:root {
    --app-bg: #f4f7fb;
    --app-surface: #ffffff;
    --app-surface-soft: #f8fafc;
    --app-text: #172033;
    --app-muted: #66758a;
    --app-border: #dce4ef;

    --app-primary: #2563eb;
    --app-primary-hover: #1d4ed8;
    --app-primary-soft: #eaf1ff;

    --app-success: #15803d;
    --app-success-soft: #ecfdf3;

    --app-warning: #b45309;
    --app-warning-soft: #fff7ed;

    --app-danger: #dc2626;
    --app-danger-soft: #fef2f2;

    --app-shadow: 0 16px 42px rgba(15, 23, 42, 0.08);
    --app-shadow-sm: 0 6px 18px rgba(15, 23, 42, 0.06);

    --app-radius: 16px;
    --app-radius-sm: 10px;
}

/* ---------------------------------------------------------
   Base
--------------------------------------------------------- */

html {
    min-height: 100%;
}

body {
    min-width: 320px;
    min-height: 100vh;
    margin: 0;
    background:
        radial-gradient(circle at top left, rgba(37, 99, 235, 0.08), transparent 30rem),
        var(--app-bg);
    color: var(--app-text);
    font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    font-size: 0.95rem;
}

button,
input,
select,
textarea {
    font: inherit;
}

a {
    text-decoration: none;
}

/* ---------------------------------------------------------
   Contenedor y cabecera
--------------------------------------------------------- */

.app-shell {
    width: min(100% - 32px, 1320px);
    margin: 0 auto;
    padding: 36px 0 48px;
}

.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    margin-bottom: 28px;
}

.app-brand {
    display: inline-flex;
    align-items: center;
    gap: 13px;
}

.app-brand__icon {
    display: inline-grid;
    width: 46px;
    height: 46px;
    place-items: center;
    border-radius: 13px;
    background: linear-gradient(135deg, #2563eb, #4f46e5);
    color: #ffffff;
    box-shadow: 0 10px 20px rgba(37, 99, 235, 0.24);
    font-size: 1.35rem;
}

.app-brand__title {
    margin: 0;
    color: var(--app-text);
    font-size: 1.22rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

.app-brand__subtitle {
    margin: 2px 0 0;
    color: var(--app-muted);
    font-size: 0.84rem;
}

.app-header__status {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 8px 12px;
    border: 1px solid #cde9d6;
    border-radius: 999px;
    background: var(--app-success-soft);
    color: var(--app-success);
    font-size: 0.78rem;
    font-weight: 600;
}

.app-header__status i {
    font-size: 0.62rem;
}

/* ---------------------------------------------------------
   Layout principal
--------------------------------------------------------- */

.generator-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(390px, 0.92fr);
    align-items: start;
    gap: 26px;
}

.generator-card {
    overflow: hidden;
    border: 1px solid rgba(220, 228, 239, 0.9);
    border-radius: var(--app-radius);
    background: var(--app-surface);
    box-shadow: var(--app-shadow);
}

.generator-card__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 21px 24px;
    border-bottom: 1px solid var(--app-border);
}

.generator-card__title {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 0;
    color: var(--app-text);
    font-size: 1rem;
    font-weight: 700;
}

.generator-card__title i {
    color: var(--app-primary);
    font-size: 1.08rem;
}

.generator-card__body {
    padding: 24px;
}

/* ---------------------------------------------------------
   Pestañas URL / Wi-Fi
--------------------------------------------------------- */

.generator-tabs {
    display: flex;
    gap: 5px;
    margin-bottom: 25px;
    padding: 5px;
    border-radius: 12px;
    background: #eef3f9;
}

.generator-tabs .nav-link {
    flex: 1;
    padding: 10px 14px;
    border: 0;
    border-radius: 8px;
    color: var(--app-muted);
    font-size: 0.88rem;
    font-weight: 600;
    text-align: center;
    transition: color 0.18s ease, background-color 0.18s ease, box-shadow 0.18s ease;
}

.generator-tabs .nav-link:hover {
    color: var(--app-primary);
}

.generator-tabs .nav-link.active {
    background: #ffffff;
    color: var(--app-primary);
    box-shadow: var(--app-shadow-sm);
}

.generator-tabs .nav-link i {
    margin-right: 7px;
}

/* ---------------------------------------------------------
   Formularios
--------------------------------------------------------- */

.form-label {
    margin-bottom: 7px;
    color: #334155;
    font-size: 0.84rem;
    font-weight: 650;
}

.form-label .required-mark {
    margin-left: 2px;
    color: var(--app-danger);
}

.form-text {
    margin-top: 6px;
    color: var(--app-muted);
    font-size: 0.77rem;
    line-height: 1.45;
}

.form-control,
.form-select {
    min-height: 44px;
    border-color: #cfd9e6;
    border-radius: var(--app-radius-sm);
    color: var(--app-text);
    box-shadow: none;
    font-size: 0.9rem;
}

.form-control::placeholder {
    color: #9aa8ba;
}

.form-control:hover,
.form-select:hover {
    border-color: #aebfd4;
}

.form-control:focus,
.form-select:focus {
    border-color: #7aa5f7;
    box-shadow: 0 0 0 0.22rem rgba(37, 99, 235, 0.13);
}

.form-control.is-invalid,
.form-select.is-invalid {
    border-color: #e56a6a;
    background-image: none;
}

.invalid-feedback {
    color: var(--app-danger);
    font-size: 0.77rem;
    font-weight: 500;
}

.input-group .input-group-text {
    border-color: #cfd9e6;
    border-radius: var(--app-radius-sm) 0 0 var(--app-radius-sm);
    background: #f8fafc;
    color: var(--app-muted);
}

.input-group .form-control {
    border-left: 0;
    border-radius: 0 var(--app-radius-sm) var(--app-radius-sm) 0;
}

/* ---------------------------------------------------------
   Selectores de colores
--------------------------------------------------------- */

.color-control {
    display: flex;
    align-items: center;
    gap: 9px;
}

.color-control input[type="color"] {
    width: 44px;
    min-width: 44px;
    height: 44px;
    padding: 4px;
    border: 1px solid #cfd9e6;
    border-radius: var(--app-radius-sm);
    background: #ffffff;
    cursor: pointer;
}

.color-control input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 0;
}

.color-control input[type="color"]::-webkit-color-swatch {
    border: 0;
    border-radius: 6px;
}

.color-control input[type="color"]::-moz-color-swatch {
    border: 0;
    border-radius: 6px;
}

.color-control .form-control {
    min-width: 0;
}

/* ---------------------------------------------------------
   Tamaños de descarga
--------------------------------------------------------- */

.size-selector {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 8px;
}

.size-selector__option {
    position: relative;
}

.size-selector__option input {
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    pointer-events: none;
}

.size-selector__option label {
    display: flex;
    min-height: 43px;
    align-items: center;
    justify-content: center;
    margin: 0;
    border: 1px solid #cfd9e6;
    border-radius: 9px;
    background: #ffffff;
    color: #526176;
    cursor: pointer;
    font-size: 0.79rem;
    font-weight: 650;
    transition: all 0.18s ease;
}

.size-selector__option label:hover {
    border-color: #91b4f4;
    color: var(--app-primary);
}

.size-selector__option input:checked + label {
    border-color: var(--app-primary);
    background: var(--app-primary-soft);
    color: var(--app-primary);
    box-shadow: inset 0 0 0 1px var(--app-primary);
}

.size-selector__option input:focus-visible + label {
    outline: 3px solid rgba(37, 99, 235, 0.18);
    outline-offset: 2px;
}

/* ---------------------------------------------------------
   Checkbox y switches
--------------------------------------------------------- */

.form-check-input {
    width: 2.25em;
    height: 1.2em;
    margin-top: 0.13em;
    border-color: #b8c5d5;
    cursor: pointer;
    box-shadow: none;
}

.form-check-input:focus {
    border-color: #8eb2f4;
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.13);
}

.form-check-input:checked {
    border-color: var(--app-primary);
    background-color: var(--app-primary);
}

.form-check-label {
    color: #435268;
    cursor: pointer;
    font-size: 0.84rem;
    font-weight: 500;
}

/* ---------------------------------------------------------
   Opciones avanzadas
--------------------------------------------------------- */

.advanced-options {
    margin-top: 23px;
    border: 1px solid var(--app-border);
    border-radius: 12px;
    background: var(--app-surface-soft);
}

.advanced-options .accordion-button {
    padding: 14px 16px;
    border-radius: 12px;
    background: transparent;
    color: #42526a;
    box-shadow: none;
    font-size: 0.87rem;
    font-weight: 650;
}

.advanced-options .accordion-button:not(.collapsed) {
    border-radius: 12px 12px 0 0;
    background: #f0f5ff;
    color: var(--app-primary);
}

.advanced-options .accordion-button::after {
    width: 0.95rem;
    height: 0.95rem;
    background-size: 0.95rem;
}

.advanced-options .accordion-body {
    padding: 4px 16px 17px;
    border-top: 1px solid var(--app-border);
}

.advanced-options__help {
    margin: 0 0 16px;
    color: var(--app-muted);
    font-size: 0.77rem;
    line-height: 1.45;
}

/* ---------------------------------------------------------
   Botón principal
--------------------------------------------------------- */

.generate-button {
    display: inline-flex;
    min-height: 48px;
    align-items: center;
    justify-content: center;
    gap: 9px;
    margin-top: 25px;
    border: 0;
    border-radius: 11px;
    background: linear-gradient(135deg, var(--app-primary), #4f46e5);
    box-shadow: 0 9px 18px rgba(37, 99, 235, 0.22);
    color: #ffffff;
    font-size: 0.91rem;
    font-weight: 700;
    transition: transform 0.18s ease, box-shadow 0.18s ease, filter 0.18s ease;
}

.generate-button:hover {
    background: linear-gradient(135deg, var(--app-primary-hover), #4338ca);
    box-shadow: 0 12px 23px rgba(37, 99, 235, 0.29);
    color: #ffffff;
    transform: translateY(-1px);
}

.generate-button:active {
    transform: translateY(0);
}

.generate-button:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.24);
    outline-offset: 3px;
}

.generate-button:disabled {
    cursor: not-allowed;
    opacity: 0.67;
    transform: none;
}

/* ---------------------------------------------------------
   Estados: cambios pendientes, errores y éxito
--------------------------------------------------------- */

.pending-changes {
    display: none;
    align-items: center;
    gap: 8px;
    margin-top: 16px;
    padding: 10px 12px;
    border: 1px solid #fed7aa;
    border-radius: 10px;
    background: var(--app-warning-soft);
    color: var(--app-warning);
    font-size: 0.79rem;
    font-weight: 500;
}

.pending-changes.is-visible {
    display: flex;
}

.pending-changes i {
    font-size: 0.96rem;
}

.app-alert {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    margin: 0 0 19px;
    padding: 12px 14px;
    border: 1px solid transparent;
    border-radius: 11px;
    font-size: 0.83rem;
    line-height: 1.45;
}

.app-alert i {
    margin-top: 1px;
    font-size: 1rem;
}

.app-alert--error {
    border-color: #fecaca;
    background: var(--app-danger-soft);
    color: #b91c1c;
}

.app-alert--success {
    border-color: #bbf7d0;
    background: var(--app-success-soft);
    color: #166534;
}

/* ---------------------------------------------------------
   Panel de preview
--------------------------------------------------------- */

.preview-card {
    position: sticky;
    top: 22px;
}

.preview-card .generator-card__body {
    display: flex;
    min-height: 610px;
    flex-direction: column;
}

.preview-status {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 6px 10px;
    border-radius: 999px;
    background: #eef3f9;
    color: #64748b;
    font-size: 0.74rem;
    font-weight: 650;
}

.preview-status i {
    font-size: 0.72rem;
}

.preview-status--ready {
    background: var(--app-success-soft);
    color: var(--app-success);
}

.preview-status--pending {
    background: var(--app-warning-soft);
    color: var(--app-warning);
}

.qr-preview-area {
    display: grid;
    min-height: 365px;
    flex: 1;
    place-items: center;
    margin-bottom: 20px;
    padding: 26px;
    border: 1px dashed #cbd7e6;
    border-radius: 14px;
    background-color: #f8fafc;
}

.qr-preview-area--transparent {
    background-color: #ffffff;
    background-image:
        linear-gradient(45deg, #edf1f6 25%, transparent 25%),
        linear-gradient(-45deg, #edf1f6 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #edf1f6 75%),
        linear-gradient(-45deg, transparent 75%, #edf1f6 75%);
    background-position: 0 0, 0 10px, 10px -10px, -10px 0;
    background-size: 20px 20px;
}

.qr-preview-placeholder {
    max-width: 275px;
    color: var(--app-muted);
    text-align: center;
}

.qr-preview-placeholder__icon {
    display: inline-grid;
    width: 65px;
    height: 65px;
    place-items: center;
    margin-bottom: 14px;
    border-radius: 17px;
    background: #eaf1ff;
    color: var(--app-primary);
    font-size: 1.8rem;
}

.qr-preview-placeholder p {
    margin: 0;
    font-size: 0.84rem;
    line-height: 1.5;
}

.qr-preview-image {
    display: block;
    width: min(100%, 420px);
    height: auto;
    max-height: 420px;
    object-fit: contain;
    image-rendering: pixelated;
}

.preview-meta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-bottom: 21px;
    color: var(--app-muted);
    font-size: 0.79rem;
    font-weight: 500;
}

.preview-meta i {
    color: var(--app-primary);
}

/* ---------------------------------------------------------
   Descargas
--------------------------------------------------------- */

.download-section {
    margin-top: auto;
    padding-top: 21px;
    border-top: 1px solid var(--app-border);
}

.download-section__title {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 0 0 13px;
    color: #435268;
    font-size: 0.82rem;
    font-weight: 700;
}

.download-section__title i {
    color: var(--app-primary);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
}

.download-button {
    display: inline-flex;
    min-height: 43px;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: 1px solid #cfd9e6;
    border-radius: 10px;
    background: #ffffff;
    color: #435268;
    font-size: 0.8rem;
    font-weight: 650;
    transition: all 0.18s ease;
}

.download-button:hover:not(.is-disabled) {
    border-color: #8eb2f4;
    background: #f6f9ff;
    color: var(--app-primary);
}

.download-button i {
    color: var(--app-primary);
    font-size: 0.96rem;
}

.download-button.is-disabled,
.download-button[aria-disabled="true"] {
    cursor: not-allowed;
    opacity: 0.48;
    pointer-events: none;
}

/* ---------------------------------------------------------
   Pie
--------------------------------------------------------- */

.app-footer {
    margin-top: 24px;
    color: #7b899c;
    font-size: 0.75rem;
    text-align: center;
}

.app-footer i {
    margin-right: 4px;
    color: var(--app-primary);
}

/* ---------------------------------------------------------
   Responsive
--------------------------------------------------------- */

@media (max-width: 991.98px) {
    .generator-layout {
        grid-template-columns: 1fr;
    }

    .preview-card {
        position: static;
    }

    .preview-card .generator-card__body {
        min-height: auto;
    }

    .qr-preview-area {
        min-height: 330px;
    }
}

@media (max-width: 575.98px) {
    .app-shell {
        width: min(100% - 20px, 1320px);
        padding-top: 20px;
        padding-bottom: 28px;
    }

    .app-header {
        align-items: flex-start;
        flex-direction: column;
        gap: 14px;
        margin-bottom: 20px;
    }

    .app-header__status {
        align-self: flex-start;
    }

    .generator-card__header,
    .generator-card__body {
        padding-right: 16px;
        padding-left: 16px;
    }

    .generator-card__header {
        padding-top: 17px;
        padding-bottom: 17px;
    }

    .generator-card__body {
        padding-top: 18px;
        padding-bottom: 18px;
    }

    .size-selector {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .qr-preview-area {
        min-height: 280px;
        padding: 18px;
    }

    .qr-preview-image {
        width: min(100%, 280px);
        max-height: 280px;
    }

    .download-grid {
        grid-template-columns: 1fr;
    }
}