/* ========================================
   CAR RENTAL PLATFORM - BASE STYLES
   Polish Market | Sophisticated & Corporate
   ======================================== */

/* ----------------------------------------
   1. VARIABLES
   ---------------------------------------- */
:root {
  /* Colors - Sophisticated Navy & Steel Palette */
  --color-bg: #FFFFFF;
  --color-bg-alt: #F8FAFC;
  --color-bg-elevated: #FFFFFF;
  
  --color-text: #334155;        /* Steel Gray */
  --color-text-heading: #0F172A; /* Deep Navy */
  --color-text-muted: #64748B;
  --color-text-inverse: #FFFFFF;
  
  --color-primary: #0F172A;     /* Deep Navy */
  --color-primary-hover: #1E293B;
  --color-primary-light: #E2E8F0;
  
  --color-accent: #DC2626;      /* Vibrant Red */
  --color-accent-hover: #B91C1C;
  --color-accent-light: #FEE2E2;
  
  --color-success: #059669;
  --color-success-light: #D1FAE5;
  --color-warning: #D97706;
  --color-warning-light: #FEF3C7;
  --color-danger: #DC2626;
  --color-danger-light: #FEE2E2;
  
  --color-border: #E2E8F0;      /* Soft Silver */
  --color-border-strong: #CBD5E1;
  
  /* Typography - Professional & Polish Character Support */
  --font-sans: 'Inter', 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-heading: var(--font-sans);
  
  --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 */
  --text-6xl: 3.75rem;   /* 60px */
  
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  
  /* Spacing Scale (0-96px) */
  --space-0: 0;
  --space-1: 0.25rem;    /* 4px */
  --space-2: 0.5rem;     /* 8px */
  --space-3: 0.75rem;    /* 12px */
  --space-4: 1rem;       /* 16px */
  --space-5: 1.25rem;    /* 20px */
  --space-6: 1.5rem;     /* 24px */
  --space-8: 2rem;       /* 32px */
  --space-10: 2.5rem;    /* 40px */
  --space-12: 3rem;      /* 48px */
  --space-16: 4rem;      /* 64px */
  --space-20: 5rem;      /* 80px */
  --space-24: 6rem;      /* 96px */
  
  /* Border Radius */
  --radius-sm: 0.25rem;   /* 4px */
  --radius-md: 0.5rem;    /* 8px */
  --radius-lg: 0.75rem;   /* 12px */
  --radius-xl: 1rem;      /* 16px */
  --radius-2xl: 1.5rem;   /* 24px */
  --radius-full: 9999px;
  
  /* Shadows - Refined & Subtle */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --shadow-inner: inset 0 2px 4px 0 rgb(0 0 0 / 0.05);
  
  /* Transitions */
  --duration-fast: 150ms;
  --duration-normal: 200ms;
  --duration-slow: 300ms;
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  
  /* Layout */
  --container-max: 1280px;
  --header-height: 4rem;
}

/* ----------------------------------------
   2. RESET & NORMALIZE
   ---------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

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

body {
  min-height: 100vh;
  line-height: var(--leading-normal);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

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

button {
  cursor: pointer;
  background: none;
  border: none;
}

ul,
ol {
  list-style: none;
}

/* ----------------------------------------
   3. BASE STYLES
   ---------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-tight);
  color: var(--color-text-heading);
  letter-spacing: -0.025em;
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-3xl); }
h4 { font-size: var(--text-2xl); }
h5 { font-size: var(--text-xl); }
h6 { font-size: var(--text-lg); }

@media (max-width: 768px) {
  h1 { font-size: var(--text-4xl); }
  h2 { font-size: var(--text-3xl); }
  h3 { font-size: var(--text-2xl); }
}

p {
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-4);
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-in-out);
}

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

/* ----------------------------------------
   4. UTILITIES
   ---------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

@media (min-width: 640px) {
  .container {
    padding-left: var(--space-6);
    padding-right: var(--space-6);
  }
}

@media (min-width: 1024px) {
  .container {
    padding-left: var(--space-8);
    padding-right: var(--space-8);
  }
}

/* Flex & Grid Helpers */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.items-center {
  align-items: center;
}

.justify-between {
  justify-content: space-between;
}

.gap-4 {
  gap: var(--space-4);
}

.grid {
  display: grid;
}

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

/* ----------------------------------------
   5. COMPONENTS
   ---------------------------------------- */

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  line-height: var(--leading-tight);
  border-radius: var(--radius-lg);
  transition: all var(--duration-normal) var(--ease-in-out);
  border: 1px solid transparent;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.btn--primary:hover:not(:disabled) {
  background-color: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn--accent {
  background-color: var(--color-accent);
  color: var(--color-text-inverse)!important;
}

.btn--accent:hover:not(:disabled) {
  background-color: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn--outline {
  background-color: var(--color-bg);
  border-color: var(--color-border-strong);
  color: var(--color-text-heading);
}

.btn--outline:hover:not(:disabled) {
  background-color: var(--color-bg-alt);
  border-color: var(--color-primary);
}

.btn--ghost {
  background-color: transparent;
  color: var(--color-text);
}

.btn--ghost:hover:not(:disabled) {
  background-color: var(--color-bg-alt);
}

/* Form Inputs */
.input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text-heading);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: border-color var(--duration-fast) var(--ease-in-out),
              box-shadow var(--duration-fast) var(--ease-in-out);
}

.input::placeholder {
  color: var(--color-text-muted);
}

.input:hover {
  border-color: var(--color-border-strong);
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgb(15 23 42 / 0.1);
}

.input:disabled {
  background-color: var(--color-bg-alt);
  cursor: not-allowed;
  opacity: 0.6;
}

/* Cards */
.card {
  background-color: var(--color-bg-elevated);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: transform var(--duration-normal) var(--ease-in-out),
              box-shadow var(--duration-normal) var(--ease-in-out);
}

.card:hover {
  box-shadow: var(--shadow-lg);
}

.card__content {
  padding: var(--space-6);
}

.card__header {
  padding: var(--space-6) var(--space-6) 0;
  margin-bottom: var(--space-4);
}

.card__footer {
  padding: 0 var(--space-6) var(--space-6);
  margin-top: var(--space-4);
}

/* ----------------------------------------
   6. ACCESSIBILITY
   ---------------------------------------- */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: var(--color-text-inverse);
  padding: var(--space-2) var(--space-4);
  z-index: 100;
  transition: top var(--duration-fast);
}

.skip-link:focus {
  top: 0;
}

@media (prefers-contrast: high) {
  :root {
    --color-border: #000000;
    --color-text: #000000;
  }
  
  .btn--primary,
  .btn--accent {
    border: 2px solid currentColor;
  }
}