/* ===========================
   APLEXCUB STUDENT TOOLS
   main.css — Design System
   =========================== */

/* --- Google Fonts Import --- */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&family=Inter:wght@400;500;600&display=swap');

/* --- CSS Variables (Tokens) --- */
:root {
  /* Colors */
  --color-primary:     #2563EB;
  --color-secondary:   #3B82F6;
  --color-accent:      #06B6D4;
  --color-bg:          #FFFFFF;
  --color-surface:     #F8FAFC;
  --color-surface-2:   #F1F5F9;
  --color-text:        #111827;
  --color-text-muted:  #6B7280;
  --color-border:      #E2E8F0;
  --color-shadow:      rgba(37, 99, 235, 0.08);

  /* Typography */
  --font-primary:   'Poppins', sans-serif;
  --font-secondary: 'Inter', sans-serif;

  /* Type Scale */
  --text-xs:   0.75rem;    /* 12px */
  --text-sm:   0.875rem;   /* 14px */
  --text-base: 1rem;       /* 16px */
  --text-lg:   1.125rem;   /* 18px */
  --text-xl:   1.25rem;    /* 20px */
  --text-2xl:  1.5rem;     /* 24px */
  --text-3xl:  1.875rem;   /* 30px */
  --text-4xl:  2.25rem;    /* 36px */
  --text-5xl:  3rem;       /* 48px */

  /* Spacing Scale */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Radius */
  --radius-sm:   8px;
  --radius-md:   12px;
  --radius-lg:   16px;
  --radius-xl:   20px;
  --radius-2xl:  24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm:  0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md:  0 4px 16px rgba(37, 99, 235, 0.08), 0 1px 4px rgba(0,0,0,0.04);
  --shadow-lg:  0 8px 32px rgba(37, 99, 235, 0.12), 0 2px 8px rgba(0,0,0,0.06);
  --shadow-hover: 0 12px 40px rgba(37, 99, 235, 0.18);

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;

  /* Layout */
  --container-max: 1200px;
  --container-pad: 1rem;
  --header-height: 64px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-secondary);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

a:hover { color: var(--color-secondary); }

ul { list-style: none; }

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font-family: inherit;
}

/* --- Typography Classes --- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-primary);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text);
}

.text-gradient {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* --- Container --- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

/* --- Section --- */
.section {
  padding: var(--space-16) 0;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-8);
  gap: var(--space-4);
}

.section-title {
  font-size: var(--text-2xl);
  font-weight: 700;
}

.section-desc {
  color: var(--color-text-muted);
  font-size: var(--text-base);
  margin-top: var(--space-2);
}

.section-link {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-primary);
  white-space: nowrap;
}

/* --- Responsive --- */
@media (max-width: 767px) {
  :root {
    --container-pad: 1rem;
  }
  .section { padding: var(--space-12) 0; }
  .section-title { font-size: var(--text-xl); }
}

@media (min-width: 768px) {
  :root {
    --container-pad: 1.5rem;
  }
}

@media (min-width: 1280px) {
  :root {
    --container-pad: 2rem;
  }
}