/* -------------------------------------------------------
   IEMS5718 Phase 1 (Layout) - Dummy Shopping Website
   - No JavaScript required
   - Semantic HTML + external CSS
-------------------------------------------------------- */

:root{
  --max-width: 1200px;

  --bg: #ffffff;
  --surface: #f9fafb;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;

  --accent: #2563eb;
  --accent-2: #1d4ed8;

  --radius: 14px;
  --shadow: 0 18px 40px rgba(0,0,0,0.12);

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
}

/* Base / Reset */
*{ box-sizing: border-box; }
html, body{ height: 100%; }
body{
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, "Noto Sans", "PingFang HK", "Heiti TC", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.5;
}

img{
  max-width: 100%;
  display: block;
}

a{
  color: inherit;
  text-decoration: none;
}
a:hover{ text-decoration: underline; }

button, input{
  font: inherit;
}

/* Utility */
.container{
  width: min(var(--max-width), calc(100% - 2 * var(--space-6)));
  margin: 0 auto;
}

.sr-only{
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Buttons */
.btn{
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
  border-radius: 999px;
  padding: 0.55rem 0.95rem;
  cursor: pointer;
  user-select: none;
}
.btn:hover{
  border-color: #d1d5db;
  background: #fcfcfd;
}
.btn-primary{
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover{
  background: var(--accent-2);
  border-color: var(--accent-2);
}
.btn-block{ width: 100%; }

/* Header */
.site-header{
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.94);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.header-inner{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-3) 0;
}

.brand{
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-2);
  font-weight: 800;
  letter-spacing: 0.2px;
}
.brand-mark{
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: var(--text);
  color: #fff;
  font-size: 0.95rem;
}

.search{
  flex: 1;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  max-width: 560px;
}
.search input{
  width: 100%;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 999px;
  padding: 0.55rem 0.9rem;
}
.search input:focus{
  outline: 2px solid rgba(37, 99, 235, 0.25);
  border-color: rgba(37, 99, 235, 0.65);
}

/* Cart (Shopping List) - hover on desktop, click (open/close) on mobile */
.cart{
  position: relative;
}

.cart summary{
  list-style: none;
  cursor: pointer;
}
.cart summary::-webkit-details-marker{ display: none; }

.cart-button{
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.55rem 0.9rem;
  background: #fff;
  user-select: none;
  white-space: nowrap;
}
.cart-button:hover{
  border-color: #d1d5db;
  background: #fcfcfd;
}
.cart-pill{
  font-size: 0.82rem;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--muted);
}

.cart-panel{
  display: none;
  position: fixed;
  top: 74px;
  right: max(var(--space-6), calc((100vw - var(--max-width)) / 2));
  width: min(380px, calc(100vw - 2 * var(--space-6)));
  max-height: 72vh;
  overflow: auto;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  z-index: 200;
}

.cart[open] .cart-panel{ display: block; }

/* Hover-to-open for devices that support hover */
@media (hover: hover) and (pointer: fine){
  .cart:not([open]):hover .cart-panel{ display: block; }
}

.cart-panel-header{
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  padding: var(--space-4);
  border-bottom: 1px solid var(--border);
}
.cart-panel h3{
  margin: 0;
  font-size: 1rem;
}
.cart-sub{
  margin: 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.cart-items{
  list-style: none;
  margin: 0;
  padding: var(--space-2) var(--space-4);
  display: grid;
  gap: var(--space-3);
}

.cart-item{
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-3);
  padding: var(--space-3);
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
}
.cart-item-title{
  font-weight: 650;
  margin: 0 0 var(--space-1) 0;
}
.cart-item-meta{
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}
.cart-qty{
  display: grid;
  gap: var(--space-1);
  justify-items: end;
}
.cart-qty label{
  font-size: 0.8rem;
  color: var(--muted);
}
.cart-qty input{
  width: 90px;
  padding: 0.35rem 0.5rem;
  border: 1px solid #d1d5db;
  border-radius: 10px;
}

.cart-panel-footer{
  padding: var(--space-4);
  border-top: 1px solid var(--border);
  display: grid;
  gap: var(--space-3);
}
.cart-total{
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  color: var(--muted);
}
.cart-total strong{
  color: var(--text);
}

/* Layout */
.hero{
  background: linear-gradient(135deg, rgba(37,99,235,0.10), rgba(17,24,39,0.04));
  border-bottom: 1px solid var(--border);
}
.hero-inner{
  padding: var(--space-8) 0 var(--space-6) 0;
}
.hero h1{
  margin: 0 0 var(--space-2) 0;
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  letter-spacing: -0.2px;
}
.hero p{
  margin: 0;
  color: var(--muted);
  max-width: 62ch;
}

.page-grid{
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: var(--space-6);
  padding: var(--space-6) 0 var(--space-8) 0;
}

.sidebar{
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  padding: var(--space-4);
  height: fit-content;
  position: sticky;
  top: 96px;
}

.sidebar h2{
  margin: 0 0 var(--space-3) 0;
  font-size: 1.05rem;
}
.category-nav ul{
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-2);
}
.category-nav a{
  display: block;
  padding: 0.55rem 0.7rem;
  border-radius: 12px;
  border: 1px solid transparent;
}
.category-nav a:hover{
  background: #fff;
  border-color: var(--border);
  text-decoration: none;
}
.sidebar-note{
  margin: var(--space-4) 0 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

/* Product list (CSS tableless) */
.section-title{
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  margin: 0 0 var(--space-3) 0;
}
.section-title h2{
  margin: 0;
  font-size: 1.2rem;
}
.section-title a{
  color: var(--accent);
  font-size: 0.95rem;
}

.product-grid{
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;            /* tableless layout with flexbox */
  flex-wrap: wrap;
  gap: var(--space-4);
}

.product-card{
  flex: 1 1 calc(33.333% - var(--space-4));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  overflow: hidden;
  min-width: 220px;
  display: flex;
  flex-direction: column;
}

.product-thumb{
  display: block;
  border-bottom: 1px solid var(--border);
  background: #fff;
}
.product-thumb img{
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.product-body{
  padding: var(--space-4);
  display: grid;
  gap: var(--space-2);
  flex: 1;
}
.product-name{
  font-weight: 750;
  margin: 0;
}
.product-name a:hover{
  text-decoration: underline;
}
.product-price{
  margin: 0;
  color: var(--muted);
}
.product-actions{
  margin-top: var(--space-2);
}

/* Breadcrumb */
.breadcrumb{
  margin: var(--space-6) 0 var(--space-4) 0;
  color: var(--muted);
  font-size: 0.95rem;
}
.breadcrumb ol{
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.breadcrumb li{
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.breadcrumb li + li::before{
  content: "›";
  color: #9ca3af;
}

/* Product page */
.product-detail{
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-8);
}

.product-media{
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  overflow: hidden;
}
.product-media img{
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.product-info{
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  padding: var(--space-6);
  display: grid;
  gap: var(--space-3);
  height: fit-content;
}
.product-info h1{
  margin: 0;
  font-size: 1.6rem;
}
.product-info p{
  margin: 0;
  color: var(--muted);
}
.product-info .price{
  font-size: 1.35rem;
  color: var(--text);
  font-weight: 800;
}

.product-info .add-row{
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}
.product-info .add-row input{
  width: 120px;
  padding: 0.45rem 0.6rem;
  border: 1px solid #d1d5db;
  border-radius: 12px;
}

/* Footer */
.site-footer{
  border-top: 1px solid var(--border);
  background: var(--surface);
  padding: var(--space-6) 0;
  color: var(--muted);
}
.site-footer p{ margin: 0; }

/* Responsive */
@media (max-width: 920px){
  .page-grid{
    grid-template-columns: 1fr;
  }
  .sidebar{
    position: static;
  }
  .product-card{
    flex: 1 1 calc(50% - var(--space-4));
  }
  .product-detail{
    grid-template-columns: 1fr;
  }
  .cart-panel{
    right: var(--space-6);
  }
}

@media (max-width: 520px){
  .header-inner{
    flex-wrap: wrap;
  }
  .search{
    order: 3;
    width: 100%;
    max-width: none;
  }
  .product-card{
    flex: 1 1 100%;
  }
}

/* -------------------------------------------------------
   Phase 2B / Phase 3 additions
-------------------------------------------------------- */

.category-nav a.active{
  background: #fff;
  border-color: var(--border);
  font-weight: 700;
  text-decoration: none;
}

.btn-small{
  padding: 0.35rem 0.7rem;
  font-size: 0.9rem;
}

.cart-actions{
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  justify-content: flex-end;
}
.cart-remove{
  border-color: #fecaca;
  background: #fff5f5;
}
.cart-remove:hover{
  background: #ffe8e8;
}

.cart-empty{
  padding: var(--space-4);
  color: var(--muted);
  text-align: center;
}

.admin-wrap{
  padding: var(--space-6) 0 var(--space-8) 0;
}

.admin-grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

.admin-card{
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  padding: var(--space-4);
}

.admin-card h2{
  margin-top: 0;
}

.form-grid{
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3);
}

.field{
  display: grid;
  gap: var(--space-1);
}

.field label{
  font-size: 0.9rem;
  color: var(--muted);
}

.field input, .field select, .field textarea{
  border: 1px solid #d1d5db;
  border-radius: 12px;
  padding: 0.55rem 0.7rem;
  background: #fff;
}

.field textarea{
  min-height: 110px;
  resize: vertical;
}

.form-actions{
  margin-top: var(--space-3);
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.table{
  width: 100%;
  border-collapse: collapse;
}

.table th, .table td{
  border-bottom: 1px solid var(--border);
  padding: 0.6rem 0.4rem;
  text-align: left;
  vertical-align: top;
}

.table th{
  color: var(--muted);
  font-weight: 650;
}

.badge{
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.15rem 0.55rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.flash{
  border: 1px solid var(--border);
  background: var(--surface);
  padding: var(--space-3);
  border-radius: 12px;
  margin: var(--space-4) 0;
}

.flash.error{
  border-color: #fecaca;
  background: #fff5f5;
}

@media (max-width: 920px){
  .form-grid{ grid-template-columns: 1fr; }
}

.header-actions{ display:flex; align-items:center; gap: var(--space-2); }

.inline-form{ display:inline-flex; align-items:center; gap: var(--space-2); flex-wrap: wrap; }
.inline-form input, .inline-form select{ min-width: 160px; }

/* -------------------------------------------------------
   Phase 4 security + auth additions
-------------------------------------------------------- */

button, input, select, textarea{
  font: inherit;
}

input, select, textarea{
  width: 100%;
}

input:focus, select:focus, textarea:focus, button:focus-visible, a:focus-visible, summary:focus-visible{
  outline: 2px solid rgba(37, 99, 235, 0.25);
  outline-offset: 1px;
  border-color: rgba(37, 99, 235, 0.65);
}

.page-section{
  padding: var(--space-8) 0;
}

.user-pill{
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.45rem 0.8rem;
  background: #fff;
  color: var(--muted);
  white-space: nowrap;
}

.user-pill strong{
  color: var(--text);
}

.card-list{
  margin: 0;
  padding-left: 1.1rem;
  color: var(--muted);
}

.card-list li + li{
  margin-top: var(--space-2);
}

.field-span-full{
  grid-column: 1 / -1;
}

.field input,
.field select,
.field textarea,
.inline-form input,
.inline-form select{
  width: 100%;
}

.field input,
.field select,
.field textarea{
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.auth-wrap{
  padding: var(--space-6) 0 var(--space-8) 0;
}

.auth-card{
  max-width: 640px;
  margin: 0 auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  padding: var(--space-6);
  display: grid;
  gap: var(--space-4);
}

.auth-card h2{
  margin: 0;
}

.admin-thumb{
  width: 72px;
  height: 72px;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.image-preview-row{
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.preview-thumb{
  width: 140px;
  height: 140px;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.preview-large{
  width: 280px;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.flash.success{
  border-color: #bbf7d0;
  background: #f0fdf4;
}

@media (max-width: 920px){
  .auth-card{
    padding: var(--space-4);
  }
}

@media (max-width: 640px){
  .header-actions{
    width: 100%;
    flex-wrap: wrap;
    justify-content: flex-end;
  }

  .user-pill{
    order: -1;
  }

  .cart-panel{
    top: 120px;
  }

  .inline-form{
    width: 100%;
  }

  .inline-form form{
    width: 100%;
  }
}