/* Spec: design.md — UsefulTool */

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  width: 100%;
  max-width: 100%;
  min-height: 100vh;
  min-height: 100dvh;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--text-primary);
  background: var(--bg-deep);
  overflow-x: clip;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.container {
  width: 100%;
  max-width: var(--content-max);
  margin-inline: auto;
  min-width: 0;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-2);
  z-index: 1000;
  padding: var(--space-1) var(--space-2);
  background: var(--accent);
  color: var(--text-on-accent);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.skip-link:focus {
  top: max(var(--space-2), env(safe-area-inset-top));
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.bg-mesh {
  position: fixed;
  inset: 0;
  z-index: -2;
  background: var(--bg-deep);
  pointer-events: none;
}

.layout {
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 100%;
  min-height: 100vh;
  min-height: 100dvh;
  overflow-x: clip;
}

/* App shell */
.app-shell {
  display: flex;
  flex: 1;
  width: 100%;
  min-width: 0;
  min-height: 0;
}

.app-content {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-width: 0;
  min-height: 0;
}

.app-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  height: var(--header-height);
  padding-inline: max(var(--space-2), env(safe-area-inset-left))
    max(var(--space-2), env(safe-area-inset-right));
  padding-top: env(safe-area-inset-top, 0px);
  border-bottom: 1px solid var(--glass-border);
  background: color-mix(in srgb, var(--bg-deep) 92%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.app-header__title {
  margin: 0;
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--text-primary);
}

.app-sidebar__toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  background: var(--glass-bg);
  cursor: pointer;
  transition: border-color var(--transition-fast);
}

.app-sidebar__toggle:hover {
  border-color: color-mix(in srgb, var(--accent) 35%, var(--glass-border));
}

.app-sidebar__toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.app-sidebar__toggle-bars {
  display: flex;
  flex-direction: column;
  gap: 5px;
  width: 1.125rem;
}

.app-sidebar__toggle-bars span {
  display: block;
  height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.app-sidebar__backdrop {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 90;
  background: rgba(30, 41, 59, 0.35);
}

.app-sidebar__backdrop.is-visible {
  display: block;
}

/* Sidebar */
.app-sidebar {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
  display: flex;
  flex-direction: column;
  width: var(--sidebar-width);
  height: 100dvh;
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
  border-right: 1px solid var(--glass-border);
  background: var(--bg-deep);
  transform: translateX(-100%);
  transition: transform var(--transition-base);
}

.app-sidebar.is-open {
  transform: translateX(0);
}

.app-sidebar__brand {
  padding: var(--space-3) var(--space-2);
  border-bottom: 1px solid var(--glass-border);
}

.app-sidebar__logo {
  font-size: var(--text-lg);
  font-weight: 600;
  color: #000000;
  text-decoration: none;
}

.app-sidebar__logo:hover {
  text-decoration: none;
  color: var(--accent);
}

.app-sidebar__nav {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-2);
}

.app-sidebar__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.app-sidebar__link {
  display: block;
  padding: 0.65rem var(--space-2);
  min-height: 44px;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  border-left: 3px solid transparent;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), border-color var(--transition-fast),
    background var(--transition-fast);
}

.app-sidebar__link:hover {
  color: var(--text-primary);
  text-decoration: none;
  background: var(--surface-muted);
}

.app-sidebar__link.is-active {
  color: var(--text-primary);
  border-left-color: var(--accent);
  background: var(--surface-muted);
}

.app-sidebar__link:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Tool panel */
.tool-panel {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-3) max(var(--space-2), env(safe-area-inset-right))
    max(var(--space-3), env(safe-area-inset-bottom))
    max(var(--space-2), env(safe-area-inset-left));
}

.tool-panel__title {
  margin: 0 0 var(--space-1);
  font-size: var(--text-2xl);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.tool-panel__desc {
  margin: 0 0 var(--space-3);
  color: var(--text-muted);
  font-size: var(--text-sm);
  line-height: 1.6;
}

/* Glass card */
.glass-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-3);
  box-shadow: var(--shadow-card);
}

.glass-card--static:hover {
  transform: none;
  box-shadow: var(--shadow-card);
}

/* Tool grid (home) */
.tool-grid {
  display: grid;
  gap: var(--space-2);
  grid-template-columns: 1fr;
  min-width: 0;
}

.tool-card {
  display: flex;
  flex-direction: column;
  padding: var(--space-3);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-top: 3px solid var(--accent);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  text-decoration: none;
  color: inherit;
  cursor: pointer;
  transition: transform var(--transition-smooth), box-shadow var(--transition-smooth),
    border-color var(--transition-base);
}

.tool-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card), var(--shadow-glow-cyan);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--glass-border));
  text-decoration: none;
}

.tool-card:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.tool-card__label {
  display: inline-block;
  margin-bottom: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.tool-card__title {
  margin: 0;
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--text-primary);
}

.tool-card:hover .tool-card__title {
  color: var(--accent);
}

.tool-card__desc {
  margin: var(--space-1) 0 0;
  font-size: var(--text-sm);
  color: var(--text-muted);
  line-height: 1.55;
}

/* Tool form */
.tool-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.tool-form__row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: stretch;
}

.tool-form__label {
  display: block;
  margin-bottom: var(--space-1);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--text-primary);
}

.tool-form__input {
  flex: 1;
  min-width: 0;
  width: 100%;
  padding: 0.65rem var(--space-2);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--text-primary);
  background: var(--bg-deep);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast);
}

.tool-form__input:focus {
  outline: none;
  border-color: var(--accent);
}

.tool-form__input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.tool-form__file {
  width: 100%;
  font-size: var(--text-sm);
  color: var(--text-muted);
}

.tool-form__textarea {
  width: 100%;
  min-height: 12rem;
  padding: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--text-primary);
  background: var(--bg-deep);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  resize: vertical;
}

.tool-form__textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.tool-form__btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  min-width: 44px;
  padding: 0.65rem var(--space-3);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--text-on-accent);
  background: var(--accent);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.tool-form__btn:hover:not(:disabled) {
  opacity: 0.9;
}

.tool-form__btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.tool-form__btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.tool-form__btn--secondary {
  color: var(--text-primary);
  background: var(--surface-muted);
  border: 1px solid var(--glass-border);
}

.tool-form__status {
  margin: 0;
  font-size: var(--text-sm);
  color: var(--text-muted);
}

.tool-form__error {
  margin: 0;
  font-size: var(--text-sm);
  color: var(--text-error);
  overflow-wrap: anywhere;
}

.tool-form__disclaimer {
  margin: var(--space-2) 0 0;
  font-size: var(--text-xs);
  color: var(--text-muted);
  line-height: 1.5;
}

.tool-form__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

/* Site footer */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--glass-border);
  padding-block: var(--space-2);
  padding-inline: max(var(--space-2), env(safe-area-inset-left))
    max(var(--space-2), env(safe-area-inset-right));
  padding-bottom: max(var(--space-2), env(safe-area-inset-bottom));
  background: var(--bg-deep);
}

.site-footer__inner {
  min-width: 0;
  text-align: center;
}

.site-footer__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.2rem 0.35rem;
  margin: 0;
  font-size: var(--text-xs);
  line-height: 1.4;
  overflow-wrap: anywhere;
}

.site-footer__sep {
  color: var(--text-muted);
  user-select: none;
}

.site-footer__contact {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.25rem;
  color: var(--text-muted);
}

.site-footer__contact-label {
  user-select: none;
}

.site-footer a {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-decoration: none;
  overflow-wrap: anywhere;
  transition: color var(--transition-base);
}

.site-footer a:hover {
  color: var(--accent);
  text-decoration: none;
}

.site-footer a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Desktop */
@media (min-width: 768px) {
  .app-header {
    display: none;
  }

  .app-sidebar__toggle {
    display: none;
  }

  .app-sidebar__backdrop {
    display: none !important;
  }

  .app-sidebar {
    position: sticky;
    top: 0;
    flex-shrink: 0;
    transform: none;
    height: auto;
    align-self: stretch;
  }

  .tool-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .tool-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

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

  .tool-card:hover {
    transform: none;
  }
}