/* ==========================================================================
   insta2pdf — frontend styles
   Mobile-first, responsive, minimal aesthetic.
   ========================================================================== */

/* --- Design tokens --- */
:root {
  /* Color palette — neutral with a single accent */
  --color-bg: #f7f7f8;
  --color-surface: #ffffff;
  --color-border: #e2e2e6;
  --color-border-focus: #b1b1bb;
  --color-text: #1a1a1f;
  --color-text-muted: #6b6b73;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-accent-active: #1e40af;
  --color-accent-light: #eff6ff;
  --color-secondary: #f3f4f6;
  --color-secondary-hover: #e5e7eb;
  --color-secondary-text: #374151;
  --color-error-bg: #fef2f2;
  --color-error-border: #fecaca;
  --color-error-text: #991b1b;
  --color-info-bg: #eff6ff;
  --color-info-border: #bfdbfe;
  --color-info-text: #1e40af;
  --color-progress-track: #e5e7eb;
  --color-progress-fill: #2563eb;
  --color-link: #2563eb;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --fs-h1: 1.75rem;
  --fs-h1-desktop: 2rem;
  --fs-body: 1rem;
  --fs-small: 0.875rem;
  --fs-label: 0.9375rem;
  --lh-tight: 1.25;
  --lh-normal: 1.5;

  /* Spacing scale (4px base) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Shadows */
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-focus: 0 0 0 3px rgba(37, 99, 235, 0.15);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 400ms ease;

  /* Layout */
  --container-max: 600px;
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: var(--space-6) var(--space-4);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --- Layout --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

/* --- Header --- */
header {
  text-align: center;
  padding: var(--space-4) 0 var(--space-2);
}

header h1 {
  font-size: var(--fs-h1);
  font-weight: 700;
  line-height: var(--lh-tight);
  letter-spacing: -0.02em;
  color: var(--color-text);
}

header p {
  margin-top: var(--space-2);
  font-size: var(--fs-small);
  color: var(--color-text-muted);
}

/* --- Card --- */
.card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  transition: opacity var(--transition-normal), transform var(--transition-normal);
}

/* --- Hidden --- */
.hidden {
  display: none !important;
}

/* --- Form --- */
label {
  font-size: var(--fs-label);
  font-weight: 600;
  color: var(--color-text);
}

input[type="url"] {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--fs-body);
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  -webkit-appearance: none;
  appearance: none;
}

input[type="url"]::placeholder {
  color: var(--color-text-muted);
  opacity: 1;
}

input[type="url"]:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: var(--shadow-focus);
}

/* --- Buttons --- */
.button-group {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
}

button {
  flex: 1 1 auto;
  padding: var(--space-3) var(--space-5);
  font-size: var(--fs-body);
  font-weight: 600;
  font-family: var(--font-sans);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), opacity var(--transition-fast);
  -webkit-appearance: none;
  appearance: none;
  min-height: 44px; /* touch target */
}

button:active {
  transform: translateY(1px);
}

#convert-btn {
  background-color: var(--color-accent);
  color: #fff;
}

#convert-btn:hover {
  background-color: var(--color-accent-hover);
}

#convert-btn:active {
  background-color: var(--color-accent-active);
}

#convert-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

#reset-btn,
button.secondary {
  background-color: var(--color-secondary);
  color: var(--color-secondary-text);
  border-color: var(--color-border);
}

#reset-btn:hover,
button.secondary:hover {
  background-color: var(--color-secondary-hover);
}

/* --- Progress bar --- */
.progress-bar {
  width: 100%;
  height: 8px;
  background-color: var(--color-progress-track);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background-color: var(--color-progress-fill);
  border-radius: var(--radius-sm);
  transition: width var(--transition-slow) ease-out;
}

#progress-text {
  font-size: var(--fs-h1);
  font-weight: 700;
  text-align: center;
  line-height: var(--lh-tight);
  letter-spacing: -0.01em;
}

#progress-status {
  font-size: var(--fs-small);
  color: var(--color-text-muted);
  text-align: center;
}

/* --- Download --- */
#download-section {
  text-align: center;
  align-items: center;
}

#download-link {
  display: inline-block;
  padding: var(--space-3) var(--space-6);
  font-size: var(--fs-body);
  font-weight: 600;
  color: #fff;
  background-color: var(--color-accent);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: background-color var(--transition-fast);
  min-height: 44px;
  line-height: 1.5;
}

#download-link:hover {
  background-color: var(--color-accent-hover);
}

#download-link:active {
  background-color: var(--color-accent-active);
}

#countdown-timer {
  font-size: var(--fs-small);
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
}

/* --- Error / alert --- */
.alert {
  border-color: var(--color-error-border);
  background-color: var(--color-error-bg);
}

.alert p {
  color: var(--color-error-text);
  font-size: var(--fs-body);
  line-height: var(--lh-normal);
}

/* --- Notice banner --- */
.notice-banner {
  border: 1px solid var(--color-info-border);
  background-color: var(--color-info-bg);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
}

.notice-banner p {
  color: var(--color-info-text);
  font-size: var(--fs-small);
  line-height: var(--lh-normal);
  margin: 0;
}

/* --- Responsive: tablet+ --- */
@media (min-width: 640px) {
  body {
    padding: var(--space-10) var(--space-6);
  }

  header h1 {
    font-size: var(--fs-h1-desktop);
  }

  .button-group {
    flex-wrap: nowrap;
  }
}

/* --- Reduced motion --- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}