/* ----- GITHUB DARK (refined) ----- */
      :root {
        --bg-primary: #0d1117;
        --bg-secondary: #161b22;
        --bg-tertiary: #21262d;
        --border-primary: #30363d;
        --border-secondary: #3d444d;
        --fg-default: #f0f6fc;
        --fg-muted: #8b949e;
        --fg-subtle: #6e7681;
        --accent-blue: #2f81f7;
        --accent-green: #3fb950;
        --accent-red: #f85149;
        --btn-bg: #238636;
        --btn-bg-hover: #2ea043;
        --btn-border: rgba(240, 246, 252, 0.1);
        --lang-dot: #f1e05a;
        --radius-md: 6px;
        --radius-lg: 8px;
        --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
          Helvetica, Arial, sans-serif;
        --font-mono: "SF Mono", "Cascadia Code", "Roboto Mono", "Courier New",
          monospace;
      }

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

      body {
        background-color: var(--bg-primary);
        color: var(--fg-default);
        font-family: var(--font-sans);
        line-height: 1.5;
      }

      html {
        scroll-behavior: smooth;
        scroll-padding-top: 72px;
      }

      /* navbar (scroll effect) */
      .navbar {
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 0.6rem 2rem;
        background-color: var(--bg-secondary);
        border-bottom: 1px solid var(--border-primary);
        position: sticky;
        top: 0;
        z-index: 100;
        transition: background-color 0.2s ease, border-color 0.2s ease,
          backdrop-filter 0.2s ease;
      }
      .navbar.scrolled {
        background-color: rgba(22, 27, 34, 0.95);
        backdrop-filter: blur(8px);
        border-bottom-color: var(--border-secondary);
      }

      /* logo image – sadabxlogo.png with better fallback */
      .logo-container {
        display: flex;
        align-items: center;
        text-decoration: none;
      }
      .logo-img {
        height: 40px;
        width: auto;
        display: block;
      }
      .logo-fallback {
        display: none;
        font-weight: bold;
        font-size: 1.5rem;
        color: var(--accent-blue);
        background: var(--bg-tertiary);
        width: 40px;
        height: 40px;
        border-radius: 8px;
        align-items: center;
        justify-content: center;
      }
      .logo-img.error + .logo-fallback,
      .logo-img[style*="display: none"] + .logo-fallback {
        display: flex;
      }

      .nav-links {
        display: flex;
        gap: 2rem;
        list-style: none;
      }
      .nav-links a {
        color: var(--fg-muted);
        text-decoration: none;
        font-weight: 500;
        font-size: 0.95rem;
        transition: color 0.15s;
        padding: 0.4rem 0;
        border-bottom: 2px solid transparent;
      }
      .nav-links a:hover {
        color: var(--fg-default);
        border-bottom-color: var(--accent-blue);
      }

      .hamburger {
        display: none;
        flex-direction: column;
        cursor: pointer;
        gap: 4px;
      }
      .hamburger div {
        width: 22px;
        height: 2px;
        background-color: var(--fg-muted);
        transition: 0.2s;
      }

      /* main layout (sidebar + content) */
      .app-wrapper {
        max-width: 1280px;
        margin: 2rem auto;
        padding: 0 2rem;
        display: grid;
        grid-template-columns: 260px 1fr;
        gap: 2rem;
      }

      /* sidebar */
      .sidebar {
        background-color: var(--bg-secondary);
        border: 1px solid var(--border-primary);
        border-radius: var(--radius-lg);
        padding: 1.2rem 0;
        height: fit-content;
        position: sticky;
        top: 82px;
      }
      .sidebar-header {
        font-size: 0.75rem;
        text-transform: uppercase;
        letter-spacing: 0.5px;
        color: var(--fg-subtle);
        padding: 0 1rem 0.8rem;
        border-bottom: 1px solid var(--border-primary);
        margin-bottom: 0.5rem;
        font-weight: 600;
      }
      .sidebar-actions {
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 0.8rem;
        padding: 0.5rem 1rem;
      }

      .action-btn {
        width: 40px;
        height: 40px;
        display: flex;
        align-items: center;
        justify-content: center;
        background-color: var(--bg-tertiary);
        border: 1px solid var(--border-primary);
        border-radius: var(--radius-md);
        color: var(--fg-muted);
        text-decoration: none;
        transition: all 0.2s ease;
      }

      .action-btn:hover {
        background-color: var(--accent-blue);
        color: white;
        border-color: var(--accent-blue);
        transform: translateX(3px);
      }
      .sidebar-nav {
        list-style: none;
      }
      .sidebar-nav li {
        margin-bottom: 0.2rem;
      }
      .sidebar-nav a {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        padding: 0.5rem 1rem;
        color: var(--fg-muted);
        text-decoration: none;
        font-size: 0.9rem;
        font-weight: 500;
        border-left: 3px solid transparent;
        transition: background-color 0.15s, color 0.15s, border-color 0.15s;
      }
      .sidebar-nav a i {
        width: 1.2rem;
        color: var(--fg-subtle);
        font-size: 1rem;
      }
      .sidebar-nav a:hover {
        background-color: var(--bg-tertiary);
        color: var(--fg-default);
      }
      .sidebar-nav a.active-sidebar {
        background-color: var(--bg-tertiary);
        border-left-color: var(--accent-blue);
        color: var(--fg-default);
        font-weight: 600;
      }
      .sidebar-nav a.active-sidebar i {
        color: var(--fg-default);
      }

      /* main content */
      .main-content {
        min-width: 0;
      }

      /* hero: photo on right, no cube, no social icons */
      .hero-card {
        background: var(--bg-secondary);
        border: 1px solid var(--border-primary);
        border-radius: var(--radius-lg);
        padding: 2rem 2.5rem;
        display: flex;
        flex-wrap: wrap;
        align-items: center;
        justify-content: space-between;
        gap: 2rem;
        margin-bottom: 2rem;
      }
      .hero-text {
        flex: 1 1 300px;
      }
      .hero-text h1 {
        font-size: 2.4rem;
        font-weight: 700;
        letter-spacing: -0.02em;
        color: var(--fg-default);
        line-height: 1.3;
        margin-bottom: 1rem;
      }
      .hero-text h1 span {
        color: var(--accent-blue);
      }
      .hero-text p {
        color: var(--fg-muted);
        margin-bottom: 1.8rem;
        max-width: 500px;
        font-size: 1.05rem;
      }
      /* photo on the right */
      .hero-photo {
        flex: 0 0 160px;
        display: flex;
        justify-content: center;
      }
      .hero-photo img {
        width: 160px;
        height: 160px;
        border-radius: 50%;
        object-fit: cover;
        border: 3px solid var(--bg-tertiary);
        box-shadow: 0 0 0 1px var(--border-primary);
      }

      /* buttons */
      .btn {
        display: inline-flex;
        align-items: center;
        gap: 0.5rem;
        padding: 0.6rem 1.4rem;
        border-radius: var(--radius-md);
        font-weight: 600;
        font-size: 0.9rem;
        text-decoration: none;
        cursor: pointer;
        border: 1px solid var(--border-primary);
        transition: background-color 0.15s, border-color 0.15s;
      }
      .btn-primary {
        background-color: var(--btn-bg);
        color: white;
        border-color: var(--btn-border);
      }
      .btn-primary:hover {
        background-color: var(--btn-bg-hover);
      }
      .btn-outline {
        background-color: transparent;
        color: var(--fg-default);
        border-color: var(--border-primary);
      }
      .btn-outline:hover {
        background-color: var(--bg-tertiary);
        border-color: var(--fg-muted);
      }

      /* section cards */
      .section-card {
        background-color: var(--bg-secondary);
        border: 1px solid var(--border-primary);
        border-radius: var(--radius-lg);
        padding: 2rem 2rem 2.5rem;
        margin-bottom: 2rem;
      }

      .section-title {
        font-size: 1.8rem;
        font-weight: 700;
        letter-spacing: -0.02em;
        color: var(--fg-default);
        margin-bottom: 0.25rem;
      }
      .section-subtitle {
        color: var(--fg-muted);
        font-size: 0.95rem;
        margin-bottom: 2rem;
        padding-left: 0.75rem;
        border-left: 3px solid var(--accent-blue);
      }

      /* repo grid (real-time from github) */
      .repo-grid {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
        gap: 1.5rem;
        margin-top: 1rem;
      }

      .repo-card {
        background-color: var(--bg-primary);
        border: 1px solid var(--border-primary);
        border-radius: var(--radius-lg);
        padding: 1.4rem 1.4rem 1.8rem;
        transition: border-color 0.2s;
        text-decoration: none;
        color: inherit;
        display: flex;
        flex-direction: column;
      }
      .repo-card:hover {
        border-color: var(--border-secondary);
      }
      .repo-header {
        display: flex;
        align-items: center;
        gap: 0.6rem;
        margin-bottom: 0.8rem;
      }
      .repo-header i {
        color: var(--fg-muted);
        font-size: 1rem;
      }
      .repo-header h3 {
        font-size: 1.1rem;
        font-weight: 700;
        color: var(--accent-blue);
      }
      .repo-card p {
        color: var(--fg-muted);
        font-size: 0.9rem;
        margin-bottom: 1.2rem;
        line-height: 1.5;
        flex: 1;
      }
      .repo-stats {
        display: flex;
        gap: 1.2rem;
        color: var(--fg-subtle);
        font-size: 0.8rem;
        align-items: center;
        flex-wrap: wrap;
      }
      .repo-stats span {
        display: flex;
        align-items: center;
        gap: 0.3rem;
      }
      .lang-dot {
        width: 10px;
        height: 10px;
        border-radius: 50%;
        display: inline-block;
      }

      /* contact form */
      .contact-form {
        max-width: 700px;
      }
      .form-row {
        display: flex;
        gap: 1rem;
        margin-bottom: 1rem;
        flex-wrap: wrap;
      }
      .form-group {
        flex: 1 1 200px;
      }
      .form-input,
      .form-textarea {
        width: 100%;
        background-color: var(--bg-primary);
        border: 1px solid var(--border-primary);
        border-radius: var(--radius-md);
        color: var(--fg-default);
        padding: 0.6rem 0.8rem;
        font-size: 0.9rem;
        transition: border 0.15s, box-shadow 0.1s;
      }
      .form-input:focus,
      .form-textarea:focus {
        outline: none;
        border-color: var(--accent-blue);
        box-shadow: 0 0 0 3px rgba(47, 129, 247, 0.2);
      }
      .form-textarea {
        min-height: 100px;
        resize: vertical;
      }
      .form-status {
        margin-top: 1rem;
        font-weight: 500;
      }

      /* footer with social icons above copyright */
      .footer {
        background-color: var(--bg-secondary);
        border-top: 1px solid var(--border-primary);
        padding: 2rem 2rem 1.2rem;
        margin-top: 3rem;
        text-align: center;
      }
      .footer-social {
        display: flex;
        justify-content: center;
        gap: 2rem;
        margin-bottom: 1.5rem;
      }
      .footer-social a {
        color: var(--fg-muted);
        font-size: 1.4rem;
        transition: color 0.2s, transform 0.2s;
      }
      .footer-social a:hover {
        color: var(--accent-blue);
        transform: translateY(-3px);
      }
      .footer-bottom {
        font-size: 0.8rem;
        color: var(--fg-subtle);
        border-top: 1px solid var(--border-primary);
        padding-top: 1.2rem;
      }

      .back-to-top {
        position: fixed;
        bottom: 1.5rem;
        right: 1.5rem;
        background-color: var(--bg-secondary);
        color: var(--fg-muted);
        border: 1px solid var(--border-primary);
        width: 38px;
        height: 38px;
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        opacity: 0;
        visibility: hidden;
        transition: 0.15s;
        text-decoration: none;
      }
      .back-to-top.visible {
        opacity: 1;
        visibility: visible;
      }
      .back-to-top:hover {
        background-color: var(--bg-tertiary);
        color: var(--fg-default);
      }

      .fade-in {
        opacity: 0;
        transform: translateY(16px);
        transition: opacity 0.5s ease, transform 0.5s ease;
      }
      .fade-in.appear {
        opacity: 1;
        transform: translateY(0);
      }

      /* responsive */
      @media (max-width: 900px) {
        .app-wrapper {
          grid-template-columns: 1fr;
          padding: 0 1.5rem;
        }
        .sidebar {
          display: none;
        }
        .hero-card {
          flex-direction: column-reverse;
          text-align: center;
        }
        .hero-text p {
          margin-left: auto;
          margin-right: auto;
        }
      }
      @media (max-width: 768px) {
        .navbar {
          padding: 0.6rem 1.5rem;
        }
        .nav-links {
          display: none;
          position: absolute;
          top: 60px;
          right: 1rem;
          background: var(--bg-secondary);
          flex-direction: column;
          width: 200px;
          padding: 1.2rem;
          border: 1px solid var(--border-primary);
          border-radius: var(--radius-lg);
          gap: 0.8rem;
        }
        .nav-links.active {
          display: flex;
        }
        .hamburger {
          display: flex;
        }
      }