/**
 * Modern E-Commerce UI Kit
 * Comprehensive form elements and components
 */

/* ===========================
   CSS VARIABLES
   =========================== */

:root {
    /* Spacing Scale */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    --spacing-3xl: 64px;
    
    /* Font Sizes */
    --font-xs: 12px;
    --font-sm: 13px;
    --font-base: 14px;
    --font-md: 16px;
    --font-lg: 18px;
    --font-xl: 20px;
    --font-2xl: 24px;
    --font-3xl: 30px;
    --font-4xl: 36px;
    
    /* Font Weights */
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;
    
    /* Line Heights */
    --leading-tight: 1.25;
    --leading-normal: 1.5;
    --leading-relaxed: 1.75;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-base: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Focus Ring */
    --focus-ring: 0 0 0 3px rgba(37, 99, 235, 0.1);
    --focus-ring-error: 0 0 0 3px rgba(239, 68, 68, 0.1);
    --focus-ring-success: 0 0 0 3px rgba(16, 185, 129, 0.1);
}

/* ===========================
   FORM ELEMENTS BASE
   =========================== */

/* Form Group */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group:last-child {
    margin-bottom: 0;
}

/* Form Label */
.form-label {
    display: block;
    font-size: var(--font-base);
    font-weight: var(--font-semibold);
    color: var(--heading-color);
    margin-bottom: var(--spacing-sm);
    line-height: var(--leading-normal);
}

.form-label.required::after {
    content: '*';
    color: #ef4444;
    margin-left: var(--spacing-xs);
}

.form-label-inline {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

/* Form Description */
.form-description {
    display: block;
    font-size: var(--font-sm);
    color: #6b7280;
    margin-top: var(--spacing-xs);
    line-height: var(--leading-normal);
}

/* Form Error */
.form-error {
    display: block;
    font-size: var(--font-sm);
    color: #ef4444;
    margin-top: var(--spacing-xs);
    line-height: var(--leading-normal);
}

.form-error::before {
    content: '⚠ ';
}

/* Form Success */
.form-success {
    display: block;
    font-size: var(--font-sm);
    color: #10b981;
    margin-top: var(--spacing-xs);
    line-height: var(--leading-normal);
}

.form-success::before {
    content: '✓ ';
}

/* ===========================
   TEXT INPUTS
   =========================== */

.form-input,
.form-textarea,
.form-select {
    width: 100%;
    padding: 14px 16px;
    font-size: var(--font-md);
    font-family: inherit;
    line-height: var(--leading-normal);
    color: var(--text-color);
    background-color: #ffffff;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-medium);
    transition: all var(--transition-base);
    appearance: none;
}

.form-input:hover,
.form-textarea:hover,
.form-select:hover {
    border-color: #d1d5db;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: var(--focus-ring);
}

.form-input:disabled,
.form-textarea:disabled,
.form-select:disabled {
    background-color: var(--secondary-bg);
    color: #9ca3af;
    cursor: not-allowed;
    opacity: 0.6;
}

.form-input.error,
.form-textarea.error,
.form-select.error {
    border-color: #ef4444;
}

.form-input.error:focus,
.form-textarea.error:focus,
.form-select.error:focus {
    box-shadow: var(--focus-ring-error);
}

.form-input.success,
.form-textarea.success,
.form-select.success {
    border-color: #10b981;
}

.form-input.success:focus,
.form-textarea.success:focus,
.form-select.success:focus {
    box-shadow: var(--focus-ring-success);
}

/* Input Sizes */
.form-input-sm {
    padding: 10px 12px;
    font-size: var(--font-sm);
}

.form-input-lg {
    padding: 16px 20px;
    font-size: var(--font-lg);
}

/* Textarea */
.form-textarea {
    min-height: 120px;
    resize: vertical;
}

.form-textarea-sm {
    min-height: 80px;
}

.form-textarea-lg {
    min-height: 180px;
}

/* ===========================
   SELECT DROPDOWN
   =========================== */

.form-select {
    padding-right: 40px;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3E%3Cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3E%3C/svg%3E");
    background-position: right 12px center;
    background-repeat: no-repeat;
    background-size: 20px;
    cursor: pointer;
}

.form-select:focus {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3E%3Cpath stroke='%232563eb' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3E%3C/svg%3E");
}

/* ===========================
   CHECKBOX & RADIO
   =========================== */

.form-checkbox,
.form-radio {
    position: relative;
    display: inline-flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.form-checkbox input[type="checkbox"],
.form-radio input[type="radio"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.form-checkbox-box,
.form-radio-box {
    position: relative;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    background-color: #ffffff;
    transition: all var(--transition-base);
    flex-shrink: 0;
}

.form-checkbox-box {
    border-radius: var(--border-radius-small);
}

.form-radio-box {
    border-radius: 50%;
}

.form-checkbox:hover .form-checkbox-box,
.form-radio:hover .form-radio-box {
    border-color: var(--primary-color);
}

.form-checkbox input:checked ~ .form-checkbox-box,
.form-radio input:checked ~ .form-radio-box {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.form-checkbox input:focus ~ .form-checkbox-box,
.form-radio input:focus ~ .form-radio-box {
    box-shadow: var(--focus-ring);
}

.form-checkbox input:disabled ~ .form-checkbox-box,
.form-radio input:disabled ~ .form-radio-box {
    background-color: var(--secondary-bg);
    border-color: #d1d5db;
    cursor: not-allowed;
    opacity: 0.6;
}

/* Checkbox Checkmark */
.form-checkbox-box::after {
    content: '';
    position: absolute;
    display: none;
    left: 5px;
    top: 2px;
    width: 6px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.form-checkbox input:checked ~ .form-checkbox-box::after {
    display: block;
}

/* Radio Dot */
.form-radio-box::after {
    content: '';
    position: absolute;
    display: none;
    left: 50%;
    top: 50%;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: white;
    transform: translate(-50%, -50%);
}

.form-radio input:checked ~ .form-radio-box::after {
    display: block;
}

/* Checkbox/Radio Label */
.form-checkbox-label,
.form-radio-label {
    margin-left: var(--spacing-sm);
    font-size: var(--font-base);
    color: var(--text-color);
    line-height: var(--leading-normal);
}

/* Large Checkbox/Radio */
.form-checkbox-lg .form-checkbox-box,
.form-radio-lg .form-radio-box {
    width: 24px;
    height: 24px;
}

.form-checkbox-lg .form-checkbox-box::after {
    left: 7px;
    top: 3px;
    width: 7px;
    height: 12px;
}

.form-radio-lg .form-radio-box::after {
    width: 10px;
    height: 10px;
}

/* ===========================
   TOGGLE SWITCH
   =========================== */

.form-toggle {
    position: relative;
    display: inline-flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.form-toggle input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.form-toggle-switch {
    position: relative;
    width: 48px;
    height: 26px;
    background-color: #d1d5db;
    border-radius: 13px;
    transition: background-color var(--transition-base);
    flex-shrink: 0;
}

.form-toggle-switch::after {
    content: '';
    position: absolute;
    top: 3px;
    left: 3px;
    width: 20px;
    height: 20px;
    background-color: white;
    border-radius: 50%;
    transition: transform var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.form-toggle:hover .form-toggle-switch {
    background-color: #9ca3af;
}

.form-toggle input:checked ~ .form-toggle-switch {
    background-color: var(--primary-color);
}

.form-toggle input:checked ~ .form-toggle-switch::after {
    transform: translateX(22px);
}

.form-toggle input:focus ~ .form-toggle-switch {
    box-shadow: var(--focus-ring);
}

.form-toggle input:disabled ~ .form-toggle-switch {
    opacity: 0.5;
    cursor: not-allowed;
}

.form-toggle-label {
    margin-left: var(--spacing-md);
    font-size: var(--font-base);
    color: var(--text-color);
}

/* Large Toggle */
.form-toggle-lg .form-toggle-switch {
    width: 56px;
    height: 30px;
}

.form-toggle-lg .form-toggle-switch::after {
    width: 24px;
    height: 24px;
}

.form-toggle-lg input:checked ~ .form-toggle-switch::after {
    transform: translateX(26px);
}

/* ===========================
   INPUT GROUPS
   =========================== */

.input-group {
    display: flex;
    width: 100%;
}

.input-group .form-input {
    border-radius: 0;
}

.input-group .form-input:first-child {
    border-top-left-radius: var(--border-radius-medium);
    border-bottom-left-radius: var(--border-radius-medium);
}

.input-group .form-input:last-child {
    border-top-right-radius: var(--border-radius-medium);
    border-bottom-right-radius: var(--border-radius-medium);
}

.input-group-prepend,
.input-group-append {
    display: flex;
    align-items: center;
    padding: 0 16px;
    font-size: var(--font-base);
    font-weight: var(--font-medium);
    color: #6b7280;
    background-color: var(--secondary-bg);
    border: 2px solid var(--border-color);
    white-space: nowrap;
}

.input-group-prepend {
    border-right: none;
    border-top-left-radius: var(--border-radius-medium);
    border-bottom-left-radius: var(--border-radius-medium);
}

.input-group-append {
    border-left: none;
    border-top-right-radius: var(--border-radius-medium);
    border-bottom-right-radius: var(--border-radius-medium);
}

.input-group .form-input:not(:first-child) {
    border-left: none;
}

.input-group .form-input:not(:last-child) {
    border-right: none;
}

/* ===========================
   BUTTONS
   =========================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 14px 24px;
    font-size: var(--font-md);
    font-weight: var(--font-semibold);
    line-height: var(--leading-tight);
    text-align: center;
    text-decoration: none;
    white-space: nowrap;
    border: 2px solid transparent;
    border-radius: var(--border-radius-medium);
    cursor: pointer;
    transition: all var(--transition-base);
    user-select: none;
}

.btn:focus {
    outline: none;
    box-shadow: var(--focus-ring);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

/* Button Variants */
.btn-primary {
    color: white;
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: #1d4ed8;
    border-color: #1d4ed8;
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    color: var(--text-color);
    background-color: var(--secondary-bg);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background-color: #e5e7eb;
    border-color: #d1d5db;
}

.btn-accent {
    color: white;
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

.btn-accent:hover {
    background-color: #d97706;
    border-color: #d97706;
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-success {
    color: white;
    background-color: #10b981;
    border-color: #10b981;
}

.btn-success:hover {
    background-color: #059669;
    border-color: #059669;
    color: white;
}

.btn-danger {
    color: white;
    background-color: #ef4444;
    border-color: #ef4444;
}

.btn-danger:hover {
    background-color: #dc2626;
    border-color: #dc2626;
    color: white;
}

.btn-outline {
    color: var(--primary-color);
    background-color: transparent;
    border-color: var(--primary-color);
}

.btn-outline:hover {
    color: white;
    background-color: var(--primary-color);
}

.btn-ghost {
    color: var(--text-color);
    background-color: transparent;
    border-color: transparent;
}

.btn-ghost:hover {
    background-color: var(--secondary-bg);
}

/* Button Sizes */
.btn-sm {
    padding: 10px 16px;
    font-size: var(--font-sm);
}

.btn-lg {
    padding: 16px 32px;
    font-size: var(--font-lg);
}

.btn-xl {
    padding: 20px 40px;
    font-size: var(--font-xl);
}

/* Button Block */
.btn-block {
    display: flex;
    width: 100%;
}

/* Button Group */
.btn-group {
    display: inline-flex;
    gap: var(--spacing-sm);
}

.btn-group .btn {
    margin: 0;
}

/* ===========================
   ALERTS & MESSAGES
   =========================== */

.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius-medium);
    border: 2px solid;
    margin-bottom: var(--spacing-lg);
}

.alert-info {
    color: #1e40af;
    background-color: #dbeafe;
    border-color: #93c5fd;
}

.alert-success {
    color: #065f46;
    background-color: #d1fae5;
    border-color: #6ee7b7;
}

.alert-warning {
    color: #92400e;
    background-color: #fef3c7;
    border-color: #fcd34d;
}

.alert-error {
    color: #991b1b;
    background-color: #fee2e2;
    border-color: #fca5a5;
}

.alert-title {
    font-weight: var(--font-semibold);
    margin-bottom: var(--spacing-xs);
}

/* ===========================
   BADGES
   =========================== */

.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    font-size: var(--font-xs);
    font-weight: var(--font-semibold);
    line-height: 1;
    border-radius: var(--border-radius-small);
}

.badge-primary {
    color: white;
    background-color: var(--primary-color);
}

.badge-secondary {
    color: var(--text-color);
    background-color: var(--secondary-bg);
}

.badge-success {
    color: white;
    background-color: #10b981;
}

.badge-warning {
    color: #92400e;
    background-color: #fbbf24;
}

.badge-danger {
    color: white;
    background-color: #ef4444;
}

/* ===========================
   CARDS
   =========================== */

.card {
    background-color: white;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-large);
    overflow: hidden;
}

.card-header {
    padding: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
    background-color: var(--secondary-bg);
}

.card-body {
    padding: var(--spacing-lg);
}

.card-footer {
    padding: var(--spacing-lg);
    border-top: 2px solid var(--border-color);
    background-color: var(--secondary-bg);
}

.card-title {
    font-size: var(--font-xl);
    font-weight: var(--font-bold);
    margin: 0 0 var(--spacing-sm);
    color: var(--heading-color);
}

/* ===========================
   LOADING SPINNER
   =========================== */

.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(0, 0, 0, 0.1);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.spinner-lg {
    width: 40px;
    height: 40px;
    border-width: 4px;
}

/* ===========================
   UTILITY CLASSES
   =========================== */

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.w-full { width: 100%; }
.w-auto { width: auto; }

.d-block { display: block; }
.d-inline { display: inline; }
.d-inline-block { display: inline-block; }
.d-flex { display: flex; }
.d-none { display: none; }