/* ===========================================
   Proof It - Modern Text Improvement Tool
   Clean, minimal, and focused design
   =========================================== */

/* ---------- CSS Custom Properties ---------- */
:root {
    /* Colors - Warm, friendly palette */
    --color-bg: #fafafa;
    --color-surface: #ffffff;
    --color-text: #1a1a2e;
    --color-text-secondary: #64648c;
    --color-text-muted: #9898b0;

    /* Primary accent - Friendly indigo/purple */
    --color-primary: #6366f1;
    --color-primary-hover: #4f46e5;
    --color-primary-light: #e0e7ff;
    --color-primary-subtle: #f5f5ff;

    /* Feedback colors */
    --color-success: #10b981;
    --color-success-light: #d1fae5;
    --color-error: #ef4444;
    --color-error-light: #fee2e2;

    /* Borders and shadows */
    --color-border: #e5e5ef;
    --color-border-focus: #6366f1;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08);
    --shadow-focus: 0 0 0 3px rgba(99, 102, 241, 0.2);

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', monospace;

    /* Spacing scale */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;

    /* Border radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    min-height: 100vh;
}

/* ---------- Accessibility ---------- */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* ---------- Layout ---------- */
.app-container {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

.bg-gradient {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 50vh;
    background: linear-gradient(135deg, var(--color-primary-subtle) 0%, var(--color-bg) 100%);
    pointer-events: none;
    z-index: -1;
}

/* ---------- Header ---------- */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md) var(--space-lg);
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-weight: 600;
    font-size: 1.125rem;
    color: var(--color-text);
}

.logo-icon {
    font-size: 1.25rem;
}

.privacy-badge {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    background: var(--color-surface);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-full);
    border: 1px solid var(--color-border);
}

.privacy-icon {
    font-size: 0.75rem;
}

/* ---------- Main Content ---------- */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--space-lg);
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}

/* ---------- Hero Section ---------- */
.hero {
    text-align: center;
    margin-bottom: var(--space-xl);
}

.hero-title {
    font-size: clamp(1.75rem, 5vw, 2.5rem);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.0625rem;
    color: var(--color-text-secondary);
    max-width: 400px;
    margin: 0 auto;
}

/* ---------- Mode Selector ---------- */
.mode-selector {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    justify-content: center;
    margin-bottom: var(--space-lg);
}

.mode-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.mode-btn:hover {
    color: var(--color-text);
    border-color: var(--color-text-muted);
}

.mode-btn.active {
    color: var(--color-primary);
    background: var(--color-primary-light);
    border-color: var(--color-primary);
}

.mode-btn:focus-visible {
    box-shadow: var(--shadow-focus);
}

.mode-icon {
    font-size: 1rem;
}

/* ---------- Editor Section ---------- */
.editor-section {
    width: 100%;
}

.editor-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.editor-wrapper {
    position: relative;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.editor-wrapper:focus-within {
    border-color: var(--color-border-focus);
    box-shadow: var(--shadow-md), var(--shadow-focus);
}

.text-input {
    width: 100%;
    min-height: 200px;
    padding: var(--space-lg);
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--color-text);
    background: transparent;
    border: none;
    resize: vertical;
    outline: none;
}

.text-input::placeholder {
    color: var(--color-text-muted);
}

.input-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-sm) var(--space-lg);
    border-top: 1px solid var(--color-border);
    background: var(--color-bg);
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
}

.input-hint {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.char-count {
    font-size: 0.8125rem;
    font-family: var(--font-mono);
    color: var(--color-text-muted);
}

.char-count.warning {
    color: var(--color-error);
}

/* ---------- Action Button ---------- */
.improve-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: var(--space-md) var(--space-lg);
    font-size: 1.0625rem;
    font-weight: 600;
    color: white;
    background: var(--color-primary);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.improve-btn:hover:not(:disabled) {
    background: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

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

.improve-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.improve-btn:focus-visible {
    box-shadow: var(--shadow-focus);
}

.improve-btn .btn-loading {
    display: none;
}

.improve-btn.loading .btn-text {
    display: none;
}

.improve-btn.loading .btn-loading {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

/* Spinner animation */
.spinner {
    width: 18px;
    height: 18px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* ---------- Result Section ---------- */
.result-section {
    margin-top: var(--space-xl);
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-section.hidden {
    display: none;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-md);
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.result-title {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-success);
}

.result-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: var(--color-success-light);
    border-radius: 50%;
    font-size: 0.875rem;
}

.result-actions {
    display: flex;
    gap: var(--space-sm);
}

.action-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.action-btn:hover {
    color: var(--color-text);
    border-color: var(--color-text-muted);
}

.action-btn.primary {
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.action-btn.primary:hover {
    background: var(--color-primary-light);
}

.action-btn.copied {
    color: var(--color-success);
    border-color: var(--color-success);
    background: var(--color-success-light);
}

/* ---------- Result Output ---------- */
.result-output {
    position: relative;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.improved-text {
    min-height: 120px;
    padding: var(--space-lg);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--color-text);
    outline: none;
}

.improved-text:focus {
    background: var(--color-primary-subtle);
}

.edit-hint {
    position: absolute;
    bottom: var(--space-sm);
    right: var(--space-md);
    font-size: 0.75rem;
    color: var(--color-text-muted);
    pointer-events: none;
    opacity: 0.7;
}

/* ---------- Comparison View ---------- */
.comparison-view {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: var(--space-md);
    margin-top: var(--space-lg);
    padding: var(--space-lg);
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
}

.comparison-view.hidden {
    display: none;
}

.comparison-column {
    min-width: 0;
}

.comparison-label {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-sm);
}

.comparison-text {
    font-size: 0.9375rem;
    line-height: 1.6;
    color: var(--color-text-secondary);
    white-space: pre-wrap;
    word-break: break-word;
}

.comparison-divider {
    width: 1px;
    background: var(--color-border);
}

/* ---------- Reset Button ---------- */
.reset-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    margin-top: var(--space-lg);
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-muted);
    background: transparent;
    border: none;
    cursor: pointer;
    transition: color var(--transition-fast);
}

.reset-btn:hover {
    color: var(--color-text);
}

/* ---------- Error Message ---------- */
.error-message {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-top: var(--space-md);
    padding: var(--space-md);
    background: var(--color-error-light);
    border: 1px solid var(--color-error);
    border-radius: var(--radius-md);
    color: var(--color-error);
    font-size: 0.9375rem;
}

.error-message.hidden {
    display: none;
}

/* ---------- Footer ---------- */
.footer {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-lg);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.footer-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: var(--color-primary);
}

/* ---------- Hidden Utility ---------- */
.hidden {
    display: none !important;
}

/* ---------- Responsive Design ---------- */
@media (max-width: 640px) {
    .header {
        padding: var(--space-md);
    }

    .privacy-badge {
        display: none;
    }

    .main-content {
        padding: var(--space-md);
    }

    .hero {
        margin-bottom: var(--space-lg);
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .mode-selector {
        gap: var(--space-xs);
    }

    .mode-btn {
        padding: var(--space-xs) var(--space-sm);
        font-size: 0.8125rem;
    }

    .mode-btn .mode-icon {
        display: none;
    }

    .text-input {
        min-height: 160px;
        padding: var(--space-md);
    }

    .input-footer {
        flex-direction: column;
        gap: var(--space-xs);
        align-items: flex-start;
        padding: var(--space-sm) var(--space-md);
    }

    .comparison-view {
        grid-template-columns: 1fr;
        gap: var(--space-lg);
    }

    .comparison-divider {
        display: none;
    }

    .result-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .footer {
        flex-direction: column;
        gap: var(--space-sm);
    }
}

/* ---------- Dark Mode Support ---------- */
@media (prefers-color-scheme: dark) {
    :root {
        --color-bg: #0f0f1a;
        --color-surface: #1a1a2e;
        --color-text: #f0f0f5;
        --color-text-secondary: #a0a0b8;
        --color-text-muted: #6a6a80;
        --color-border: #2a2a40;
        --color-primary-subtle: #1a1a30;
        --color-primary-light: #2a2a50;
        --color-success-light: #0a2a20;
        --color-error-light: #2a1515;
    }

    .bg-gradient {
        background: linear-gradient(135deg, #1a1a30 0%, var(--color-bg) 100%);
    }
}

/* ---------- Print Styles ---------- */
@media print {
    .header,
    .mode-selector,
    .improve-btn,
    .result-actions,
    .reset-btn,
    .footer,
    .bg-gradient {
        display: none;
    }

    .result-section {
        margin: 0;
    }

    .improved-text {
        border: none;
        padding: 0;
    }
}

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