, rgba(0,0,0,0) 55%, rgba(0,0,0,0.92) 100%);
      z-index: 9998;
      pointer-events: none;
      animation: crt-breathing 0.2s infinite;
    }

    @keyframes crt-breathing {
      0% { opacity: 0.985; }
      50% { opacity: 0.975; }
      100% { opacity: 1.0; }
    }

    /* ====== 8-Bit Grid & Parallax Particles ====== */
    .bg-grid {
      position: fixed;
      top: 0; left: 0; width: 100%; height: 100%;
      z-index: 0;
      background-image: 
        linear-gradient(rgba(255, 255, 255, 0.015) 2px, transparent 2px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.015) 2px, transparent 2px);
      background-size: 32px 32px;
    }

    .pixel-particle {
      position: fixed;
      width: 6px; height: 6px;
      border: 1px solid #000;
      background: var(--neon-cyan);
      pointer-events: none;
      z-index: 0;
      animation: particleFloat linear infinite;
    }

    @keyframes particleFloat {
      0% { transform: translateY(105vh) rotate(0deg); opacity: 0; }
      10% { opacity: 0.8; }
      90% { opacity: 0.8; }
      100% { transform: translateY(-5vh) rotate(360deg); opacity: 0; }
    }

    /* ====== Layout ====== */
    .main-container {
      position: relative;
      z-index: 1;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      max-width: 1000px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* ====== Header ====== */
    .header-bar {
      padding: 24px 0;
      border-bottom: 6px double rgba(255, 255, 255, 0.15);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .header-tag {
      font-weight: 700;
      font-size: 13px;
      color: var(--neon-cyan);
      letter-spacing: 1px;
      text-shadow: 2px 2px 0px #000;
    }

    /* ====== Hero Section ====== */
    .hero {
      padding: 48px 0 24px;
      text-align: center;
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 12px;
      padding: 8px 18px;
      background: #000;
      border: 4px solid rgba(255, 255, 255, 0.15);
      box-shadow: 4px 4px 0px #000;
      font-weight: 700;
      font-size: 12px;
      color: var(--text-gray);
      margin-bottom: 24px;
    }

    .hero-badge .dot {
      width: 8px; height: 8px;
      background: var(--neon-green);
      animation: pulse 1s steps(2, start) infinite;
      box-shadow: 2px 2px 0 #000;
    }

    .hero-title {
      font-family: 'VT323', monospace;
      font-size: clamp(64px, 10vw, 100px);
      line-height: 0.95;
      margin-bottom: 24px;
      image-rendering: pixelated;
    }

    .hero-title .word-code { color: var(--neon-orange); text-shadow: 4px 4px 0px #000; }
    .hero-title .word-and { color: var(--text-white); font-size: 0.75em; margin: 0 8px; text-shadow: 4px 4px 0px #000; }
    .hero-title .word-teach { color: var(--neon-cyan); text-shadow: 4px 4px 0px #000; }

    /* 像素自白对话框 */
    .intro-bubble {
      display: flex;
      align-items: center;
      gap: 20px;
      background: var(--bg-panel);
      border: 4px solid #fff;
      box-shadow: 4px 4px 0px #000;
      max-width: 680px;
      margin: 0 auto 16px;
      padding: 16px 24px;
      text-align: left;
    }

    .bubble-avatar {
      font-size: 32px;
      background: rgba(255, 255, 255, 0.05);
      width: 54px; height: 54px;
      display: flex; align-items: center; justify-content: center;
      border: 4px solid var(--neon-orange);
      box-shadow: 2px 2px 0px #000;
      flex-shrink: 0;
    }

    .bubble-content {
      font-size: 13.5px;
      line-height: 1.6;
      color: var(--text-gray);
      flex: 1;
    }

    .bubble-content strong {
      color: var(--text-white);
    }

    /* ====== Tools Grid ====== */
    .tools-section {
      margin-bottom: 48px;
    }

    .section-label {
      text-align: center;
      font-weight: 800;
      font-size: 15px;
      color: var(--text-gray);
      margin-bottom: 28px;
      letter-spacing: 2px;
      text-shadow: 2px 2px 0px #000;
    }

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

    @media (max-width: 900px) {
      .tools-grid { grid-template-columns: 1fr; gap: 24px; }
    }

    @media (max-width: 480px) {
      .tools-grid { gap: 16px; }
      .tool-card { padding: 20px 16px; }
      .hero-title { font-size: clamp(48px, 12vw, 72px); }
      .intro-bubble { flex-direction: column; text-align: center; gap: 12px; }
      .contact-container { grid-template-columns: 1fr; }
      .form-group input, .form-group textarea { font-size: 16px; }
    }

    /* ====== Card Styling ====== */
    .tool-card {
      background: var(--bg-panel);
      display: flex;
      flex-direction: column;
      padding: 32px 28px;
      text-decoration: none;
      color: inherit;
      position: relative;
      border-radius: 0 !important;
      cursor: pointer;
      transition: all 0.08s steps(2, start);
    }

    .tool-card.flashlog {
      border: 4px solid var(--neon-orange);
      box-shadow: 4px 4px 0px #000, 8px 8px 0px var(--neon-orange-dim);
    }
    .tool-card.flashlog:hover {
      transform: translate(-4px, -4px);
      box-shadow: 8px 8px 0px #000, 12px 12px 0px var(--neon-orange-dim);
      background: #16101c;
    }
    .tool-card.flashlog:active {
      transform: translate(4px, 4px);
      box-shadow: 0px 0px 0px #000;
    }

    .tool-card.pk-king {
      border: 4px solid var(--neon-cyan);
      box-shadow: 4px 4px 0px #000, 8px 8px 0px var(--neon-cyan-dim);
    }
    .tool-card.pk-king:hover {
      transform: translate(-4px, -4px);
      box-shadow: 8px 8px 0px #000, 12px 12px 0px var(--neon-cyan-dim);
      background: #0f1c2b;
    }
    .tool-card.pk-king:active {
      transform: translate(4px, 4px);
      box-shadow: 0px 0px 0px #000;
    }

    .card-header-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 20px;
    }

    .card-icon {
      font-size: 32px;
      filter: drop-shadow(2px 2px 0px #000);
    }

    .card-tag {
      font-weight: 700;
      font-size: 11px;
      padding: 4px 10px;
      border: 4px solid;
      letter-spacing: 0.5px;
      box-shadow: 2px 2px 0px #000;
    }
    .flashlog .card-tag { color: var(--neon-green); border-color: var(--neon-green); background: rgba(57, 255, 20, 0.05); }
    .pk-king .card-tag { color: var(--neon-cyan); border-color: var(--neon-cyan); background: rgba(0, 229, 255, 0.05); }

    .card-title {
      font-weight: 800;
      font-size: 18px;
      margin-bottom: 24px;
      display: flex;
      align-items: center;
      gap: 10px;
      letter-spacing: 0.5px;
      text-shadow: 2px 2px 0px #000;
    }
    .flashlog .card-title { color: var(--neon-orange); }
    .pk-king .card-title { color: var(--neon-cyan); }

    .feature-list {
      list-style: none;
      margin-bottom: 28px;
      display: flex;
      flex-direction: column;
      gap: 14px;
      flex: 1;
    }

    .feature-list li {
      font-size: 13px;
      line-height: 1.5;
      display: flex;
      align-items: flex-start;
      gap: 10px;
    }

    .feature-list li::before {
      content: "■";
      color: var(--neon-orange);
      font-size: 11px;
      flex-shrink: 0;
      margin-top: 3px;
      text-shadow: 1px 1px 0px #000;
    }
    .pk-king .feature-list li::before { color: var(--neon-cyan); }

    .feature-text {
      flex: 1;
      color: var(--text-gray);
    }

    .feature-text strong {
      color: var(--text-white);
    }

    /* Pixel Buttons */
    .retro-btn {
      font-weight: 700;
      font-size: 14px;
      padding: 12px 18px;
      border: 4px solid;
      background: #000;
      cursor: pointer;
      text-align: center;
      width: 100%;
      outline: none;
      border-radius: 0 !important;
      transition: all 0.05s steps(2, start);
      letter-spacing: 1px;
    }
    .flashlog .retro-btn { color: var(--neon-orange); border-color: var(--neon-orange); box-shadow: 4px 4px 0px var(--neon-orange-dim); }
    .flashlog .retro-btn:active { transform: translate(2px, 2px); box-shadow: 2px 2px 0px var(--neon-orange-dim); }
    .pk-king .retro-btn { color: var(--neon-cyan); border-color: var(--neon-cyan); box-shadow: 4px 4px 0px var(--neon-cyan-dim); }
    .pk-king .retro-btn:active { transform: translate(2px, 2px); box-shadow: 2px 2px 0px var(--neon-cyan-dim); }

    /* Hover 像素括号动画 */
    .tool-card:hover .retro-btn::before {
      content: '▶ ';
      animation: blink 0.5s steps(2, start) infinite;
    }
    .tool-card:hover .retro-btn::after {
      content: ' ◀';
      animation: blink 0.5s steps(2, start) infinite;
    }

    @keyframes blink {
      0%, 100% { opacity: 1; }
      50% { opacity: 0; }
    }

    /* ====== Peer Contact Section ====== */
    .contact-section {
      background: var(--bg-panel);
      border: 4px solid var(--neon-pink);
      box-shadow: 4px 4px 0px #000, 8px 8px 0px var(--neon-pink-dim);
      padding: 28px 32px;
      margin-bottom: 60px;
    }

    .contact-title {
      font-weight: 800;
      font-size: 18px;
      color: var(--neon-pink);
      margin-bottom: 16px;
      text-shadow: 2px 2px 0px #000;
      letter-spacing: 0.5px;
    }

    .contact-container {
      display: grid;
      grid-template-columns: 1.5fr 1fr;
      gap: 32px;
    }

    @media (max-width: 768px) {
      .contact-container { grid-template-columns: 1fr; gap: 24px; }
    }

    .contact-info-left {
      line-height: 1.7;
      font-size: 13.5px;
      color: var(--text-gray);
    }
    .contact-info-left strong { color: var(--text-white); }

    .contact-channel-list {
      list-style: none;
      margin-top: 20px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .contact-channel-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 13.5px;
    }

    .contact-channel-list li .badge {
      font-weight: 700;
      font-size: 10px;
      padding: 4px 8px;
      border: 3px solid var(--neon-pink);
      color: var(--neon-pink);
      min-width: 80px;
      text-align: center;
      letter-spacing: 0.5px;
      box-shadow: 2px 2px 0px #000;
    }

    .contact-channel-list li a {
      color: var(--neon-cyan);
      text-decoration: none;
      font-weight: bold;
      font-family: 'VT323', monospace;
      font-size: 20px;
      letter-spacing: 1px;
    }
    .contact-channel-list li a:hover { text-decoration: underline; }

    .contact-right-qr {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      border: 4px dashed rgba(255, 0, 85, 0.25);
      background: rgba(255, 0, 85, 0.02);
      padding: 20px;
      text-align: center;
    }

    .qr-placeholder {
      width: 118px;
      height: 118px;
      background: var(--text-white);
      border: 4px solid var(--neon-pink);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 12px;
      box-shadow: 4px 4px 0px #000;
    }

    /* ====== Modal ====== */
    .retro-modal-overlay {
      position: fixed;
      top: 0; left: 0; width: 100vw; height: 100vh;
      background: rgba(0, 0, 0, 0.9);
      z-index: 10000;
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 20px;
      backdrop-filter: blur(2px);
    }

    .retro-modal-content {
      background: var(--bg-dark);
      border: 4px solid var(--neon-cyan);
      box-shadow: 4px 4px 0px #000, 8px 8px 0px var(--neon-cyan-dim);
      width: 100%;
      max-width: 560px;
      padding: 28px;
      display: flex;
      flex-direction: column;
      gap: 20px;
    }

    .retro-modal-header {
      font-weight: 800;
      font-size: 15px;
      color: var(--neon-pink);
      border-bottom: 4px dashed rgba(255, 255, 255, 0.15);
      padding-bottom: 12px;
      letter-spacing: 1px;
      text-shadow: 2px 2px 0px #000;
    }

    .retro-modal-body {
      font-size: 13px;
      line-height: 1.7;
      color: var(--text-white);
    }

    .pixel-text {
      font-weight: 700;
      font-size: 14px;
      line-height: 1.3;
      letter-spacing: 0.5px;
    }

    .retro-modal-content .retro-btn {
      color: var(--neon-pink);
      border-color: var(--neon-pink);
      box-shadow: 4px 4px 0px var(--neon-pink-dim);
      margin-top: 12px;
    }
    .retro-modal-content .retro-btn:active { transform: translate(2px, 2px); box-shadow: 2px 2px 0px var(--neon-pink-dim); }

    /* ====== Footer ====== */
    .footer {
      text-align: center;
      padding: 28px 0;
      font-size: 11px;
      font-weight: 500;
      color: var(--text-gray);
      border-top: 6px double rgba(255, 255, 255, 0.15);
      margin-top: auto;
      letter-spacing: 1px;
    }

    .footer span {
      color: var(--neon-pink);
      animation: heartbeat 1.2s steps(2, start) infinite;
      display: inline-block;
    }

    @keyframes heartbeat {
      0%, 100% { transform: scale(1); }
      50% { transform: scale(1.2); }
    }

    @keyframes pulse {
      0%, 100% { opacity: 1; }
      50% { opacity: 0.3; }
    }

    /* ====== Header Nav & Buttons ====== */
    .header-nav {
      display: flex;
      gap: 16px;
    }

    .header-btn {
      font-weight: 700;
      font-size: 13px;
      color: var(--neon-cyan);
      text-decoration: none;
      letter-spacing: 1px;
      text-shadow: 2px 2px 0px #000;
      transition: all 0.08s steps(2, start);
    }

    .header-btn.admin-btn {
      color: var(--neon-pink);
    }

    .header-btn:hover {
      color: var(--text-white);
      transform: translateY(-2px);
    }

    /* ====== Guestbook Section ====== */
    .guestbook-section {
      background: var(--bg-panel);
      border: 4px solid var(--neon-green);
      box-shadow: 4px 4px 0px #000, 8px 8px 0px var(--neon-green-dim);
      padding: 28px 32px;
      margin-bottom: 48px;
    }

    .guestbook-title {
      font-weight: 800;
      font-size: 18px;
      color: var(--neon-green);
      margin-bottom: 20px;
      text-shadow: 2px 2px 0px #000;
      letter-spacing: 0.5px;
    }

    .guestbook-container {
      width: 100%;
    }

    .form-row {
      margin-bottom: 20px;
    }

    .form-group {
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .form-group label {
      font-size: 13px;
      font-weight: 700;
      color: var(--text-gray);
      letter-spacing: 0.5px;
    }

    .form-group input, .form-group textarea {
      background: #000;
      border: 4px solid var(--border);
      color: var(--text-white);
      padding: 12px 14px;
      font-family: inherit;
      font-size: 13.5px;
      outline: none;
      border-radius: 0 !important;
      transition: border-color 0.1s;
    }

    .form-group input:focus, .form-group textarea:focus {
      border-color: var(--neon-green);
    }

    .guestbook-section .submit-btn {
      color: var(--neon-green);
      border-color: var(--neon-green);
      box-shadow: 4px 4px 0px var(--neon-green-dim);
      width: auto;
      min-width: 200px;
    }

    .guestbook-section .submit-btn:active {
      transform: translate(2px, 2px);
      box-shadow: 2px 2px 0px var(--neon-green-dim);
    }

    .form-status {
      margin-top: 16px;
      font-size: 13px;
      font-weight: 700;
      padding: 10px;
      border: 4px solid;
      box-shadow: 4px 4px 0px #000;
      text-shadow: 1px 1px 0px #000;
    }

    .form-status.success {
      color: var(--neon-green);
      border-color: var(--neon-green);
      background: rgba(57, 255, 20, 0.05);
    }

    .form-status.error {
      color: var(--neon-pink);
      border-color: var(--neon-pink);
      background: rgba(255, 0, 85, 0.05);
    }