`;
const footerHTML = ``;
document.getElementById('header-container').innerHTML = headerHTML;
document.getElementById('footer-container').innerHTML = footerHTML;
// catalog logic
let allCourses = [];
let currentPage = 1;
const perPage = 6;
const searchInput = document.getElementById('search');
const categorySelect = document.getElementById('category');
const grid = document.getElementById('product-grid');
const pag = document.getElementById('pagination');
const modal = document.getElementById('detail-modal');
const modalHeader = document.getElementById('modal-header');
const modalContent = document.getElementById('modal-content');
const modalClose = document.getElementById('modal-close');
async function loadCatalog() {
// simulate fetch per spec
const res = await fetch('./catalog.json').catch(()=>null);
if (res && res.ok) {
allCourses = await res.json();
} else {
// fallback embedded 24 courses
allCourses = [
{"id":"c1","title":"Beginner T-Shirt Painting","category":"Beginner","level":"Beginner","duration":"4 weeks","price":245,"currency":"USD","summary":"Master even basic strokes.","description":"Learn foundational painting techniques using vellum templates.","outcomes":["Understand brush control","Create first wearable art"],"materials":["Acrylic paints","Thimble set","Vellum sheets"],"visualColor":"#C9A45C"},
{"id":"c2","title":"Intermediate Stitchwork","category":"Intermediate","level":"Intermediate","duration":"6 weeks","price":390,"currency":"USD","summary":"Refine hand-stitch and color layering.","description":"Focus on intricate stitch patterns over painted surfaces.","outcomes":["Advanced layering","Personal motif design"],"materials":["Needles","Thimble","Heavy vellum"],"visualColor":"#34506D"},
{"id":"c3","title":"Advanced Masterclass","category":"Masterclass","level":"Advanced","duration":"8 weeks","price":720,"currency":"USD","summary":"Create signature collections.","description":"Personal mentorship on professional collections.","outcomes":["Full capsule line","Portfolio development"],"materials":["Premium vellum","Gold thimble","Silk blends"],"visualColor":"#C9A45C"},
{"id":"c4","title":"Color Theory Workshop","category":"Color","level":"All levels","duration":"3 weeks","price":175,"currency":"USD","summary":"Unlock harmonious palettes.","description":"Study pigment interaction between even layers.","outcomes":["Palette creation","Lightfast testing"],"materials":["Color charts","Vellum","Brushes"],"visualColor":"#102B4A"},
{"id":"c5","title":"Thimble Techniques","category":"Technique","level":"Intermediate","duration":"5 weeks","price":265,"currency":"USD","summary":"Precision hand pressure control.","description":"Advanced thimble methods for delicate fabrics.","outcomes":["Stitch accuracy","Ergonomic posture"],"materials":["Custom thimbles","Vellum"],"visualColor":"#C9A45C"},
{"id":"c6","title":"Vellum Transfer Mastery","category":"Transfer","level":"All levels","duration":"2 weeks","price":135,"currency":"USD","summary":"Seamless image transfer.","description":"Vellum based transfer methods.","outcomes":["Clean transfers","Multi-layer build"],"materials":["Vellum pads","Transfer medium"],"visualColor":"#B8C4D1"},
{"id":"c7","title":"Evening Wear Painting","category":"Fashion","level":"Advanced","duration":"7 weeks","price":520,"currency":"USD","summary":"Design evening garments.","description":"Elevated evening wear painting using fine stitch accents.","outcomes":["Full garment piece","Fashion show ready"],"materials":["Fine vellum","Silk","Thimbles"],"visualColor":"#071426"},
{"id":"c8","title":"Kids Creative Stitch","category":"Kids","level":"Beginner","duration":"4 weeks","price":145,"currency":"USD","summary":"Fun first painting experiences.","description":"Child friendly approach incorporating safe stitch and thimble play.","outcomes":["Confidence building","First finished shirt"],"materials":["Non-toxic paints","Plastic thimble","Vellum"],"visualColor":"#34506D"},
{"id":"c9","title":"Portrait Painting Course","category":"Portrait","level":"Intermediate","duration":"6 weeks","price":340,"currency":"USD","summary":"Develop portrait accuracy on cotton.","description":"Capture likenesses with even tone applications.","outcomes":["Lifelike portraits","Skin tone mastery"],"materials":["Portrait vellum","Thimble kit"],"visualColor":"#C9A45C"},
{"id":"c10","title":"Logo & Brand Application","category":"Business","level":"All levels","duration":"3 weeks","price":195,"currency":"USD","summary":"Professional logo placement.","description":"Skillful integration of branding using thimble precision.","outcomes":["Client ready work","Brand consistency"],"materials":["Vellum templates","Transfer sheets"],"visualColor":"#34506D"},
{"id":"c11","title":"Textile Texture Workshop","category":"Texture","level":"Intermediate","duration":"5 weeks","price":295,"currency":"USD","summary":"Surface texture development.","description":"Build rich textures through stitch integration.","outcomes":["Dimensional surfaces","Mixed media results"],"materials":["Textured vellum","Thimbles"],"visualColor":"#0D2340"},
{"id":"c12","title":"Sustainable Dyeing","category":"Sustainability","level":"All levels","duration":"4 weeks","price":225,"currency":"USD","summary":"Botanical palette mastery.","description":"Eco-friendly dyes with vellum stencils.","outcomes":["Low-impact methods","Natural palette range"],"materials":["Botanical extracts","Thimble","Vellum"],"visualColor":"#C9A45C"},
{"id":"c13","title":"Pop Art Shirt Painting","category":"Style","level":"Beginner","duration":"3 weeks","price":165,"currency":"USD","summary":"Bold graphic approaches.","description":"Express modern pop sensibility with clean stitch details.","outcomes":["Graphic fluency","Composition balance"],"materials":["Acrylic set","Vellum","Thimble"],"visualColor":"#34506D"},
{"id":"c14","title":"Couture Finishing","category":"Advanced","level":"Advanced","duration":"9 weeks","price":895,"currency":"USD","summary":"Polished couture methods.","description":"Refine finishes using selective stitch and thimble,"<|eos|>