/* ============================================
   AIS Promotion Website - Design System
   สไตล์ชีทกลางที่ใช้ร่วมกันทุกหน้า
   ============================================ */

/* --- CSS Variables: ระบบตัวแปรสี/ฟอนต์ --- */
:root {
  /* สีหลัก AIS */
  --color-primary: #00A950;
  --color-primary-dark: #008a40;
  --color-primary-light: #e6f7ee;

  /* สีตัวอักษร */
  --color-text: #333;
  --color-text-light: #666;
  --color-text-white: #fff;

  /* สีพื้นหลัง */
  --color-bg: #f5f5f5;
  --color-bg-white: #fff;

  /* สีเส้นขอบ */
  --color-border: #e0e0e0;

  /* เงา */
  --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.08);
  --shadow-btn: 0 4px 16px rgba(0, 169, 80, 0.3);

  /* มุมโค้ง */
  --radius: 12px;
  --radius-sm: 8px;

  /* ฟอนต์ */
  --font-family: 'Prompt', sans-serif;

  /* ขนาดฟอนต์ */
  --fs-h1: clamp(1.5rem, 5vw, 2rem);
  --fs-h2: clamp(1.2rem, 4vw, 1.5rem);
  --fs-h3: clamp(1rem, 3vw, 1.2rem);
  --fs-body: clamp(0.95rem, 2.5vw, 1.05rem);
  --fs-small: 0.85rem;

  /* ระยะห่าง */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--fs-body);
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  color: var(--color-primary-dark);
}

/* --- Layout: โครงสร้างหน้าหลัก --- */
.container {
  width: 100%;
  max-width: 680px;
  margin: 0 auto;
  padding: 0 var(--space-sm);
}

/* --- Header: ส่วนหัวเว็บ --- */
.site-header {
  background: var(--color-primary);
  padding: var(--space-sm) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-text-white);
  letter-spacing: -0.5px;
}

.logo span {
  font-weight: 400;
  opacity: 0.9;
}

/* ลิงก์กลับหน้าแรกใน Header */
.header-home-link {
  color: var(--color-text-white);
  font-size: var(--fs-small);
  opacity: 0.9;
  transition: opacity 0.2s;
}

.header-home-link:hover {
  opacity: 1;
  color: var(--color-text-white);
}

/* --- Breadcrumb: เส้นทางนำทาง --- */
.breadcrumb {
  padding: var(--space-xs) 0;
  font-size: var(--fs-small);
  color: var(--color-text-light);
}

.breadcrumb a {
  color: var(--color-text-light);
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb span {
  margin: 0 0.3rem;
}

/* --- Hero Section: ส่วน Above the Fold --- */
.hero-section {
  background: var(--color-bg-white);
  border-radius: 0 0 var(--radius) var(--radius);
  padding: var(--space-md) var(--space-sm) var(--space-lg);
  margin-bottom: var(--space-md);
  box-shadow: var(--shadow-card);
}

.hero-section h1 {
  font-size: var(--fs-h1);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.4;
  margin-bottom: var(--space-sm);
}

.hero-section h1 .highlight {
  color: var(--color-primary);
}

/* รูปภาพ Infographic หลัก */
.hero-image {
  width: 100%;
  border-radius: var(--radius);
  margin: var(--space-sm) 0;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: var(--color-primary-light);
}

/* คำอธิบายสั้นใต้ H1 */
.hero-desc {
  font-size: var(--fs-body);
  color: var(--color-text-light);
  margin-bottom: var(--space-md);
}

/* --- CTA Button: ปุ่มกดโทร --- */
.cta-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-primary);
  color: var(--color-text-white);
  font-family: var(--font-family);
  font-size: 1.15rem;
  font-weight: 700;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  text-align: center;
  box-shadow: var(--shadow-btn);
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
}

.cta-btn:hover {
  background: var(--color-primary-dark);
  color: var(--color-text-white);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 169, 80, 0.4);
}

.cta-btn:active {
  transform: translateY(0);
}

.cta-btn .icon {
  font-size: 1.3rem;
}

/* CTA แบบรอง (Outline) */
.cta-btn--secondary {
  background: var(--color-bg-white);
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
  box-shadow: none;
}

.cta-btn--secondary:hover {
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
}

/* --- Card: การ์ดทั่วไป --- */
.card {
  background: var(--color-bg-white);
  border-radius: var(--radius);
  padding: var(--space-md);
  margin-bottom: var(--space-md);
  box-shadow: var(--shadow-card);
}

.card h2 {
  font-size: var(--fs-h2);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  padding-bottom: var(--space-xs);
  border-bottom: 3px solid var(--color-primary);
}

.card h3 {
  font-size: var(--fs-h3);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

/* --- Video Section: ส่วนวิดีโอ YouTube --- */
.video-wrapper {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%; /* อัตราส่วน 16:9 */
  height: 0;
  overflow: hidden;
  border-radius: var(--radius);
  background: #000;
}

.video-wrapper iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* --- Data Table: ตารางข้อมูล SEO --- */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--fs-body);
}

.data-table th,
.data-table td {
  padding: var(--space-xs) var(--space-sm);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.data-table th {
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
  font-weight: 600;
  white-space: nowrap;
  width: 35%;
}

.data-table td {
  color: var(--color-text);
  font-weight: 500;
}

.data-table tr:last-child th,
.data-table tr:last-child td {
  border-bottom: none;
}

/* ไฮไลท์แถวราคา */
.data-table .highlight-row td {
  color: var(--color-primary);
  font-weight: 700;
  font-size: 1.1rem;
}

/* --- Internal Links: ลิงก์โปรเน็ตแนะนำ --- */
.link-card {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm);
  background: var(--color-primary-light);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-xs);
  transition: background 0.2s, transform 0.15s;
  border: 1px solid transparent;
}

.link-card:hover {
  background: #d0f0de;
  transform: translateX(4px);
  border-color: var(--color-primary);
  color: var(--color-text);
}

.link-card .link-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.link-card .link-info {
  flex: 1;
}

.link-card .link-title {
  font-weight: 600;
  color: var(--color-text);
  font-size: var(--fs-body);
}

.link-card .link-desc {
  font-size: var(--fs-small);
  color: var(--color-text-light);
}

/* --- FAQ Section: ส่วนถาม-ตอบ (ใช้ details/summary) --- */
.faq-item {
  border-bottom: 1px solid var(--color-border);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-item summary {
  padding: var(--space-sm) 0;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-xs);
  transition: color 0.2s;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

/* ลูกศร FAQ */
.faq-item summary::after {
  content: '▸';
  font-size: 1rem;
  color: var(--color-primary);
  transition: transform 0.2s;
  flex-shrink: 0;
}

.faq-item[open] summary::after {
  transform: rotate(90deg);
}

.faq-item summary:hover {
  color: var(--color-primary);
}

.faq-answer {
  padding: 0 0 var(--space-sm);
  color: var(--color-text-light);
  line-height: 1.8;
}

/* --- Footer: ส่วนท้ายเว็บ --- */
.site-footer {
  background: var(--color-text);
  color: var(--color-text-white);
  text-align: center;
  padding: var(--space-lg) var(--space-sm);
  margin-top: var(--space-lg);
  font-size: var(--fs-small);
}

.site-footer a {
  color: var(--color-primary);
}

.site-footer p {
  margin-bottom: var(--space-xs);
  opacity: 0.8;
}

/* --- Category Grid: ตารางหมวดหมู่หน้า Home --- */
.category-grid {
  display: grid;
  gap: var(--space-md);
}

.category-card {
  background: var(--color-bg-white);
  border-radius: var(--radius);
  padding: var(--space-md);
  box-shadow: var(--shadow-card);
  border-left: 4px solid var(--color-primary);
  transition: transform 0.2s, box-shadow 0.2s;
}

.category-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
}

.category-card h2 {
  font-size: var(--fs-h2);
  margin-bottom: var(--space-xs);
  border-bottom: none;
  padding-bottom: 0;
}

.category-card p {
  color: var(--color-text-light);
  margin-bottom: var(--space-sm);
  font-size: var(--fs-small);
}

/* ลิสต์โปรโมชั่นภายในหมวดหมู่ */
.promo-list {
  list-style: none;
}

.promo-list li {
  padding: var(--space-xs) 0;
  border-bottom: 1px solid var(--color-border);
}

.promo-list li:last-child {
  border-bottom: none;
}

.promo-list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 500;
}

.promo-list a::after {
  content: '→';
  color: var(--color-primary);
  font-size: 1.1rem;
  transition: transform 0.2s;
}

.promo-list a:hover::after {
  transform: translateX(4px);
}

/* Badge ป้ายแนะนำ */
.badge {
  display: inline-block;
  background: var(--color-primary);
  color: var(--color-text-white);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  margin-left: 0.5rem;
  vertical-align: middle;
}

.badge--hot {
  background: #e53935;
}

/* --- Utility Classes --- */
.text-center {
  text-align: center;
}

.mt-sm {
  margin-top: var(--space-sm);
}

.mt-md {
  margin-top: var(--space-md);
}

.mb-sm {
  margin-bottom: var(--space-sm);
}

/* --- Print Styles --- */
@media print {
  .site-header,
  .cta-btn,
  .site-footer {
    display: none;
  }

  body {
    background: #fff;
  }

  .card {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}

/* ===== Header Layout (Logo Left, Menu Right) ===== */
.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  padding: 15px 20px; /* เพิ่มระยะห่างซ้าย-ขวา 20px ไม่ให้โลโก้และเมนูชิดขอบจอ */
}

.header-nav {
  display: flex;
  gap: 12px;
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.header-nav::-webkit-scrollbar {
  display: none;
}

.header-nav a {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.8rem; /* ปรับขนาดตัวหนังสือให้เล็กลง */
  padding: 4px 10px; /* ลดความหนาของปุ่มลงให้ดูเพรียวขึ้น */
  border-radius: 20px;
  background-color: #f0f2f5;
  transition: all 0.2s ease;
}

.header-nav a:hover {
  background-color: #82c525;
  color: #ffffff;
}