/* =========================================================
   তেলিখাল উচ্চ বিদ্যালয় — Design Tokens
   ========================================================= */

:root {
  color-scheme: light; 

  /* ---- Core Palette ---- */
  --color-navy-deep:     #0E3A5C;  /*  প্রাইমারি, হেডার */
  --color-navy-darker:   #082943;  /*  hover/active শেড */
  --color-sky-blue:      #4FA3D1;  /*  সেকেন্ডারি */
  --color-sky-light:     #DDEEF8;  /*  ব্যাকগ্রাউন্ড টিন্ট */
  --color-amber:         #E8912E;  /* অ্যাকসেন্ট/CTA */
  --color-amber-dark:    #C97418;  /* amber hover */
  --color-paddy-green:   #4C8C6B;  
  --color-limestone:     #F7F5EF;  /*মূল ব্যাকগ্রাউন্ড */
  --color-white:         #FFFFFF;
  --color-ink:           #23303A;  /* মূল টেক্সট রঙ */
  --color-ink-soft:      #55636C;  /* সেকেন্ডারি টেক্সট */
  --color-border:        #E2E1D8;
  --color-danger:        #C0392B;

  /* ---- Typography ---- */
  --font-display: 'Noto Serif Bengali', 'Noto Sans Bengali', sans-serif; /* শিরোনাম  */
  --font-body:    'Noto Sans Bengali', 'Hind Siliguri', sans-serif;      /* মূল লেখা */
  --font-ui:      'Poppins', 'Noto Sans Bengali', sans-serif;            /* সংখ্যা, লেবেল, বাটন */

  --fs-h1: clamp(1.9rem, 1.5rem + 2vw, 3.2rem);
  --fs-h2: clamp(1.5rem, 1.2rem + 1.2vw, 2.3rem);
  --fs-h3: clamp(1.15rem, 1rem + 0.6vw, 1.5rem);
  --fs-body: 1rem;
  --fs-small: 0.875rem;

  /* ---- Spacing / Radius / Shadow ---- */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-sm: 0 2px 8px rgba(14, 58, 92, 0.08);
  --shadow-md: 0 8px 24px rgba(14, 58, 92, 0.12);
  --shadow-lg: 0 16px 40px rgba(14, 58, 92, 0.18);

  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --container-max: 1200px;
}

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

html { scroll-behavior: smooth; }

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

h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--color-navy-deep);
  line-height: 1.3;
  font-weight: 700;
}
h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: 1.25rem;
}

.section { padding-block: clamp(2.5rem, 2rem + 2vw, 5rem); }
.section-title {
  text-align: center;
  margin-bottom: 2rem;
  position: relative;
}
.section-title span {
  display: inline-block;
  padding-bottom: 0.6rem;
  border-bottom: 3px solid var(--color-amber);
}

/* ---- Reusable Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: var(--fs-small);
  padding: 0.7rem 1.4rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
}
.btn-primary {
  background: var(--color-amber);
  color: var(--color-white);
}
.btn-primary:hover { background: var(--color-amber-dark); transform: translateY(-2px); }
.btn-outline {
  background: transparent;
  border: 1.5px solid var(--color-navy-deep);
  color: var(--color-navy-deep);
}
.btn-outline:hover { background: var(--color-navy-deep); color: var(--color-white); }

/* ---- Reduced Motion ---- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ---- Scroll Reveal Utility ---- */
.reveal-on-scroll {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal-on-scroll.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* ---- Focus visibility ---- */
a:focus-visible, button:focus-visible, input:focus-visible {
  outline: 3px solid var(--color-amber);
  outline-offset: 2px;
}