/* ===========================
   BASE.CSS - Reset & Variables
   =========================== */

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

:root {
  --red-primary:    #D0021B;
  --red-dark:       #A30015;
  --red-light:      #FF1A33;
  --black-main:     #1A1A1A;
  --black-soft:     #2C2C2C;
  --gray-bg:        #F5F5F5;
  --gray-border:    #E0E0E0;
  --gray-text:      #666666;
  --white:          #FFFFFF;
  --yellow-price:   #D0021B;

  --font-main:      'Roboto', sans-serif;
  --font-size-base: 14px;
  --font-size-sm:   12px;
  --font-size-lg:   16px;
  --font-size-xl:   20px;
  --font-size-xxl:  28px;

  --shadow-card:    0 2px 12px rgba(0,0,0,0.10);
  --shadow-hover:   0 6px 24px rgba(208,2,27,0.18);
  --radius-card:    8px;
  --radius-btn:     4px;

  --transition:     all 0.25s ease;
  --container-max:  1240px;
}

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-main);
  background-color: var(--white);
  color: var(--black-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

ul, ol {
  list-style: none;
}

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

button {
  cursor: pointer;
  border: none;
  outline: none;
  font-family: var(--font-main);
  transition: var(--transition);
}

/* ===========================
   UTILITY CLASSES
   =========================== */
.hidden        { display: none !important; }
.flex          { display: flex; }
.flex-center   { display: flex; align-items: center; justify-content: center; }
.flex-between  { display: flex; align-items: center; justify-content: space-between; }
.text-red      { color: var(--red-primary); }
.text-bold     { font-weight: 700; }
.text-upper    { text-transform: uppercase; }

/* Nut chinh */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 18px;
  border-radius: var(--radius-btn);
  font-weight: 700;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: var(--transition);
}

.btn-red {
  background: var(--red-primary);
  color: var(--white);
}

.btn-red:hover {
  background: var(--red-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-hover);
}

.btn-outline {
  background: transparent;
  color: var(--red-primary);
  border: 2px solid var(--red-primary);
}

.btn-outline:hover {
  background: var(--red-primary);
  color: var(--white);
}

.btn-gray {
  background: var(--gray-bg);
  color: var(--black-main);
  border: 1px solid var(--gray-border);
}

.btn-gray:hover {
  background: var(--gray-border);
}