/* ============================================
   FONT IMPORTS
   ============================================ */

/* Import Google Fonts - Optimized with font-display:swap */
@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;600&family=IBM+Plex+Mono:wght@400;500&display=swap");
@import url("https://fonts.googleapis.com/css2?family=BBH+Sans+Bogle&display=swap");

/* ============================================
   CSS RESET & BASE STYLES
   ============================================ */

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

html {
  /* Improve text rendering */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans",
    "Helvetica Neue", sans-serif;
  overflow-x: hidden;
}

/* Custom selection color for brand consistency */
::selection {
  background-color: var(--color-primary);
  color: var(--color-neutral-900);
}

/* ============================================
   DESIGN TOKENS - CSS CUSTOM PROPERTIES
   ============================================ */

:root {
  /* Color System - Brand */
  --color-primary: #7aff9b;
  --color-primary-dark: #5fe67f;
  --color-primary-light: #a0ffc0;
  --color-primary-alpha-15: rgba(122, 255, 155, 0.15);
  --color-primary-alpha-90: rgba(122, 255, 155, 0.9);

  /* Color System - Neutral */
  --color-neutral-900: #000000;
  --color-neutral-100: #ffffff;
  --color-neutral-700: rgba(255, 255, 255, 0.7);
  --color-neutral-600: rgba(255, 255, 255, 0.6);

  /* Color System - Semantic */
  --color-success: #7aff9b;
  --color-error: #ff6b6b;
  --color-warning: #ffd93d;
  --color-info: #4dabf7;

  /* Color System - Surface */
  --color-surface-overlay: rgba(0, 0, 0, 0.2);
  --color-surface-form: rgba(122, 255, 155, 0.15);

  /* Spacing Scale (0.25rem increments) */
  --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 */
  --space-32: 8rem; /* 128px */
  --space-48: 12rem; /* 192px */

  /* Typography Scale - Fluid Typography */
  --font-size-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --font-size-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem);
  --font-size-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --font-size-lg: clamp(1.125rem, 1.05rem + 0.375vw, 1.25rem);
  --font-size-xl: clamp(1.25rem, 1.15rem + 0.5vw, 1.5rem);
  --font-size-2xl: clamp(1.5rem, 1.3rem + 1vw, 2rem);
  --font-size-3xl: clamp(1.875rem, 1.5rem + 1.875vw, 2.5rem);
  --font-size-4xl: clamp(2.25rem, 1.75rem + 2.5vw, 3.75rem);
  --font-size-5xl: clamp(3rem, 2rem + 5vw, 4.5rem);
  --font-size-6xl: clamp(3.75rem, 2.5rem + 6.25vw, 6rem);

  /* Font Families */
  --font-family-sans: "IBM Plex Sans", -apple-system, BlinkMacSystemFont,
    "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans",
    "Droid Sans", "Helvetica Neue", sans-serif;
  --font-family-mono: "IBM Plex Mono", "SF Mono", Monaco, "Cascadia Code",
    "Roboto Mono", Consolas, "Courier New", monospace;
  --font-family-display: "BBH Sans Bogle", var(--font-family-sans);

  /* Font Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Line Heights (unitless for better scaling) */
  --line-height-tight: 1.1;
  --line-height-snug: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --line-height-loose: 2;

  /* Letter Spacing */
  --letter-spacing-tight: -0.025em;
  --letter-spacing-normal: 0;
  --letter-spacing-wide: 0.025em;
  --letter-spacing-wider: 0.05em;

  /* Border Radius Scale */
  --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;

  /* Border Widths */
  --border-width-thin: 1px;
  --border-width-base: 2px;
  --border-width-thick: 4px;

  /* Shadow System - Elevation Levels */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1),
    0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1),
    0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1),
    0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-focus: 0 0 0 3px var(--color-primary-alpha-15);

  /* Z-Index Scale */
  --z-index-base: 0;
  --z-index-dropdown: 1000;
  --z-index-sticky: 1020;
  --z-index-fixed: 1030;
  --z-index-modal-backdrop: 1040;
  --z-index-modal: 1050;
  --z-index-popover: 1060;
  --z-index-tooltip: 1070;

  /* Transition Tokens */
  --transition-duration-fast: 150ms;
  --transition-duration-base: 200ms;
  --transition-duration-slow: 300ms;
  --transition-duration-slower: 500ms;

  --transition-timing-ease: ease;
  --transition-timing-ease-in: ease-in;
  --transition-timing-ease-out: ease-out;
  --transition-timing-ease-in-out: ease-in-out;

  /* Breakpoints (for reference in comments) */
  --breakpoint-sm: 480px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;

  /* Max Widths */
  --max-width-xs: 20rem; /* 320px */
  --max-width-sm: 24rem; /* 384px */
  --max-width-md: 28rem; /* 448px */
  --max-width-lg: 32rem; /* 512px */
  --max-width-xl: 36rem; /* 576px */
  --max-width-2xl: 42rem; /* 672px */
  --max-width-3xl: 48rem; /* 768px */
  --max-width-4xl: 56rem; /* 896px */
  --max-width-5xl: 64rem; /* 1024px */
  --max-width-full: 100%;
}

/* ============================================
   UTILITY CLASSES
   ============================================ */

/* Accessibility - Visually hidden but screen reader accessible */
.visually-hidden {
  position: absolute;
  inline-size: 1px;
  block-size: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ============================================
   LAYOUT COMPONENTS
   ============================================ */

/* Page Container */
.page {
  position: relative;
  min-block-size: 100dvh; /* Dynamic viewport height for better mobile support */
  inline-size: 100%;
  overflow: hidden;
  background-color: var(--color-neutral-900);
}

/* Background Image Layer */
.page__background {
  position: fixed;
  inset: 0;
  z-index: var(--z-index-base);
  block-size: 100dvh;
  inline-size: 100vw;
  background-image: url("assets/background.jpg");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

/* Background Overlay */
.page__overlay {
  position: fixed;
  inset: 0;
  z-index: var(--z-index-base);
  block-size: 100dvh;
  inline-size: 100vw;
  background-color: var(--color-surface-overlay);
}

/* Content Container */
.page__content {
  position: relative;
  z-index: var(--z-index-dropdown);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-8);
  inline-size: 100%;
  max-inline-size: var(--max-width-4xl);
  margin-block-start: var(--space-32);
  margin-inline: auto;
  padding-block: var(--space-12);
  padding-inline: var(--space-8);
  text-align: center;
}

/* ============================================
   COMPONENT - LOGO
   ============================================ */

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.logo__icon {
  block-size: var(--space-10);
  inline-size: var(--space-10);
  color: var(--color-primary);
}

.logo__text {
  block-size: var(--space-8);
  inline-size: auto;
}

/* ============================================
   COMPONENT - HEADING
   ============================================ */

.heading {
  color: var(--color-neutral-100);
  font-family: var(--font-family-display);
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-normal);
  letter-spacing: var(--letter-spacing-wide);
  line-height: var(--line-height-tight);
  word-wrap: break-word;
  margin: 0;
  padding: 0;
}

/* ============================================
   COMPONENT - SUBHEADING
   ============================================ */

.subheading {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-lg);
  color: var(--color-neutral-100);
  line-height: var(--line-height-normal);
}

/* ============================================
   COMPONENT - FORM
   ============================================ */

.form {
  display: flex;
  inline-size: 100%;
  max-inline-size: var(--max-width-md);
  padding: var(--space-2);
  margin-block-start: var(--space-4);
  border-radius: var(--radius-md);
  border: var(--border-width-base) solid var(--color-primary);
  background-color: var(--color-surface-form);
}

.form__inner {
  display: flex;
  flex: 1;
  align-items: center;
  gap: var(--space-2);
}

.form__input {
  flex: 1;
  min-inline-size: 0;
  border: 0;
  background: transparent;
  padding-block: var(--space-2);
  padding-inline: var(--space-3);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  color: var(--color-neutral-100);
  outline: none;
  line-height: var(--line-height-normal);
}

.form__input::placeholder {
  color: var(--color-neutral-700);
  font-size: var(--font-size-sm);
}

.form__input:focus {
  outline: none;
}

/* Better focus indicator for keyboard navigation */
.form__input:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================
   COMPONENT - BUTTON
   ============================================ */

.button {
  flex-shrink: 0;
  min-inline-size: fit-content;
  padding-block: var(--space-2);
  padding-inline: var(--space-4);
  background-color: var(--color-primary);
  color: var(--color-neutral-900);
  border: none;
  border-radius: var(--radius-sm);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--transition-duration-base)
    var(--transition-timing-ease-in-out);
}

.button:hover:not(:disabled) {
  background-color: var(--color-primary-alpha-90);
}

.button:active:not(:disabled) {
  background-color: var(--color-primary-dark);
  transform: translateY(1px);
}

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

.button:disabled {
  opacity: 0.8;
  cursor: not-allowed;
}

/* Loading state */
.button--loading {
  position: relative;
  pointer-events: none;
  color: transparent;
}

.button--loading::after {
  content: "";
  position: absolute;
  inset-inline-start: 50%;
  inset-block-start: 50%;
  transform: translate(-50%, -50%);
  inline-size: 1rem;
  block-size: 1rem;
  border: 2px solid var(--color-neutral-900);
  border-top-color: transparent;
  border-radius: 50%;
  animation: button-spinner 0.6s linear infinite;
}

@keyframes button-spinner {
  to {
    transform: translate(-50%, -50%) rotate(360deg);
  }
}

@media (min-width: 768px) {
  .button--loading::after {
    inline-size: 1.125rem;
    block-size: 1.125rem;
  }
}

/* ============================================
   COMPONENT - MESSAGE
   ============================================ */

.message {
  inline-size: 100%;
  max-inline-size: var(--max-width-md);
  margin-block-start: var(--space-2);
  padding: var(--space-2);
  font-size: var(--font-size-sm);
  text-align: center;
  min-block-size: var(--space-6);
  line-height: var(--line-height-normal);
}

.message--success {
  color: var(--color-success);
}

.message--error {
  color: var(--color-error);
}

.message--warning {
  color: var(--color-warning);
}

.message--info {
  color: var(--color-info);
}

/* ============================================
   RESPONSIVE DESIGN - MOBILE FIRST
   ============================================ */

/* Small devices (480px and up) */
@media (min-width: 480px) {
  .logo {
    gap: var(--space-5);
  }

  .logo__icon {
    block-size: var(--space-12);
    inline-size: var(--space-12);
  }

  .logo__text {
    block-size: var(--space-10);
  }

  .heading {
    font-size: var(--font-size-5xl);
    letter-spacing: var(--letter-spacing-wider);
  }
}

/* Medium devices (768px and up) */
@media (min-width: 768px) {
  .page__content {
    margin-block-start: var(--space-48);
    padding-block: var(--space-12);
    padding-inline: var(--space-12);
    gap: var(--space-8);
  }

  .logo {
    gap: var(--space-6);
  }

  .logo__icon {
    block-size: 3.5rem;
    inline-size: 3.5rem;
  }

  .logo__text {
    block-size: var(--space-10);
  }

  .heading {
    font-size: var(--font-size-6xl);
  }

  .subheading {
    font-size: var(--font-size-xl);
  }
}

/* Large devices (1024px and up) */
@media (min-width: 1024px) {
  .page__content {
    padding-inline: var(--space-16);
  }

  .logo__icon {
    block-size: var(--space-16);
    inline-size: var(--space-16);
  }

  .logo__text {
    block-size: var(--space-12);
  }

  .heading {
    font-size: clamp(4.5rem, 4rem + 2.5vw, 6rem);
  }
}

/* Extra large devices (1280px and up) */
@media (min-width: 1280px) {
  .page__content {
    max-inline-size: var(--max-width-5xl);
  }
}

/* Stack form on very small screens (below 356px) */
@media (max-width: 355px) {
  .form__inner {
    flex-direction: column;
    gap: var(--space-2);
  }

  .form__input {
    inline-size: 100%;
  }

  .button {
    inline-size: 100%;
  }
}

/* Adjust form sizing on larger screens */
@media (min-width: 768px) {
  .form__input {
    padding-block: var(--space-3);
    padding-inline: var(--space-4);
    font-size: var(--font-size-base);
  }

  .form__input::placeholder {
    font-size: var(--font-size-base);
  }

  .button {
    padding-block: var(--space-3);
    padding-inline: var(--space-6);
    font-size: var(--font-size-base);
  }
}

/* ============================================
   ACCESSIBILITY & USER PREFERENCES
   ============================================ */

/* Respect user's motion preferences */
@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;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .form {
    border-width: var(--border-width-thick);
  }

  .button:focus-visible,
  .form__input:focus-visible {
    outline-width: 3px;
  }
}

/* Dark mode adjustments (already dark, but for completeness) */
@media (prefers-color-scheme: dark) {
  /* Already optimized for dark mode */
}

/* Focus visible for all interactive elements */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}