/* ===================================
   CSS Reset & Base Styles
   =================================== */

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Color Palette */
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-danger: #ef4444;
    --color-danger-dark: #dc2626;
    --color-success: #10b981;
    --color-success-light: #d1fae5;
    --color-error: #f87171;
    --color-error-light: #fee2e2;
    --color-warning: #f59e0b;

    /* Neutral Colors */
    --color-text-primary: #1f2937;
    --color-text-secondary: #6b7280;
    --color-text-light: #9ca3af;
    --color-border: #e5e7eb;
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f9fafb;
    --color-bg-tertiary: #f3f4f6;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --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);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-base: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text-primary);
    background-color: var(--color-bg-secondary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===================================
   Layout
   =================================== */

.container {
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    padding-top: var(--spacing-xl);
}

.title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

.subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    line-height: 1.5;
}

.main-content {
    flex: 1;
    margin-bottom: var(--spacing-2xl);
}

.footer {
    text-align: center;
    padding: var(--spacing-xl) 0;
    border-top: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    margin-top: auto;
}

.footer-links {
    margin-top: var(--spacing-sm);
}

.footer-links a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-base);
}

.footer-links a:hover {
    color: var(--color-primary-dark);
    text-decoration: underline;
}

/* ===================================
   Form Container
   =================================== */

.form-container {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.info-box {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-xl);
    border-left: 4px solid var(--color-primary);
}

.info-icon {
    flex-shrink: 0;
    color: var(--color-primary);
    margin-top: 2px;
}

.info-box p {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* ===================================
   Form Elements
   =================================== */

.delete-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.form-label {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text-primary);
}

.form-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-base);
    font-family: 'Monaco', 'Courier New', monospace;
    color: var(--color-text-primary);
    background: var(--color-bg-primary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    line-height: 1.5;
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-input.error {
    border-color: var(--color-danger);
}

.form-input.error:focus {
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

.error-message {
    font-size: var(--font-size-sm);
    color: var(--color-danger);
    display: none;
}

.error-message.show {
    display: block;
}

/* ===================================
   Checkbox
   =================================== */

.checkbox-container {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
    cursor: pointer;
    position: relative;
    padding-left: 32px;
    user-select: none;
}

.checkbox-container input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

.checkmark {
    position: absolute;
    top: 2px;
    left: 0;
    height: 20px;
    width: 20px;
    background-color: var(--color-bg-primary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
}

.checkbox-container:hover input ~ .checkmark {
    border-color: var(--color-primary);
}

.checkbox-container input:checked ~ .checkmark {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
}

.checkmark::after {
    content: "";
    position: absolute;
    display: none;
}

.checkbox-container input:checked ~ .checkmark::after {
    display: block;
}

.checkbox-container .checkmark::after {
    left: 5px;
    top: 2px;
    width: 4px;
    height: 8px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.checkbox-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* ===================================
   Buttons
   =================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: 600;
    font-family: var(--font-sans);
    text-decoration: none;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-danger {
    background: var(--color-danger);
    color: white;
    width: 100%;
}

.btn-danger:hover:not(:disabled) {
    background: var(--color-danger-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-danger:active:not(:disabled) {
    transform: translateY(0);
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--color-primary-dark);
}

.btn-secondary {
    background: transparent;
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--color-bg-tertiary);
    border-color: var(--color-text-secondary);
}

/* Button Loading State */
.btn[aria-busy="true"] {
    pointer-events: none;
}

.btn[aria-busy="true"] .btn-text {
    opacity: 0;
}

.btn-loader {
    position: absolute;
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
    display: none;
}

.btn[aria-busy="true"] .btn-loader {
    display: block;
}

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

/* ===================================
   Result Containers
   =================================== */

.result-container {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl) var(--spacing-xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
    text-align: center;
    animation: fadeInScale 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.result-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-lg);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.success-icon {
    background: var(--color-success-light);
    color: var(--color-success);
}

.error-icon {
    background: var(--color-error-light);
    color: var(--color-error);
}

.result-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--color-text-primary);
}

.result-message {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.result-action {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    font-style: italic;
}

.result-actions {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

/* ===================================
   Utilities
   =================================== */

[hidden] {
    display: none !important;
}

/* ===================================
   Responsive Design
   =================================== */

@media (max-width: 640px) {
    .container {
        padding: var(--spacing-md);
    }

    .header {
        margin-bottom: var(--spacing-xl);
        padding-top: var(--spacing-md);
    }

    .title {
        font-size: var(--font-size-2xl);
    }

    .subtitle {
        font-size: var(--font-size-base);
    }

    .form-container {
        padding: var(--spacing-lg);
    }

    .result-container {
        padding: var(--spacing-xl) var(--spacing-lg);
    }
}

@media (min-width: 641px) {
    .result-actions {
        flex-direction: row;
        justify-content: center;
    }

    .result-actions .btn {
        min-width: 150px;
    }
}

/* ===================================
   Accessibility
   =================================== */

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

/* Focus visible for keyboard navigation */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000000;
        --color-text-secondary: #000000;
    }
}