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

html, body {
    height: 100%;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: #fafafa;
    color: #1a1a1a;
    scroll-padding-top: 90px;
    letter-spacing: 0.05rem;
}

nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 5%;
    background: rgba(250, 250, 250, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
    z-index: 100;
    justify-content: center;
}

.nav-links {
    display: flex;
    gap: 3rem;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: #1a1a1a;
    font-size: 0.95rem;
    font-weight: 500;
    position: relative;
    transition: color 0.3s ease;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background: #1a1a1a;
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

nav a.active {
  color: #000;
}

.sidebar {
    position: fixed;
    top: 70px;
    width: 200px;
    background: #fafafa;
    border-right: 1px solid rgba(0, 0, 0, 0.08);
    padding: 1rem 2rem 2rem 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    height: calc(100vh - 70px); /* better when top is 70px */
    overflow-y: auto; /* enables vertical scroll */
}

.sidebar-links {
    list-style: none;
}

.sidebar-link {
    transition: all 0.3s ease;
    font-size: 0.5rem;;
}

.sidebar-link:hover {
    color: #000;
    font-weight: 600;
    padding-left: 6px;
    background-color: #d6d5d5;
}

.sidebar-link.active {
    color: #000;
    font-weight: 400;
    padding-left: 6px;
    background-color: #e5e5e5;
}

.sidebar a {
    display: block;
    text-decoration: none;
    color: #504f4f;
    margin-bottom: 15px;
    font-size: 1rem;
    transition: color 0.3s ease;
    padding-bottom: 10px;
}

.sidebar a:active {
    font-weight: 600;
    border-left: 4px solid #000;
    padding-left: 6px;
}

main {
    padding-top: 120px;
    padding-left: 5%;
    padding-right: 5%;
    line-height: 1.6;
    max-width: 1200px;
    margin: 0 auto;
    margin-left: 200px;
    margin-bottom: 100px;
}

.w-list {
    margin-left: 40px;
    margin-top: 15px;
    margin-bottom: 15px;
}

.week-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 40px;
    text-align: center;
}

.week-h1 {
    font-size: 2.5rem;
    margin: 40px 0;
    text-align: center;
}

h1 {
    font-size: 2.2rem;
}

.code-h1 {
    font-size: 2.2rem;
}

.week-h2 {
    font-size: 2rem;
}

h2 {
    font-size: 1.8rem;
    margin: 30px 0;
}

p, ul, ol {
    margin: 15px 15px;
    font-size: 1.2rem;
}

h3 {
    font-size: 1.5rem;
    margin: 30px 0;
}

h4 {
    margin: 10px 0;
}

.link {
    color: #c12626;
    text-decoration: none;
    border-bottom: 2px solid rgba(195, 46, 46, 0.1);
    transition: border-color 0.3s ease;
}

.software-name-heading {
    text-align: center;
}

.project-idea {
    margin: 60px 0;
}

.project-title, .project-description {
    margin: 20px 0;
}

img {
    width: 100%;
    max-width: 700px;
    height: auto;
    border-radius: 8px;
    display: block;
    margin: 40px auto;
}

video {
    max-width: 700px;
    width: 100%;
    height: auto;
    display: block;
    margin: 40px auto;
}

code {
  background-color: #f5f5f5;
  padding: 2px 6px;
  border-radius: 3px;
  font-family: 'Courier New', monospace;
  font-size: 14px;
  color: #d63384;
}

pre {
  background-color: #f5f5f5;
  border: 1px solid #e5e5e5;
  border-radius: 6px;
  padding: 16px;
  margin-bottom: 24px;
  overflow-x: auto;
}

pre code {
  background-color: transparent;
  padding: 0;
  color: #1a1a1a;
}

.no-style {
    list-style: none;
    padding-left: 0;
}

.spec-table {
    width: 100%;
    max-width: 900px;
    margin: 24px auto; /* give it margins */
    border-collapse: collapse;
    background: #ffffff;
    box-shadow: 0 6px 18px rgba(0,0,0,0.06);
    border-radius: 8px;
    overflow: hidden;
}

.spec-table th,
.spec-table td {
    padding: 12px 16px;
    text-align: left;
    vertical-align: top;
}

.spec-table th {
    background: #f7f7f7;
    width: 30%;
    font-weight: 600;
}

.spec-table tr + tr td {
    border-top: 1px solid #f0f0f0;
}

.inner-list {
    list-style-type: disc;
    margin-left: 20px;
}

section {
    margin: 40px 0;
}

.sub-section {
    margin: 20px 0;
}

.figma, .inkscape,.photopea, .fusion, .tinkercad, .blender {
    margin: 40px 0;
}

.small-image {
    height: 100%;
    max-height: 500px;
}

footer {
  font-size: 12px;
  color: #999;
  text-align: center;
  padding: 50px 0 30px 0;
}

footer p, footer a {
  font-size: 12px;
  color: #999;
}

.tabs-container {
    margin: 60px 0;
    border-top: 2px solid #e5e5e5;
    padding-top: 40px;
}

.tabs-header {
    display: flex;
    gap: 0;
    border-bottom: 2px solid #e5e5e5;
    margin-bottom: 0;
}

input[type="radio"] {
    display: none;
}

.tab-label {
    padding: 16px 24px;
    cursor: pointer;
            font-size: 1rem;
            font-weight: 500;
            color: #666;
            border-bottom: 3px solid transparent;
            transition: all 0.3s ease;
            position: relative;
            user-select: none;
        }

        .tab-label:hover {
            color: #1a1a1a;
            background-color: #f5f5f5;
        }

input[type="radio"]:checked + .tab-label {
    color: #1a1a1a;
    border-bottom-color: #1a1a1a;
    background-color: #fafafa;
}

.tab-content {
    display: none;
    padding: 30px;
    background: #fff;
    border-radius: 0 0 8px 8px;
    border: 1px solid #e5e5e5;
    border-top: none;
    animation: fadeIn 0.3s ease-in-out;
}

input[type="radio"]:checked + .tab-label + .tab-content {
    display: block;
}

    @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(-5px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .tab-content h3 {
            margin-top: 0;
        }

        .resource-link {
            display: inline-block;
            margin-top: 15px;
            padding: 12px 24px;
            background: #1a1a1a;
            color: #fff;
            text-decoration: none;
            border-radius: 6px;
            transition: all 0.3s ease;
            font-weight: 500;
            letter-spacing: 0.3px;
        }

        .resource-link:hover {
            background: #333;
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
        }

        a {
            color: #1a1a1a;
            text-decoration: none;
            /* border-bottom: 2px solid rgba(0, 0, 0, 0.1); */
            transition: border-color 0.3s ease;
        }

        a:hover {
            border-bottom-color: #1a1a1a;
        }

        @media (max-width: 1024px) {
            main {
                padding-left: 200px;
                padding-right: 40px;
            }

            .sidebar {
                width: 180px;
            }

            h1 {
                font-size: 2.2rem;
            }

            h2 {
                font-size: 1.7rem;
            }
        }

        @media (max-width: 768px) {
            nav {
                height: 60px;
            }

            .nav-links {
                gap: 1.5rem;
                font-size: 0.9rem;
            }

            .sidebar {
                position: absolute;
                top: 60px;
                left: -180px;
                width: 180px;
                height: auto;
                max-height: 400px;
                box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
            }

            main {
                padding-left: 20px;
                padding-right: 20px;
                padding-top: 80px;
            }

            h1 {
                font-size: 1.8rem;
            }

            h2 {
                font-size: 1.4rem;
            }

            .tabs-header {
                flex-wrap: wrap;
            }

            .tab-label {
                padding: 12px 16px;
                font-size: 0.9rem;
            }
        }

.small-video {
    max-height: 400px;
}