/* ============================================================
   GradSpark — Atoms (Stage 2)
   Each atom = one base class + modifier classes.
   Naming: .gs-<atom>[--<variant>] for variants,
           [data-state] / :hover / :focus-visible / :disabled for states.
   ============================================================ */

/* ============================================================
   Icon
   ============================================================ */
.gs-icon {
  width: 20px;
  height: 20px;
  flex: 0 0 auto;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.gs-icon--16 { width: 16px; height: 16px; stroke-width: 1.25; }
.gs-icon--20 { width: 20px; height: 20px; stroke-width: 1.5; }
.gs-icon--24 { width: 24px; height: 24px; stroke-width: 1.5; }

/* ============================================================
   Button
   ------------------------------------------------------------
   Variants: --primary --secondary --outline --ghost --danger --link
   Sizes:    --sm --md (default) --lg --xl
   States:   :hover :active :focus-visible :disabled  +  [data-loading]
   Modifiers: --full (fill container), --icon (square icon button)
   ============================================================ */
.gs-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: var(--fw-semibold);
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  user-select: none;
  text-decoration: none;
  white-space: nowrap;
  transition:
    background-color var(--duration-2) var(--ease-out),
    color var(--duration-2) var(--ease-out),
    border-color var(--duration-2) var(--ease-out),
    box-shadow var(--duration-2) var(--ease-out),
    transform var(--duration-1) var(--ease-out);
  /* default = md */
  height: 40px;
  padding: 0 var(--space-4);
  font-size: 16px;
  line-height: 24px;
}
.gs-btn:hover:not(:disabled):not([data-loading="true"]) { transform: translateY(-1px); }
.gs-btn:active:not(:disabled) { transform: translateY(0); }
.gs-btn:focus-visible { outline: none; box-shadow: var(--shadow-focus); }
.gs-btn:disabled,
.gs-btn[aria-disabled="true"] {
  cursor: not-allowed;
  background: var(--action-primary-disabled-bg) !important;
  color: var(--action-primary-disabled-fg) !important;
  border-color: transparent !important;
  transform: none !important;
}
.gs-btn .gs-icon { width: 20px; height: 20px; }

/* sizes */
.gs-btn--sm { height: 32px; padding: 0 var(--space-3); font-size: 14px; line-height: 20px; }
.gs-btn--sm .gs-icon { width: 16px; height: 16px; }
.gs-btn--md { height: 40px; padding: 0 var(--space-4); font-size: 16px; line-height: 24px; }
.gs-btn--lg { height: 48px; padding: 0 var(--space-5); font-size: 16px; line-height: 24px; }
.gs-btn--xl { height: 56px; padding: 0 var(--space-6); font-size: 18px; line-height: 28px; }
.gs-btn--xl .gs-icon { width: 24px; height: 24px; }

/* type — primary */
.gs-btn--primary {
  background: var(--action-primary-default);
  color: var(--action-primary-fg);
}
.gs-btn--primary:hover:not(:disabled) { background: var(--action-primary-hover); }
.gs-btn--primary:active:not(:disabled) { background: var(--action-primary-active); }

/* type — secondary */
.gs-btn--secondary {
  background: var(--action-secondary-default);
  color: var(--action-secondary-fg);
}
.gs-btn--secondary:hover:not(:disabled) { background: var(--action-secondary-hover); }
.gs-btn--secondary:active:not(:disabled) { background: var(--action-secondary-active); }

/* type — outline */
.gs-btn--outline {
  background: transparent;
  color: var(--text-primary);
  border-color: var(--action-outline-border);
}
.gs-btn--outline:hover:not(:disabled) { background: var(--action-outline-hover-bg); border-color: var(--border-strong); }
.gs-btn--outline:active:not(:disabled) { background: var(--bg-muted); }
.gs-btn--outline:disabled { border-color: var(--border-default) !important; }

/* type — ghost */
.gs-btn--ghost {
  background: transparent;
  color: var(--text-primary);
}
.gs-btn--ghost:hover:not(:disabled) { background: var(--action-ghost-hover-bg); }
.gs-btn--ghost:active:not(:disabled) { background: var(--bg-muted); }

/* type — danger */
.gs-btn--danger {
  background: var(--action-danger-default);
  color: var(--action-danger-fg);
}
.gs-btn--danger:hover:not(:disabled) { background: var(--action-danger-hover); }
.gs-btn--danger:active:not(:disabled) { background: var(--action-danger-active); }

/* type — link */
.gs-btn--link {
  background: transparent;
  color: var(--text-link);
  height: auto;
  padding: 0;
  border-radius: 0;
}
.gs-btn--link:hover:not(:disabled) { text-decoration: underline; transform: none; }
.gs-btn--link:disabled { background: transparent !important; }

/* full width */
.gs-btn--full { width: 100%; }

/* loading */
.gs-btn[data-loading="true"] { cursor: progress; pointer-events: none; }
.gs-btn[data-loading="true"] .gs-btn__label { opacity: 0.7; }

/* IconButton (square) */
.gs-icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
  transition: background-color var(--duration-2) var(--ease-out), box-shadow var(--duration-2) var(--ease-out);
}
.gs-icon-btn:hover:not(:disabled) { background: var(--action-ghost-hover-bg); }
.gs-icon-btn:focus-visible { outline: none; box-shadow: var(--shadow-focus); }
.gs-icon-btn:disabled { color: var(--text-disabled); cursor: not-allowed; }
.gs-icon-btn--sm { width: 32px; height: 32px; }
.gs-icon-btn--lg { width: 48px; height: 48px; }
.gs-icon-btn--outline { border-color: var(--action-outline-border); }
.gs-icon-btn--primary { background: var(--action-primary-default); color: var(--action-primary-fg); }
.gs-icon-btn--primary:hover:not(:disabled) { background: var(--action-primary-hover); }
.gs-icon-btn--danger { color: var(--action-danger-default); }
.gs-icon-btn--danger:hover:not(:disabled) { background: var(--status-danger-bg); color: var(--action-danger-hover); }

/* ============================================================
   Spinner
   ============================================================ */
.gs-spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid var(--border-default);
  border-top-color: var(--action-primary-default);
  animation: gs-spin 800ms linear infinite;
}
.gs-spinner--16 { width: 16px; height: 16px; border-width: 2px; }
.gs-spinner--24 { width: 24px; height: 24px; border-width: 2px; }
.gs-spinner--32 { width: 32px; height: 32px; border-width: 3px; }
.gs-spinner--on-primary { border-color: rgba(255,255,255,0.35); border-top-color: #fff; }
@keyframes gs-spin { to { transform: rotate(360deg); } }

/* ============================================================
   Form — FormField, Input, Textarea, Select
   ============================================================ */
.gs-field {
  display: flex;
  flex-direction: column;
  gap: var(--space-1_5, 6px);
  width: 100%;
}
.gs-field__label {
  font-size: 14px;
  line-height: 20px;
  font-weight: var(--fw-medium);
  color: var(--text-primary);
}
.gs-field__label .gs-required { color: var(--action-danger-default); margin-left: 2px; }
.gs-field__label .gs-optional { color: var(--text-tertiary); font-weight: var(--fw-regular); margin-left: 6px; }
.gs-field__hint {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  font-size: 12px;
  line-height: 16px;
  color: var(--text-tertiary);
}
.gs-field__hint--error { color: var(--action-danger-default); }
.gs-field__hint--success { color: var(--status-success-fg); }

/* Input wrapper holds prefix/suffix icons */
.gs-input {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  height: 40px;
  padding: 0 var(--space-3);
  background: var(--bg-surface);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  transition: border-color var(--duration-2) var(--ease-out), box-shadow var(--duration-2) var(--ease-out);
}
.gs-input:hover:not([data-disabled="true"]):not([data-readonly="true"]) { border-color: var(--border-strong); }
.gs-input:focus-within {
  border-color: var(--border-focus);
  box-shadow: var(--shadow-focus);
}
.gs-input__field {
  flex: 1;
  border: 0;
  outline: none;
  background: transparent;
  padding: 0;
  font: inherit;
  color: inherit;
  min-width: 0;
}
.gs-input__field::placeholder { color: var(--text-tertiary); }
.gs-input__icon { color: var(--text-tertiary); flex: 0 0 auto; }
.gs-input__affix {
  color: var(--text-tertiary);
  font-size: 14px;
  flex: 0 0 auto;
}

/* sizes */
.gs-input--sm { height: 32px; padding: 0 var(--space-2); font-size: 14px; }
.gs-input--md { height: 40px; padding: 0 var(--space-3); font-size: 16px; }
.gs-input--lg { height: 48px; padding: 0 var(--space-4); font-size: 16px; }

/* states */
.gs-input[data-state="error"] {
  border-color: var(--border-danger);
  border-width: 1.5px;
}
.gs-input[data-state="error"]:focus-within { box-shadow: 0 0 0 4px rgba(239,68,68,0.18); }
.gs-input[data-state="success"] { border-color: var(--status-success-border); }
.gs-input[data-disabled="true"] {
  background: var(--bg-muted);
  color: var(--text-disabled);
  cursor: not-allowed;
}
.gs-input[data-disabled="true"] .gs-input__field { color: var(--text-disabled); cursor: not-allowed; }
.gs-input[data-readonly="true"] { background: var(--bg-muted); }

/* Textarea */
.gs-textarea {
  display: block;
  width: 100%;
  min-height: 96px;
  padding: var(--space-3);
  background: var(--bg-surface);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font: inherit;
  resize: vertical;
  transition: border-color var(--duration-2) var(--ease-out), box-shadow var(--duration-2) var(--ease-out);
}
.gs-textarea::placeholder { color: var(--text-tertiary); }
.gs-textarea:hover { border-color: var(--border-strong); }
.gs-textarea:focus { outline: none; border-color: var(--border-focus); box-shadow: var(--shadow-focus); }
.gs-textarea:disabled { background: var(--bg-muted); color: var(--text-disabled); cursor: not-allowed; }

/* Select (uses native + custom chevron) */
.gs-select {
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='20' height='20' viewBox='0 0 24 24' fill='none' stroke='%236B7280' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'><polyline points='6 9 12 15 18 9'/></svg>");
  background-repeat: no-repeat;
  background-position: right var(--space-3) center;
  padding-right: var(--space-10);
}

/* ============================================================
   Checkbox / Radio / Switch
   ============================================================ */
.gs-check, .gs-radio, .gs-switch {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  cursor: pointer;
  user-select: none;
  font-size: 14px;
  color: var(--text-primary);
}
.gs-check input, .gs-radio input, .gs-switch input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.gs-check__box {
  width: 18px; height: 18px;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--border-strong);
  background: var(--bg-surface);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: transparent;
  transition: background-color var(--duration-2) var(--ease-out), border-color var(--duration-2) var(--ease-out), box-shadow var(--duration-2) var(--ease-out);
}
.gs-check input:checked + .gs-check__box,
.gs-check input:indeterminate + .gs-check__box {
  background: var(--action-primary-default);
  border-color: var(--action-primary-default);
  color: #fff;
}
.gs-check input:focus-visible + .gs-check__box { box-shadow: var(--shadow-focus); }
.gs-check input:disabled + .gs-check__box { background: var(--bg-muted); border-color: var(--border-default); cursor: not-allowed; }
.gs-check__box svg { width: 14px; height: 14px; stroke: currentColor; fill: none; stroke-width: 2.5; }

.gs-radio__dot {
  width: 18px; height: 18px;
  border-radius: 50%;
  border: 1.5px solid var(--border-strong);
  background: var(--bg-surface);
  position: relative;
  transition: border-color var(--duration-2) var(--ease-out), box-shadow var(--duration-2) var(--ease-out);
}
.gs-radio__dot::after {
  content: "";
  position: absolute;
  inset: 0;
  margin: auto;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--action-primary-default);
  transform: scale(0);
  transition: transform var(--duration-2) var(--ease-out);
}
.gs-radio input:checked + .gs-radio__dot { border-color: var(--action-primary-default); border-width: 2px; }
.gs-radio input:checked + .gs-radio__dot::after { transform: scale(1); }
.gs-radio input:focus-visible + .gs-radio__dot { box-shadow: var(--shadow-focus); }
.gs-radio input:disabled + .gs-radio__dot { background: var(--bg-muted); border-color: var(--border-default); cursor: not-allowed; }

.gs-switch__track {
  width: 36px; height: 20px;
  border-radius: var(--radius-pill);
  background: var(--border-strong);
  position: relative;
  transition: background-color var(--duration-3) var(--ease-out), box-shadow var(--duration-2) var(--ease-out);
}
.gs-switch__track::after {
  content: "";
  position: absolute;
  top: 2px; left: 2px;
  width: 16px; height: 16px;
  background: #fff;
  border-radius: 50%;
  box-shadow: var(--shadow-1);
  transition: transform var(--duration-3) var(--ease-out);
}
.gs-switch input:checked + .gs-switch__track { background: var(--action-primary-default); }
.gs-switch input:checked + .gs-switch__track::after { transform: translateX(16px); }
.gs-switch input:focus-visible + .gs-switch__track { box-shadow: var(--shadow-focus); }
.gs-switch input:disabled + .gs-switch__track { opacity: 0.6; cursor: not-allowed; }

/* ============================================================
   Badge
   ============================================================ */
.gs-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  height: 24px;
  padding: 0 var(--space-2_5, 10px);
  border-radius: var(--radius-pill);
  font-size: 12px;
  line-height: 1;
  font-weight: var(--fw-semibold);
  letter-spacing: 0.2px;
  border: 1px solid transparent;
  white-space: nowrap;
}
.gs-badge--sm { height: 20px; padding: 0 var(--space-2); font-size: 11px; }
.gs-badge .gs-icon { width: 12px; height: 12px; stroke-width: 2; }
.gs-badge__dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: currentColor;
}

/* subtle (default style) */
.gs-badge--neutral { background: var(--color-neutral-100); color: var(--color-neutral-700); }
.gs-badge--info    { background: var(--status-info-bg); color: var(--status-info-fg); }
.gs-badge--success { background: var(--status-success-bg); color: var(--status-success-fg); }
.gs-badge--warning { background: var(--status-warning-bg); color: var(--status-warning-fg); }
.gs-badge--danger  { background: var(--status-danger-bg); color: var(--status-danger-fg); }
.gs-badge--primary { background: var(--color-blue-100); color: var(--color-blue-700); }

/* solid */
.gs-badge--solid.gs-badge--neutral { background: var(--color-neutral-700); color: #fff; }
.gs-badge--solid.gs-badge--info    { background: var(--color-blue-500); color: #fff; }
.gs-badge--solid.gs-badge--success { background: var(--color-green-500); color: #fff; }
.gs-badge--solid.gs-badge--warning { background: var(--color-amber-500); color: #fff; }
.gs-badge--solid.gs-badge--danger  { background: var(--color-red-500); color: #fff; }
.gs-badge--solid.gs-badge--primary { background: var(--color-blue-500); color: #fff; }

/* outline */
.gs-badge--outline { background: transparent; }
.gs-badge--outline.gs-badge--neutral { border-color: var(--color-neutral-300); color: var(--color-neutral-700); }
.gs-badge--outline.gs-badge--info    { border-color: var(--status-info-border); color: var(--status-info-fg); }
.gs-badge--outline.gs-badge--success { border-color: var(--status-success-border); color: var(--status-success-fg); }
.gs-badge--outline.gs-badge--warning { border-color: var(--status-warning-border); color: var(--status-warning-fg); }
.gs-badge--outline.gs-badge--danger  { border-color: var(--status-danger-border); color: var(--status-danger-fg); }

/* ============================================================
   Tag (interactive, removable)
   ============================================================ */
.gs-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  height: 28px;
  padding: 0 var(--space-3);
  border-radius: var(--radius-pill);
  background: var(--bg-muted);
  color: var(--text-primary);
  border: 1px solid var(--border-default);
  font-size: 13px;
  font-weight: var(--fw-medium);
  cursor: pointer;
  transition: background-color var(--duration-2) var(--ease-out), border-color var(--duration-2) var(--ease-out);
}
.gs-tag:hover { background: var(--color-neutral-200); }
.gs-tag[aria-pressed="true"], .gs-tag--selected {
  background: var(--color-blue-100);
  color: var(--color-blue-700);
  border-color: var(--color-blue-300);
}
.gs-tag__remove {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px; height: 16px;
  border-radius: 50%;
  margin-right: -4px;
  margin-left: 2px;
  color: inherit;
  opacity: 0.6;
}
.gs-tag__remove:hover { opacity: 1; background: rgba(0,0,0,0.06); }

/* ============================================================
   Avatar
   ============================================================ */
.gs-avatar {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px; height: 32px;
  border-radius: 50%;
  background: var(--color-neutral-200);
  color: var(--text-primary);
  font-weight: var(--fw-semibold);
  font-size: 13px;
  overflow: hidden;
  flex: 0 0 auto;
}
.gs-avatar img { width: 100%; height: 100%; object-fit: cover; }
.gs-avatar--xs  { width: 20px; height: 20px; font-size: 10px; }
.gs-avatar--sm  { width: 24px; height: 24px; font-size: 11px; }
.gs-avatar--md  { width: 32px; height: 32px; font-size: 13px; }
.gs-avatar--lg  { width: 40px; height: 40px; font-size: 14px; }
.gs-avatar--xl  { width: 56px; height: 56px; font-size: 18px; }
.gs-avatar--2xl { width: 80px; height: 80px; font-size: 24px; }

.gs-avatar__status {
  position: absolute;
  right: 0; bottom: 0;
  width: 25%; height: 25%;
  min-width: 8px; min-height: 8px;
  border-radius: 50%;
  border: 2px solid var(--bg-surface);
  background: var(--color-neutral-400);
}
.gs-avatar__status--online { background: var(--color-green-500); }
.gs-avatar__status--busy   { background: var(--color-red-500); }
.gs-avatar__status--away   { background: var(--color-amber-500); }

.gs-avatar-group {
  display: inline-flex;
  align-items: center;
}
.gs-avatar-group .gs-avatar {
  border: 2px solid var(--bg-surface);
  margin-left: -8px;
}
.gs-avatar-group .gs-avatar:first-child { margin-left: 0; }
.gs-avatar-group--more {
  background: var(--color-neutral-100);
  color: var(--text-secondary);
}

/* ============================================================
   Divider, Kbd
   ============================================================ */
.gs-divider {
  border: 0;
  border-top: 1px solid var(--border-default);
  margin: 0;
}
.gs-divider--vertical {
  border-top: 0;
  border-left: 1px solid var(--border-default);
  align-self: stretch;
  width: 0;
}
.gs-divider--dashed { border-top-style: dashed; }

.gs-kbd {
  display: inline-flex;
  align-items: center;
  padding: 2px 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-secondary);
  background: var(--bg-muted);
  border: 1px solid var(--border-default);
  border-bottom-width: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================================
   Progress — Bar + Circle
   ============================================================ */
.gs-progress {
  width: 100%;
  height: 8px;
  background: var(--color-neutral-200);
  border-radius: var(--radius-pill);
  overflow: hidden;
}
.gs-progress--sm { height: 4px; }
.gs-progress--lg { height: 12px; }
.gs-progress__fill {
  height: 100%;
  background: var(--action-primary-default);
  border-radius: var(--radius-pill);
  transition: width var(--duration-4) var(--ease-out);
}
.gs-progress--success .gs-progress__fill { background: var(--color-green-500); }
.gs-progress--warning .gs-progress__fill { background: var(--color-amber-500); }
.gs-progress--danger  .gs-progress__fill { background: var(--color-red-500); }

.gs-progress-circle {
  --size: 96px;
  --thickness: 10px;
  --value: 0;
  --track: var(--color-neutral-200);
  --fill: var(--action-primary-default);
  width: var(--size);
  height: var(--size);
  border-radius: 50%;
  background:
    conic-gradient(var(--fill) calc(var(--value) * 1%), var(--track) 0);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
.gs-progress-circle::after {
  content: "";
  position: absolute;
  inset: var(--thickness);
  border-radius: 50%;
  background: var(--bg-surface);
}
.gs-progress-circle__label {
  position: relative;
  z-index: 1;
  font-weight: var(--fw-bold);
  font-size: calc(var(--size) / 5);
  color: var(--text-primary);
}

/* ============================================================
   Specimen helpers
   ============================================================ */
.swatch {
  display: flex;
  flex-direction: column;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-default);
  background: var(--bg-surface);
}
.swatch__chip { height: 72px; }
.swatch__meta {
  padding: var(--space-3);
  display: flex; flex-direction: column; gap: 2px;
}
.swatch__name { font-size: 13px; font-weight: var(--fw-semibold); color: var(--text-primary); }
.swatch__hex { font-family: var(--font-mono); font-size: 11px; color: var(--text-tertiary); }

.matrix {
  display: grid;
  gap: var(--space-3);
  padding: var(--space-6);
  background: var(--bg-surface);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
}

.row-label {
  font-size: 12px;
  font-weight: var(--fw-semibold);
  letter-spacing: 0.6px;
  text-transform: uppercase;
  color: var(--text-tertiary);
  padding-right: var(--space-3);
}

.elev-card {
  background: var(--bg-surface);
  height: 120px;
  border-radius: var(--radius-lg);
  display: flex; align-items: center; justify-content: center;
  font-weight: var(--fw-semibold);
  color: var(--text-secondary);
}

.spacing-bar {
  height: 16px;
  background: var(--color-blue-300);
  border-radius: 2px;
}