/* ===== CSS VARIABLES (Google/Gemini Style) ===== */
:root {
    --primary: #1a73e8;
    --primary-hover: #1557b0;
    --primary-light: #e8f0fe;
    --secondary: #34a853;
    --secondary-hover: #2d7a3d;
    --success: #137333;
    --error: #d93025;
    --warning: #f9ab00;
    
    /* Google Color Palette */
    --blue-50: #e8f0fe;
    --blue-500: #1a73e8;
    --blue-600: #1557b0;
    --green-500: #34a853;
    --red-500: #d93025;
    --grey-50: #f8f9fa;
    --grey-100: #f1f3f4;
    --grey-200: #e8eaed;
    --grey-300: #dadce0;
    --grey-500: #9aa0a6;
    --grey-700: #5f6368;
    --grey-900: #202124;
    
    /* Semantic Colors */
    --bg-primary: #ffffff;
    --bg-secondary: var(--grey-50);
    --bg-tertiary: var(--grey-100);
    --text-primary: var(--grey-900);
    --text-secondary: var(--grey-700);
    --text-muted: var(--grey-500);
    --border: var(--grey-200);
    --border-focus: var(--blue-500);
    --shadow: 0 1px 3px rgba(60,64,67,0.3), 0 4px 8px 3px rgba(60,64,67,0.15);
    --shadow-hover: 0 2px 6px 2px rgba(60,64,67,0.15), 0 8px 24px 4px rgba(60,64,67,0.15);
    
    /* Typography */
    --font-family: 'Google Sans', 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-xs: 12px;
    --font-sm: 14px;
    --font-base: 16px;
    --font-lg: 18px;
    --font-xl: 20px;
    --font-2xl: 24px;
    --font-3xl: 30px;
    --font-4xl: 36px;
    
    /* Spacing (Google 8px grid) */
    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 20px;
    --space-6: 24px;
    --space-8: 32px;
    --space-10: 40px;
    --space-12: 48px;
    --space-16: 64px;
    
    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-2xl: 20px;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 0.15s cubic-bezier(0.2, 0, 0, 1);
    --transition: 0.2s cubic-bezier(0.2, 0, 0, 1);
    --transition-slow: 0.3s cubic-bezier(0.2, 0, 0, 1);
}

/* ===== BASE STYLES ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-base);
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* ===== DESKTOP ONLY ELEMENTS ===== */
.desktop-only {
    display: block;
}

@media (max-width: 768px) {
    .desktop-only {
        display: none !important;
    }
}

/* ===== HEADER ===== */
.header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    padding: var(--space-5) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-6);
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-size: var(--font-xl);
    font-weight: 500;
    color: var(--text-primary);
}

.logo-icon {
    font-size: var(--font-2xl);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-2px); }
}

/* ===== MAIN CONTENT ===== */
.main-container {
    flex: 1;
    padding: var(--space-8) var(--space-6);
}

.content-wrapper {
    max-width: 800px;
    margin: 0 auto;
}

/* ===== HERO SECTION ===== */
.hero-section {
    text-align: center;
    margin-bottom: var(--space-12);
}

.hero-title {
    font-size: var(--font-4xl);
    font-weight: 400;
    margin-bottom: var(--space-3);
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.hero-subtitle {
    font-size: var(--font-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
    font-weight: 400;
}

/* ===== GENERATOR CARD ===== */
.generator-card {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    transition: all var(--transition);
    margin-bottom: var(--space-8);
}

.generator-card:hover {
    box-shadow: var(--shadow-hover);
}

.generator-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-8);
}

/* ===== INPUT SECTIONS ===== */
.input-section {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.input-label {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-weight: 500;
    color: var(--text-primary);
    font-size: var(--font-sm);
}

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

.label-required {
    color: var(--error);
    font-weight: 500;
}

.textarea-wrapper {
    position: relative;
}

.prompt-input {
    width: 100%;
    padding: var(--space-4);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: var(--font-sm);
    line-height: 1.5;
    resize: vertical;
    min-height: 120px;
    max-height: 300px;
    transition: all var(--transition-fast);
    outline: none;
}

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

.prompt-input:focus {
    border-color: var(--border-focus);
    box-shadow: inset 0 0 0 1px var(--border-focus);
}

.char-counter {
    position: absolute;
    bottom: var(--space-2);
    right: var(--space-3);
    font-size: var(--font-xs);
    color: var(--text-secondary);
    background: var(--bg-primary);
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-sm);
    box-shadow: 0 1px 3px rgba(60,64,67,0.3);
    border: 1px solid var(--border);
}

.char-counter.warning {
    color: var(--warning);
    border-color: var(--warning);
}

.char-counter.error {
    color: var(--error);
    border-color: var(--error);
}

.select-wrapper {
    position: relative;
}

.size-select {
    width: 100%;
    height: 56px;
    padding: var(--space-4);
    padding-right: var(--space-12);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: var(--font-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    appearance: none;
    outline: none;
}

.size-select:focus {
    border-color: var(--border-focus);
    box-shadow: inset 0 0 0 1px var(--border-focus);
}

.select-arrow {
    position: absolute;
    right: var(--space-4);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    pointer-events: none;
    font-size: var(--font-lg);
    transition: all var(--transition-fast);
}

.size-select:focus + .select-arrow {
    color: var(--border-focus);
    transform: translateY(-50%) rotate(180deg);
}

.input-help {
    font-size: var(--font-xs);
    color: var(--text-secondary);
    margin-top: var(--space-1);
}

/* ===== GENERATE BUTTON ===== */
.generate-btn {
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: var(--space-4) var(--space-6);
    font-family: inherit;
    font-size: var(--font-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    letter-spacing: 0.25px;
}

.generate-btn:hover:not(:disabled) {
    background: var(--primary-hover);
    box-shadow: var(--shadow-hover);
}

.generate-btn:active:not(:disabled) {
    transform: translateY(1px);
}

.generate-btn:disabled {
    background: var(--text-muted);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-content {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    transition: all var(--transition-fast);
}

.btn-loading {
    display: none;
    align-items: center;
    gap: var(--space-3);
}

.generate-btn:disabled .btn-content {
    display: none;
}

.generate-btn:disabled .btn-loading {
    display: flex;
}

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255,255,255,0.3);
    border-top: 2px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* ===== TIPS SECTION - DESKTOP ONLY ===== */
.tips-container {
    margin-top: var(--space-6);
    display: block;
}

@media (max-width: 768px) {
    .tips-container {
        display: none !important;
    }
}

.tips-card {
    background: var(--blue-50);
    border: 1px solid rgba(26, 115, 232, 0.12);
    border-radius: var(--radius-lg);
    padding: var(--space-4);
    transition: all var(--transition);
}

.tips-card:hover {
    box-shadow: 0 1px 3px rgba(60,64,67,0.3);
}

.tips-header {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    margin-bottom: var(--space-3);
    font-weight: 500;
    color: var(--text-primary);
    font-size: var(--font-sm);
}

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

.tips-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.tip-item {
    font-size: var(--font-xs);
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

kbd {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: var(--space-1) var(--space-2);
    font-family: 'Roboto Mono', monospace;
    font-size: 11px;
    box-shadow: 0 1px 2px rgba(60,64,67,0.3);
    color: var(--text-primary);
    display: inline-block;
    min-width: 20px;
    text-align: center;
}

/* ===== LOADING SECTION ===== */
.loading-container {
    display: none;
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    text-align: center;
    margin-bottom: var(--space-8);
}

.loading-container.show {
    display: block;
    animation: slideUp 0.3s ease;
}

.hidden {
    display: none;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.loading-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-6);
}

.loading-spinner {
    position: relative;
    width: 48px;
    height: 48px;
}

.spinner-ring {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 2px solid transparent;
    border-top: 2px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.spinner-ring:nth-child(1) { animation-delay: -0.3s; opacity: 1; }
.spinner-ring:nth-child(2) { animation-delay: -0.2s; opacity: 0.7; }
.spinner-ring:nth-child(3) { animation-delay: -0.1s; opacity: 0.4; }

.loading-text {
    color: var(--text-primary);
}

.loading-message {
    font-size: var(--font-base);
    margin-bottom: var(--space-4);
    font-weight: 400;
}

.progress-bar {
    width: 240px;
    height: 4px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary);
    border-radius: var(--radius-full);
    width: 0%;
    transition: width var(--transition);
    animation: progress 2.5s ease-in-out infinite;
}

@keyframes progress {
    0% { width: 0%; }
    50% { width: 70%; }
    100% { width: 100%; }
}

/* ===== RESULTS SECTION ===== */
.results-container {
    margin-top: var(--space-6);
}

.image-container {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow);
    animation: slideUp 0.3s ease;
    position: relative;
    margin-bottom: var(--space-6);
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-4);
}

.generated-image {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: all var(--transition);
    margin: 0;
}

.generated-image:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-hover);
}

.download-btn {
    background: var(--secondary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: var(--space-3) var(--space-5);
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: var(--font-sm);
    margin: 0;
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.download-btn:hover {
    background: var(--secondary-hover);
    box-shadow: var(--shadow);
}

.generation-info {
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    padding: var(--space-4);
    margin: 0;
    font-size: var(--font-xs);
    color: var(--text-secondary);
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-4);
    flex-wrap: wrap;
    border: 1px solid var(--border);
    box-shadow: 0 1px 2px rgba(60,64,67,0.3);
}

.generation-info p {
    margin: 0;
}

.generation-info strong {
    color: var(--text-primary);
    font-weight: 500;
}

/* ===== MESSAGES ===== */
.error-message {
    background: rgba(217, 48, 37, 0.1);
    color: var(--error);
    border: 1px solid rgba(217, 48, 37, 0.2);
    border-left: 4px solid var(--error);
    padding: var(--space-4);
    border-radius: var(--radius-md);
    margin: var(--space-4) 0;
    font-weight: 400;
    font-size: var(--font-sm);
    animation: slideDown 0.3s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border);
    padding: var(--space-8) var(--space-6);
    text-align: center;
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-text {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    font-weight: 400;
}

.heart {
    color: var(--error);
    animation: heartbeat 1.5s ease-in-out infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

/* ===== RESPONSIVE DESIGN ===== */

/* Tablet */
@media (max-width: 1024px) {
    .content-wrapper {
        max-width: 700px;
    }
    
    .hero-title {
        font-size: var(--font-3xl);
    }
}

/* Mobile */
@media (max-width: 768px) {
    :root {
        --space-6: 16px;
        --space-8: 24px;
        --space-12: 32px;
    }
    
    .header {
        padding: var(--space-4) 0;
    }
    
    .header-content {
        padding: 0 var(--space-4);
    }
    
    .logo {
        font-size: var(--font-lg);
    }
    
    .main-container {
        padding: var(--space-6) var(--space-4);
    }
    
    .hero-title {
        font-size: var(--font-2xl);
    }
    
    .hero-subtitle {
        font-size: var(--font-base);
    }
    
    .generator-card {
        padding: var(--space-6);
    }
    
    .generate-btn {
        font-size: var(--font-sm);
        padding: var(--space-4) var(--space-5);
    }
    
    .generation-info {
        flex-direction: column;
        gap: var(--space-2);
        padding: var(--space-3) var(--space-4);
        font-size: 11px;
    }
    
    .image-container {
        padding: var(--space-4);
        gap: var(--space-3);
    }
}

/* Mobile Small */
@media (max-width: 480px) {
    .generator-card {
        padding: var(--space-4);
    }
    
    .hero-title {
        font-size: var(--font-xl);
    }
    
    .prompt-input {
        padding: var(--space-3);
        min-height: 100px;
    }
    
    .size-select {
        padding: var(--space-3);
        height: 48px;
    }
    
    .generate-btn {
        padding: var(--space-3);
        min-height: 48px;
    }
    
    .loading-container {
        padding: var(--space-6);
    }
    
    .image-container {
        padding: var(--space-4);
    }
    
    .generation-info {
        flex-direction: column;
        text-align: center;
        gap: 4px;
        line-height: 1.3;
    }
}

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

@media (prefers-contrast: high) {
    :root {
        --border: currentColor;
    }
    
    .generator-card,
    .image-container {
        border-width: 2px;
    }
}

/* Print styles */
@media print {
    .header,
    .generator-card,
    .loading-container,
    .footer {
        display: none !important;
    }
    
    .results-container {
        margin-top: 0;
    }
    
    .generated-image {
        max-width: 100% !important;
        box-shadow: none !important;
    }
}