/**
 * OS TigerLab Design System v2 — COMPONENTS
 * Librería core. Todos los componentes usan prefijo .ostl-* para evitar
 * choques con CSS legacy. Compatibilidad de clases viejas en compat.css.
 *
 * Componentes incluidos:
 *   Button, Card, Input/Form, Modal, Toast, Alert, Badge, Skeleton,
 *   Avatar, Progress, Tabs, Accordion, Pagination, Empty, Tooltip,
 *   Dropdown, Switch, Spinner.
 */

/* ================================================================== */
/*  BUTTON · .ostl-btn                                                 */
/* ================================================================== */
.ostl-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--sp-2);
    height: var(--btn-h-md);
    padding-inline: var(--btn-px-md);
    font-family: var(--font-body);
    font-size: var(--btn-fs-md);
    font-weight: var(--fw-semi);
    line-height: 1;
    letter-spacing: 0;
    border: 1px solid transparent;
    border-radius: var(--btn-radius);
    background: transparent;
    color: var(--color-text-primary);
    cursor: pointer;
    user-select: none;
    text-decoration: none;
    white-space: nowrap;
    transition: background-color var(--d-fast) var(--ease-smooth),
                border-color var(--d-fast) var(--ease-smooth),
                color var(--d-fast) var(--ease-smooth),
                transform var(--d-fast) var(--ease-spring),
                box-shadow var(--d-fast) var(--ease-smooth);
    -webkit-tap-highlight-color: transparent;
}
.ostl-btn:focus-visible {
    box-shadow: var(--focus-ring-shadow);
}
.ostl-btn:active:not(:disabled):not([aria-disabled="true"]) {
    transform: scale(0.97);
    transition-duration: var(--d-instant);
}
.ostl-btn:disabled,
.ostl-btn[aria-disabled="true"] {
    opacity: 0.45;
    cursor: not-allowed;
    pointer-events: none;
}

/* Sizes */
.ostl-btn--sm { height: var(--btn-h-sm); padding-inline: var(--btn-px-sm); font-size: var(--btn-fs-sm); }
.ostl-btn--lg { height: var(--btn-h-lg); padding-inline: var(--btn-px-lg); font-size: var(--btn-fs-lg); }

/* Variants */
.ostl-btn--primary {
    background: var(--color-accent);
    color: var(--color-text-on-accent);
    border-color: var(--color-accent);
}
.ostl-btn--primary:hover:not(:disabled) {
    background: var(--color-accent-hover);
    border-color: var(--color-accent-hover);
    box-shadow: 0 4px 16px var(--color-accent-soft);
}

.ostl-btn--secondary {
    background: transparent;
    color: var(--color-text-primary);
    border-color: var(--color-border-strong);
}
.ostl-btn--secondary:hover:not(:disabled) {
    background: var(--color-bg-elevated);
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.ostl-btn--ghost {
    background: transparent;
    color: var(--color-text-secondary);
    border-color: transparent;
}
.ostl-btn--ghost:hover:not(:disabled) {
    background: var(--color-bg-elevated);
    color: var(--color-text-primary);
}

.ostl-btn--danger {
    background: var(--color-danger);
    color: #fff;
    border-color: var(--color-danger);
}
.ostl-btn--danger:hover:not(:disabled) {
    background: var(--color-danger-hover);
    border-color: var(--color-danger-hover);
}

.ostl-btn--link {
    height: auto;
    padding: 0;
    background: transparent;
    color: var(--color-accent);
    border: none;
    text-decoration: underline;
    text-underline-offset: 3px;
}
.ostl-btn--link:hover:not(:disabled) {
    color: var(--color-accent-hover);
}

/* Icon-only */
.ostl-btn--icon {
    width: var(--btn-h-md);
    padding: 0;
}
.ostl-btn--icon.ostl-btn--sm { width: var(--btn-h-sm); }
.ostl-btn--icon.ostl-btn--lg { width: var(--btn-h-lg); }

/* Block (full-width) */
.ostl-btn--block { width: 100%; }

/* Loading state */
.ostl-btn[data-loading="true"] {
    color: transparent !important;
    pointer-events: none;
    position: relative;
}
.ostl-btn[data-loading="true"]::after {
    content: '';
    position: absolute;
    inset: 0;
    margin: auto;
    width: 18px;
    height: 18px;
    border: 2px solid currentColor;
    border-top-color: transparent;
    border-radius: 50%;
    color: var(--color-text-on-accent);
    animation: ostl-spin 700ms linear infinite;
}
.ostl-btn--secondary[data-loading="true"]::after,
.ostl-btn--ghost[data-loading="true"]::after {
    color: var(--color-text-primary);
}

/* Shimmer accent en hover (subtle) */
.ostl-btn--primary {
    position: relative;
    overflow: hidden;
}
.ostl-btn--primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 60%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,.18), transparent);
    transition: left var(--d-slower) var(--ease-out-cubic);
    pointer-events: none;
}
.ostl-btn--primary:hover::before { left: 120%; }

/* ================================================================== */
/*  CARD · .ostl-card                                                  */
/* ================================================================== */
.ostl-card {
    display: flex;
    flex-direction: column;
    background: var(--card-bg);
    border: var(--card-border);
    border-radius: var(--card-radius);
    padding: var(--card-padding);
    box-shadow: var(--card-shadow), var(--card-inset);
    transition: transform var(--d-base) var(--ease-spring),
                box-shadow var(--d-base) var(--ease-out-cubic),
                border-color var(--d-fast) var(--ease-smooth);
    contain: layout paint;
}
.ostl-card:focus-within {
    border-color: color-mix(in oklab, var(--color-accent-2) 38%, var(--color-border-default));
    box-shadow: var(--card-shadow), var(--card-inset), 0 0 0 1px var(--color-accent-2-soft);
}
.ostl-card--interactive { cursor: pointer; }
@media (hover: hover) {
    .ostl-card--interactive:hover {
        transform: translate3d(0, -6px, 0);
        box-shadow:
            var(--shadow-4),
            var(--card-inset),
            0 0 48px color-mix(in oklab, var(--color-accent-2) 14%, transparent);
        border-color: var(--color-border-accent);
    }
}
.ostl-card--interactive:active {
    transform: translate3d(0, -1px, 0);
    transition-duration: var(--d-instant);
}

.ostl-card--flat   { box-shadow: none; }
.ostl-card--accent { border-color: var(--color-border-accent); }

.ostl-card__header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--sp-3);
    margin-bottom: var(--sp-4);
}
.ostl-card__title {
    font-family: var(--font-display);
    font-size: var(--fs-xl);
    font-weight: var(--fw-bold);
    line-height: var(--lh-xl);
    color: var(--color-text-primary);
    margin: 0;
}
.ostl-card__subtitle {
    font-size: var(--fs-sm);
    color: var(--color-text-muted);
    margin-top: var(--sp-1);
}
.ostl-card__media {
    margin: calc(var(--card-padding) * -1) calc(var(--card-padding) * -1) var(--sp-4);
    border-radius: var(--card-radius) var(--card-radius) 0 0;
    overflow: hidden;
    aspect-ratio: 16 / 9;
}
.ostl-card__media img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform var(--d-slow) var(--ease-out-cubic);
}
.ostl-card--interactive:hover .ostl-card__media img {
    transform: scale(1.04);
}
.ostl-card__body {
    flex: 1;
    color: var(--color-text-secondary);
    font-size: var(--fs-sm);
    line-height: var(--lh-base);
}
.ostl-card__footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--sp-3);
    margin-top: var(--sp-4);
    padding-top: var(--sp-4);
    border-top: 1px solid var(--color-border-subtle);
}

/* Variantes específicas de uso (course, feature, stat) */
.ostl-card--course { padding: 0; }
.ostl-card--course .ostl-card__media { margin: 0; border-radius: var(--card-radius) var(--card-radius) 0 0; }
.ostl-card--course > *:not(.ostl-card__media) {
    padding-inline: var(--card-padding);
}
.ostl-card--course > *:not(.ostl-card__media):first-of-type { padding-top: var(--sp-4); }
.ostl-card--course > *:not(.ostl-card__media):last-child { padding-bottom: var(--card-padding); }

.ostl-card--stat {
    text-align: center;
    align-items: center;
}
.ostl-card--stat .ostl-card__title {
    font-size: var(--fs-4xl);
    color: var(--color-accent);
}

/* ================================================================== */
/*  FORM · .ostl-input / .ostl-textarea / .ostl-select                 */
/* ================================================================== */
.ostl-field {
    display: flex;
    flex-direction: column;
    gap: var(--sp-1);
}
.ostl-label {
    font-size: var(--fs-sm);
    font-weight: var(--fw-medium);
    color: var(--color-text-secondary);
    line-height: var(--lh-sm);
}
.ostl-label--required::after {
    content: ' *';
    color: var(--color-danger);
}

.ostl-input,
.ostl-textarea,
.ostl-select {
    width: 100%;
    height: var(--input-h);
    padding: 0 var(--input-px);
    font-family: inherit;
    font-size: var(--fs-base);
    line-height: 1.5;
    color: var(--color-text-primary);
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: var(--input-radius);
    transition: border-color var(--d-fast) var(--ease-smooth),
                box-shadow var(--d-fast) var(--ease-smooth),
                background-color var(--d-fast) var(--ease-smooth);
    appearance: none;
    -webkit-appearance: none;
}
.ostl-textarea {
    height: auto;
    min-height: 96px;
    padding: var(--sp-3) var(--input-px);
    resize: vertical;
}
.ostl-input::placeholder,
.ostl-textarea::placeholder {
    color: var(--color-text-muted);
}
.ostl-input:hover,
.ostl-textarea:hover,
.ostl-select:hover {
    border-color: var(--color-border-strong);
}
.ostl-input:focus-visible,
.ostl-textarea:focus-visible,
.ostl-select:focus-visible {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-soft);
}
.ostl-input[aria-invalid="true"],
.ostl-textarea[aria-invalid="true"],
.ostl-select[aria-invalid="true"] {
    border-color: var(--color-danger);
}
.ostl-input:disabled,
.ostl-textarea:disabled,
.ostl-select:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    background: var(--color-bg-muted);
}

.ostl-select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='none' stroke='%23A3A3A3' stroke-width='2' stroke-linecap='round' d='M1 1l5 5 5-5'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--sp-4) center;
    padding-right: var(--sp-10);
}

.ostl-help {
    font-size: var(--fs-xs);
    color: var(--color-text-muted);
}
.ostl-error {
    font-size: var(--fs-xs);
    color: var(--color-danger);
    display: flex;
    align-items: center;
    gap: var(--sp-1);
}

/* Checkbox / Radio */
.ostl-checkbox,
.ostl-radio {
    display: inline-flex;
    align-items: center;
    gap: var(--sp-2);
    cursor: pointer;
    user-select: none;
    font-size: var(--fs-sm);
    color: var(--color-text-secondary);
}
.ostl-checkbox input,
.ostl-radio input {
    appearance: none;
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    margin: 0;
    border: 1px solid var(--color-border-strong);
    background: var(--input-bg);
    border-radius: 4px;
    cursor: pointer;
    flex-shrink: 0;
    display: grid;
    place-items: center;
    transition: var(--t-all-fast);
}
.ostl-radio input { border-radius: 50%; }
.ostl-checkbox input:checked,
.ostl-radio input:checked {
    background: var(--color-accent);
    border-color: var(--color-accent);
}
.ostl-checkbox input:checked::after {
    content: '';
    width: 10px;
    height: 6px;
    border-left: 2px solid var(--color-text-on-accent);
    border-bottom: 2px solid var(--color-text-on-accent);
    transform: rotate(-45deg) translate(1px, -1px);
}
.ostl-radio input:checked::after {
    content: '';
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--color-text-on-accent);
}
.ostl-checkbox input:focus-visible,
.ostl-radio input:focus-visible {
    box-shadow: 0 0 0 3px var(--color-accent-soft);
}

/* Switch */
.ostl-switch {
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: var(--sp-2);
    cursor: pointer;
    user-select: none;
}
.ostl-switch input { position: absolute; opacity: 0; pointer-events: none; }
.ostl-switch__track {
    width: 40px;
    height: 22px;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border-strong);
    border-radius: var(--r-pill);
    position: relative;
    transition: background-color var(--d-fast) var(--ease-smooth),
                border-color var(--d-fast) var(--ease-smooth);
    flex-shrink: 0;
}
.ostl-switch__track::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 16px;
    height: 16px;
    background: var(--color-text-secondary);
    border-radius: 50%;
    transition: transform var(--d-fast) var(--ease-spring),
                background-color var(--d-fast) var(--ease-smooth);
}
.ostl-switch input:checked + .ostl-switch__track {
    background: var(--color-accent);
    border-color: var(--color-accent);
}
.ostl-switch input:checked + .ostl-switch__track::after {
    transform: translateX(18px);
    background: var(--color-text-on-accent);
}
.ostl-switch input:focus-visible + .ostl-switch__track {
    box-shadow: 0 0 0 3px var(--color-accent-soft);
}

/* ================================================================== */
/*  MODAL · .ostl-modal                                                */
/* ================================================================== */
.ostl-modal-backdrop {
    position: fixed;
    inset: 0;
    background: var(--color-bg-overlay);
    z-index: var(--z-modal);
    display: grid;
    place-items: center;
    padding: var(--sp-4);
    animation: ostl-backdrop-in var(--d-base) var(--ease-out-cubic);
    -webkit-backdrop-filter: blur(6px);
    backdrop-filter: blur(6px);
}
.ostl-modal-backdrop[data-closing="true"] {
    animation: ostl-backdrop-in var(--d-fast) var(--ease-in-out-cubic) reverse forwards;
}

.ostl-modal {
    background: var(--modal-bg);
    border: 1px solid var(--color-border-default);
    border-radius: var(--modal-radius);
    box-shadow: var(--shadow-5);
    width: 100%;
    max-width: var(--modal-w-md);
    max-height: calc(100vh - 32px);
    display: flex;
    flex-direction: column;
    animation: ostl-modal-in var(--d-base) var(--ease-out-cubic);
}
.ostl-modal-backdrop[data-closing="true"] .ostl-modal {
    animation: ostl-modal-in var(--d-fast) var(--ease-in-out-cubic) reverse forwards;
}

.ostl-modal--sm { max-width: var(--modal-w-sm); }
.ostl-modal--lg { max-width: var(--modal-w-lg); }
.ostl-modal--fullscreen {
    max-width: none;
    width: 100%;
    height: 100vh;
    max-height: 100vh;
    border-radius: 0;
}

.ostl-modal__header {
    padding: var(--sp-5) var(--sp-6);
    border-bottom: 1px solid var(--color-border-subtle);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--sp-3);
}
.ostl-modal__title {
    font-family: var(--font-display);
    font-size: var(--fs-xl);
    font-weight: var(--fw-bold);
    color: var(--color-text-primary);
    margin: 0;
}
.ostl-modal__close {
    width: 32px; height: 32px;
    display: grid; place-items: center;
    background: transparent;
    border: none;
    border-radius: var(--r-sm);
    color: var(--color-text-muted);
    cursor: pointer;
    transition: background var(--d-fast) var(--ease-smooth),
                color var(--d-fast) var(--ease-smooth);
}
.ostl-modal__close:hover {
    background: var(--color-bg-muted);
    color: var(--color-text-primary);
}
.ostl-modal__body {
    padding: var(--sp-6);
    overflow: auto;
    flex: 1;
    color: var(--color-text-secondary);
    line-height: var(--lh-base);
}
.ostl-modal__footer {
    padding: var(--sp-4) var(--sp-6);
    border-top: 1px solid var(--color-border-subtle);
    display: flex;
    gap: var(--sp-3);
    justify-content: flex-end;
}

/* Body scroll lock */
body.ostl-modal-open {
    overflow: hidden;
    scrollbar-gutter: stable;
}

/* ================================================================== */
/*  TOAST · .ostl-toast                                                */
/* ================================================================== */
.ostl-toast-region {
    position: fixed;
    top: calc(var(--safe-top) + var(--sp-4));
    right: var(--sp-4);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--sp-2);
    width: var(--toast-w);
    max-width: min(var(--toast-w), calc(100% - var(--sp-8)));
    pointer-events: none;
}
.ostl-toast {
    pointer-events: auto;
    background: var(--toast-bg);
    border: 1px solid var(--color-border-default);
    border-left: 4px solid var(--color-accent);
    border-radius: var(--toast-radius);
    padding: var(--sp-3) var(--sp-4);
    box-shadow: var(--shadow-4);
    color: var(--color-text-primary);
    font-size: var(--fs-sm);
    line-height: var(--lh-sm);
    display: flex;
    align-items: flex-start;
    gap: var(--sp-3);
    animation: ostl-toast-in var(--d-base) var(--ease-out-cubic);
}
.ostl-toast[data-closing="true"] {
    animation: ostl-toast-out var(--d-base) var(--ease-in-out-cubic) forwards;
}
.ostl-toast--success { border-left-color: var(--color-success); }
.ostl-toast--warning { border-left-color: var(--color-warning); }
.ostl-toast--danger  { border-left-color: var(--color-danger); }
.ostl-toast--info    { border-left-color: var(--color-info); }

.ostl-toast__icon {
    width: 20px; height: 20px;
    flex-shrink: 0;
    color: var(--color-accent);
}
.ostl-toast--success .ostl-toast__icon { color: var(--color-success); }
.ostl-toast--warning .ostl-toast__icon { color: var(--color-warning); }
.ostl-toast--danger .ostl-toast__icon  { color: var(--color-danger); }
.ostl-toast--info .ostl-toast__icon    { color: var(--color-info); }

.ostl-toast__body { flex: 1; }
.ostl-toast__title {
    font-weight: var(--fw-semi);
    margin-bottom: 2px;
}
.ostl-toast__close {
    background: transparent;
    border: none;
    color: var(--color-text-muted);
    cursor: pointer;
    padding: 2px;
    line-height: 1;
}

/* ================================================================== */
/*  ALERT · .ostl-alert                                                */
/* ================================================================== */
.ostl-alert {
    display: flex;
    align-items: flex-start;
    gap: var(--sp-3);
    padding: var(--sp-3) var(--sp-4);
    border: 1px solid var(--color-border-default);
    border-radius: var(--r-md);
    background: var(--color-bg-elevated);
    color: var(--color-text-primary);
    font-size: var(--fs-sm);
    line-height: var(--lh-sm);
}
.ostl-alert--success {
    background: var(--color-success-bg);
    border-color: var(--color-success-border);
}
.ostl-alert--warning {
    background: var(--color-warning-bg);
    border-color: var(--color-warning-border);
}
.ostl-alert--danger {
    background: var(--color-danger-bg);
    border-color: var(--color-danger-border);
}
.ostl-alert--info {
    background: var(--color-info-bg);
    border-color: var(--color-info-border);
}
.ostl-alert__icon {
    width: 20px; height: 20px;
    flex-shrink: 0;
}
.ostl-alert--success .ostl-alert__icon { color: var(--color-success); }
.ostl-alert--warning .ostl-alert__icon { color: var(--color-warning); }
.ostl-alert--danger  .ostl-alert__icon { color: var(--color-danger); }
.ostl-alert--info    .ostl-alert__icon { color: var(--color-info); }
.ostl-alert__title {
    font-weight: var(--fw-semi);
    margin-bottom: 2px;
}

/* ================================================================== */
/*  BADGE · .ostl-badge                                                */
/* ================================================================== */
.ostl-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--sp-1);
    height: var(--badge-h);
    padding: 0 var(--badge-px);
    font-size: var(--badge-fs);
    font-weight: var(--fw-semi);
    line-height: 1;
    letter-spacing: var(--ls-wide);
    text-transform: uppercase;
    border-radius: var(--badge-radius);
    background: var(--color-bg-elevated);
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border-default);
    box-shadow: var(--shadow-1), var(--card-inset);
    white-space: nowrap;
    transition: border-color var(--d-fast) var(--ease-smooth),
                box-shadow var(--d-fast) var(--ease-smooth),
                transform var(--d-fast) var(--ease-spring);
}
.ostl-badge--accent  { background: var(--color-accent-soft);  color: var(--color-accent);  border-color: var(--color-border-accent); }
.ostl-badge--success { background: var(--color-success-bg);   color: var(--color-success); border-color: var(--color-success-border); }
.ostl-badge--warning { background: var(--color-warning-bg);   color: var(--color-warning); border-color: var(--color-warning-border); }
.ostl-badge--danger  { background: var(--color-danger-bg);    color: var(--color-danger);  border-color: var(--color-danger-border); }
.ostl-badge--info    { background: var(--color-info-bg);      color: var(--color-info);    border-color: var(--color-info-border); }
.ostl-badge--solid   { background: var(--color-accent);       color: var(--color-text-on-accent); border-color: var(--color-accent); }

.ostl-badge__dot {
    width: 6px; height: 6px;
    border-radius: 50%;
    background: currentColor;
}

/* ================================================================== */
/*  AVATAR · .ostl-avatar                                              */
/* ================================================================== */
.ostl-avatar {
    display: inline-grid;
    place-items: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border-default);
    color: var(--color-text-secondary);
    font-size: var(--fs-sm);
    font-weight: var(--fw-semi);
    overflow: hidden;
    flex-shrink: 0;
    user-select: none;
}
.ostl-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.ostl-avatar--sm { width: 28px; height: 28px; font-size: var(--fs-xs); }
.ostl-avatar--lg { width: 56px; height: 56px; font-size: var(--fs-base); }
.ostl-avatar--xl { width: 80px; height: 80px; font-size: var(--fs-lg); }
.ostl-avatar--accent {
    background: var(--color-accent-soft);
    border-color: var(--color-border-accent);
    color: var(--color-accent);
}

/* ================================================================== */
/*  PROGRESS · linear + circular                                       */
/* ================================================================== */
.ostl-progress {
    width: 100%;
    height: 6px;
    background: var(--color-bg-muted);
    border-radius: var(--r-pill);
    overflow: hidden;
    position: relative;
}
.ostl-progress__bar {
    height: 100%;
    background: var(--color-accent);
    border-radius: inherit;
    transition: width var(--d-slower) var(--ease-out-cubic);
    position: relative;
    overflow: hidden;
}
.ostl-progress__bar::after {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,.3), transparent);
    background-size: 200% 100%;
    animation: ostl-shimmer 2.4s linear infinite;
}
.ostl-progress--indeterminate .ostl-progress__bar {
    width: 40% !important;
    animation: ostl-progress-indeterminate 1.6s var(--ease-in-out-cubic) infinite;
}
.ostl-progress--lg { height: 10px; }

/* Circular */
.ostl-progress-circle {
    position: relative;
    width: 96px;
    height: 96px;
}
.ostl-progress-circle svg {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}
.ostl-progress-circle__track,
.ostl-progress-circle__bar {
    fill: none;
    stroke-width: 8;
    cx: 50%; cy: 50%; r: 44%;
}
.ostl-progress-circle__track { stroke: var(--color-bg-muted); }
.ostl-progress-circle__bar {
    stroke: var(--color-accent);
    stroke-linecap: round;
    transition: stroke-dashoffset var(--d-page) var(--ease-out-cubic);
}
.ostl-progress-circle__label {
    position: absolute;
    inset: 0;
    display: grid;
    place-items: center;
    font-family: var(--font-display);
    font-size: var(--fs-xl);
    font-weight: var(--fw-bold);
    color: var(--color-text-primary);
}

/* ================================================================== */
/*  SKELETON · loading                                                 */
/* ================================================================== */
.ostl-skeleton {
    display: block;
    background: linear-gradient(90deg,
        var(--color-bg-muted) 0%,
        var(--color-bg-elevated) 50%,
        var(--color-bg-muted) 100%);
    background-size: 200% 100%;
    border-radius: var(--r-sm);
    animation: ostl-shimmer 1.5s ease-in-out infinite;
}
.ostl-skeleton--text   { height: 1em; margin-block: .25em; }
.ostl-skeleton--title  { height: 1.5em; width: 60%; margin-block: .25em; }
.ostl-skeleton--card   { height: 200px; border-radius: var(--r-lg); }
.ostl-skeleton--avatar { width: 40px; height: 40px; border-radius: 50%; }
.ostl-skeleton--button { height: var(--btn-h-md); width: 120px; border-radius: var(--btn-radius); }

@media (prefers-reduced-motion: reduce) {
    .ostl-skeleton { animation: none; opacity: 0.6; }
}

/* ================================================================== */
/*  SPINNER                                                            */
/* ================================================================== */
.ostl-spinner {
    display: inline-block;
    width: 20px; height: 20px;
    border: 2px solid currentColor;
    border-top-color: transparent;
    border-radius: 50%;
    animation: ostl-spin 700ms linear infinite;
}
.ostl-spinner--sm { width: 14px; height: 14px; }
.ostl-spinner--lg { width: 32px; height: 32px; border-width: 3px; }

/* ================================================================== */
/*  TABS · .ostl-tabs                                                  */
/* ================================================================== */
.ostl-tabs {
    display: flex;
    flex-direction: column;
    gap: var(--sp-4);
}
.ostl-tabs__list {
    display: flex;
    gap: var(--sp-1);
    border-bottom: 1px solid var(--color-border-default);
    padding: 0;
    margin: 0;
    list-style: none;
    overflow-x: auto;
    scrollbar-width: none;
}
.ostl-tabs__list::-webkit-scrollbar { display: none; }
.ostl-tabs__tab {
    background: transparent;
    border: none;
    padding: var(--sp-3) var(--sp-4);
    color: var(--color-text-muted);
    font: inherit;
    font-weight: var(--fw-medium);
    cursor: pointer;
    position: relative;
    white-space: nowrap;
    transition: color var(--d-fast) var(--ease-smooth);
}
.ostl-tabs__tab:hover { color: var(--color-text-secondary); }
.ostl-tabs__tab[aria-selected="true"] {
    color: var(--color-text-primary);
}
.ostl-tabs__tab[aria-selected="true"]::after {
    content: '';
    position: absolute;
    left: var(--sp-4);
    right: var(--sp-4);
    bottom: -1px;
    height: 2px;
    background: var(--color-accent);
    border-radius: 2px;
}
.ostl-tabs__tab:focus-visible {
    box-shadow: var(--focus-ring-shadow);
    border-radius: var(--r-sm);
}
.ostl-tabs__panel[hidden] { display: none; }

/* ================================================================== */
/*  ACCORDION · .ostl-accordion                                        */
/* ================================================================== */
.ostl-accordion {
    display: flex;
    flex-direction: column;
    gap: var(--sp-2);
}
.ostl-accordion__item {
    border: 1px solid var(--color-border-default);
    border-radius: var(--r-md);
    background: var(--color-bg-elevated);
    overflow: hidden;
}
.ostl-accordion__trigger {
    width: 100%;
    background: transparent;
    border: none;
    padding: var(--sp-4) var(--sp-5);
    text-align: left;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--sp-3);
    font: inherit;
    font-weight: var(--fw-semi);
    color: var(--color-text-primary);
    transition: background-color var(--d-fast) var(--ease-smooth);
}
.ostl-accordion__trigger:hover { background: var(--color-bg-muted); }
.ostl-accordion__trigger:focus-visible {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--color-accent);
}
.ostl-accordion__chevron {
    width: 16px; height: 16px;
    color: var(--color-text-muted);
    transition: transform var(--d-base) var(--ease-out-cubic);
    flex-shrink: 0;
}
.ostl-accordion__trigger[aria-expanded="true"] .ostl-accordion__chevron {
    transform: rotate(180deg);
    color: var(--color-accent);
}

/* grid-template-rows technique para height auto animado */
.ostl-accordion__panel {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows var(--d-base) var(--ease-out-cubic);
}
.ostl-accordion__panel[data-open="true"] {
    grid-template-rows: 1fr;
}
.ostl-accordion__panel-inner {
    overflow: hidden;
}
.ostl-accordion__panel-inner > * {
    padding: 0 var(--sp-5) var(--sp-5);
    color: var(--color-text-secondary);
    line-height: var(--lh-base);
}

/* ================================================================== */
/*  PAGINATION · .ostl-pagination                                      */
/* ================================================================== */
.ostl-pagination {
    display: inline-flex;
    align-items: center;
    gap: var(--sp-1);
    list-style: none;
    padding: 0;
    margin: 0;
}
.ostl-pagination__btn {
    min-width: 36px;
    height: 36px;
    padding: 0 var(--sp-2);
    display: inline-grid;
    place-items: center;
    background: transparent;
    border: 1px solid var(--color-border-default);
    border-radius: var(--r-sm);
    color: var(--color-text-secondary);
    font: inherit;
    font-size: var(--fs-sm);
    cursor: pointer;
    text-decoration: none;
    transition: var(--t-all-fast);
}
.ostl-pagination__btn:hover {
    background: var(--color-bg-elevated);
    color: var(--color-text-primary);
    border-color: var(--color-border-strong);
}
.ostl-pagination__btn[aria-current="page"] {
    background: var(--color-accent);
    color: var(--color-text-on-accent);
    border-color: var(--color-accent);
}
.ostl-pagination__btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* ================================================================== */
/*  EMPTY STATE · .ostl-empty                                          */
/* ================================================================== */
.ostl-empty {
    text-align: center;
    padding: var(--sp-12) var(--sp-6);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--sp-4);
    color: var(--color-text-muted);
}
.ostl-empty__illustration {
    width: 120px;
    height: 120px;
    color: var(--color-text-muted);
    opacity: 0.6;
}
.ostl-empty__title {
    font-family: var(--font-display);
    font-size: var(--fs-xl);
    font-weight: var(--fw-bold);
    color: var(--color-text-primary);
    margin: 0;
}
.ostl-empty__body {
    max-width: 380px;
    line-height: var(--lh-base);
    margin: 0;
}

/* ================================================================== */
/*  TOOLTIP · .ostl-tooltip                                            */
/* ================================================================== */
.ostl-tooltip {
    position: relative;
    display: inline-flex;
}
.ostl-tooltip__bubble {
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) translateY(4px);
    background: var(--tooltip-bg);
    color: var(--tooltip-fg);
    font-size: var(--fs-xs);
    line-height: 1.4;
    padding: var(--sp-1) var(--sp-2);
    border-radius: var(--tooltip-radius);
    white-space: nowrap;
    box-shadow: var(--shadow-3);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--d-fast) var(--ease-smooth),
                transform var(--d-fast) var(--ease-spring);
    z-index: var(--z-toast);
}
.ostl-tooltip:hover .ostl-tooltip__bubble,
.ostl-tooltip:focus-within .ostl-tooltip__bubble {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ================================================================== */
/*  DROPDOWN · .ostl-dropdown                                          */
/* ================================================================== */
.ostl-dropdown {
    position: relative;
    display: inline-block;
}
.ostl-dropdown__menu {
    position: absolute;
    top: calc(100% + 4px);
    right: 0;
    min-width: 200px;
    background: var(--dropdown-bg);
    border: 1px solid var(--color-border-default);
    border-radius: var(--dropdown-radius);
    box-shadow: var(--dropdown-shadow);
    padding: var(--sp-1);
    z-index: var(--z-dropdown);
    opacity: 0;
    transform: translateY(-4px);
    pointer-events: none;
    transition: opacity var(--d-fast) var(--ease-smooth),
                transform var(--d-fast) var(--ease-out-cubic);
}
.ostl-dropdown[data-open="true"] .ostl-dropdown__menu {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}
.ostl-dropdown__item {
    display: flex;
    align-items: center;
    gap: var(--sp-2);
    padding: var(--sp-2) var(--sp-3);
    border-radius: var(--r-sm);
    color: var(--color-text-secondary);
    font-size: var(--fs-sm);
    text-decoration: none;
    cursor: pointer;
    transition: var(--t-all-fast);
}
.ostl-dropdown__item:hover {
    background: var(--color-bg-muted);
    color: var(--color-text-primary);
}
.ostl-dropdown__divider {
    height: 1px;
    background: var(--color-border-subtle);
    margin: var(--sp-1) 0;
}

/* ================================================================== */
/*  ICON · standardized                                                */
/* ================================================================== */
.ostl-icon {
    width: 1em;
    height: 1em;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.75;
    stroke-linecap: round;
    stroke-linejoin: round;
    flex-shrink: 0;
    display: inline-block;
    vertical-align: -0.125em;
}
.ostl-icon--sm { width: 14px; height: 14px; }
.ostl-icon--md { width: 20px; height: 20px; }
.ostl-icon--lg { width: 24px; height: 24px; }
.ostl-icon--xl { width: 32px; height: 32px; }

/* ================================================================== */
/*  THEME TOGGLE · pre-styled                                          */
/* ================================================================== */
.ostl-theme-toggle {
    display: inline-grid;
    place-items: center;
    width: 36px;
    height: 36px;
    padding: 0;
    background: transparent;
    border: 1px solid var(--color-border-default);
    border-radius: var(--r-md);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: var(--t-all-fast);
}
.ostl-theme-toggle:hover {
    background: var(--color-bg-elevated);
    color: var(--color-text-primary);
    border-color: var(--color-border-strong);
}
.ostl-theme-toggle:focus-visible {
    outline: none;
    box-shadow: var(--focus-ring-shadow);
}
.ostl-theme-toggle .ostl-theme-toggle__sun  { display: block; }
.ostl-theme-toggle .ostl-theme-toggle__moon { display: none; }
:root[data-theme="light"] .ostl-theme-toggle .ostl-theme-toggle__sun  { display: none; }
:root[data-theme="light"] .ostl-theme-toggle .ostl-theme-toggle__moon { display: block; }

/* ================================================================== */
/*  KBD · keyboard hint                                                */
/* ================================================================== */
.ostl-kbd {
    display: inline-block;
    padding: 2px 6px;
    font-family: var(--font-mono);
    font-size: var(--fs-xs);
    color: var(--color-text-secondary);
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border-strong);
    border-bottom-width: 2px;
    border-radius: 4px;
    line-height: 1;
}

/* ================================================================== */
/*  DIVIDER                                                            */
/* ================================================================== */
.ostl-divider {
    height: 1px;
    background: var(--color-border-default);
    border: none;
    margin: var(--sp-6) 0;
}
.ostl-divider--vertical {
    width: 1px;
    height: auto;
    align-self: stretch;
    margin: 0 var(--sp-3);
}