/* ==========================================
   ConvertImage Free — Flat UI Stylesheet
   ========================================== */

:root {
    --blue-50: #eff6ff;
    --blue-100: #dbeafe;
    --blue-200: #bfdbfe;
    --blue-300: #93c5fd;
    --blue-400: #60a5fa;
    --blue-500: #3b82f6;
    --blue-600: #2563eb;
    --blue-700: #1d4ed8;
    --blue-800: #1e40af;
    --blue-900: #1e3a8a;

    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;

    --green-500: #22c55e;
    --green-600: #16a34a;
    --purple-500: #a855f7;
    --orange-500: #f97316;
    --pink-500: #ec4899;
    --teal-500: #14b8a6;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-2xl: 24px;
    --radius-full: 9999px;

    --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 30px rgba(0,0,0,0.08);
    --shadow-xl: 0 16px 48px rgba(0,0,0,0.1);

    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font);
    background: var(--gray-50);
    color: var(--gray-800);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; height: auto; display: block; }
a { text-decoration: none; color: inherit; }

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ==========================================
   Gradient Text
   ========================================== */
.gradient-text {
    background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ==========================================
   Header
   ========================================== */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--gray-200);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.15rem;
}

.logo-img {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-md);
    object-fit: contain;
}

.logo-text {
    color: var(--gray-900);
}

.logo-badge {
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: 2px 8px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
    color: #fff;
}

.header-nav {
    display: flex;
    gap: 28px;
}

.header-nav a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-500);
    transition: color var(--transition);
}

.header-nav a:hover {
    color: var(--blue-600);
}

/* ==========================================
   Hero
   ========================================== */
.hero {
    text-align: center;
    padding: 72px 0 48px;
}

.hero-badge {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--blue-600);
    background: var(--blue-50);
    border: 1px solid var(--blue-200);
    padding: 6px 20px;
    border-radius: var(--radius-full);
    margin-bottom: 20px;
    letter-spacing: 0.02em;
}

.hero h1 {
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 800;
    line-height: 1.15;
    color: var(--gray-900);
    margin-bottom: 16px;
}

.hero-subtitle {
    max-width: 620px;
    margin: 0 auto 28px;
    font-size: 1.1rem;
    color: var(--gray-500);
    line-height: 1.7;
}

.hero-formats {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
}

.format-pill {
    font-size: 0.78rem;
    font-weight: 600;
    padding: 5px 14px;
    border-radius: var(--radius-full);
    background: #fff;
    border: 1px solid var(--gray-200);
    color: var(--gray-600);
    transition: all var(--transition);
}

.format-pill:hover {
    border-color: var(--blue-300);
    background: var(--blue-50);
    color: var(--blue-600);
}

.format-pill.accent {
    background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
    color: #fff;
    border-color: transparent;
}

/* ==========================================
   Converter Section
   ========================================== */
.converter-section {
    padding: 0 0 80px;
}

.converter-card {
    background: #fff;
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-lg);
    padding: 32px;
    border: 1px solid var(--gray-100);
}

/* Upload Area */
.upload-area {
    border: 2px dashed var(--blue-300);
    border-radius: var(--radius-xl);
    padding: 56px 32px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition);
    background: var(--blue-50);
    position: relative;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--blue-500);
    background: var(--blue-100);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(59, 130, 246, 0.12);
}

.upload-area.dragover {
    border-style: solid;
}

.upload-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 16px;
    background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    box-shadow: 0 8px 24px rgba(59, 130, 246, 0.3);
}

.upload-text {
    font-size: 1.05rem;
    color: var(--gray-600);
    margin-bottom: 6px;
}

.upload-text strong {
    color: var(--blue-600);
}

.upload-hint {
    font-size: 0.85rem;
    color: var(--gray-400);
}

/* Controls */
.controls {
    margin-top: 24px;
    animation: fadeIn 0.3s ease;
}

.controls-row {
    display: flex;
    gap: 24px;
    align-items: flex-end;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.control-group {
    flex: 1;
    min-width: 200px;
}

.control-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gray-600);
    margin-bottom: 6px;
}

select {
    width: 100%;
    padding: 10px 14px;
    font-size: 0.95rem;
    font-family: var(--font);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    background: #fff;
    color: var(--gray-800);
    cursor: pointer;
    transition: border-color var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

select:focus {
    outline: none;
    border-color: var(--blue-500);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

input[type="range"] {
    width: 100%;
    height: 6px;
    -webkit-appearance: none;
    appearance: none;
    border-radius: var(--radius-full);
    background: var(--gray-200);
    outline: none;
    margin-top: 4px;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--blue-500);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
    transition: transform var(--transition);
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--blue-500);
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.controls-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    font-size: 0.9rem;
    font-weight: 600;
    font-family: var(--font);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
    color: #fff;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25);
}

.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.35);
    transform: translateY(-1px);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--gray-800);
    color: #fff;
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    background: var(--gray-700);
    transform: translateY(-1px);
}

.btn-outline {
    background: #fff;
    color: var(--blue-600);
    border: 1px solid var(--blue-200);
}

.btn-outline:hover {
    background: var(--blue-50);
    border-color: var(--blue-400);
}

.btn-ghost {
    background: transparent;
    color: var(--gray-500);
}

.btn-ghost:hover {
    background: var(--gray-100);
    color: var(--gray-700);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

/* Progress Bar */
.progress-bar-container {
    margin-top: 20px;
    background: var(--gray-100);
    border-radius: var(--radius-full);
    height: 8px;
    position: relative;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--blue-500), var(--blue-600));
    border-radius: var(--radius-full);
    width: 0%;
    transition: width 0.3s ease;
}

.progress-text {
    position: absolute;
    right: 0;
    top: -24px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--blue-600);
}

/* Preview Grid */
.preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
    margin-top: 24px;
}

.preview-item {
    background: var(--gray-50);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition);
    animation: fadeInUp 0.3s ease;
}

.preview-item:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--blue-200);
}

.preview-thumb {
    width: 100%;
    height: 140px;
    object-fit: cover;
    background: var(--gray-100);
    display: block;
}

.preview-info {
    padding: 12px;
}

.preview-name {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--gray-700);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preview-meta {
    font-size: 0.75rem;
    color: var(--gray-400);
    margin-top: 2px;
}

.preview-actions {
    display: flex;
    gap: 6px;
    margin-top: 8px;
}

.preview-actions .btn {
    padding: 6px 12px;
    font-size: 0.78rem;
    flex: 1;
    justify-content: center;
}

.preview-converted {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 0.75rem;
    color: var(--green-600);
    font-weight: 600;
    margin-top: 6px;
}

.preview-converted svg {
    flex-shrink: 0;
}

/* ==========================================
   Features Section
   ========================================== */
.features-section {
    padding: 80px 0;
}

.features-illustration {
    max-width: 680px;
    margin: 0 auto 48px;
    text-align: center;
}

.features-illustration svg {
    width: 100%;
    height: auto;
    max-height: 200px;
}

.features-section h2,
.howto-section h2,
.conversions-section h2,
.faq-section h2 {
    text-align: center;
    font-size: clamp(1.8rem, 3.5vw, 2.4rem);
    font-weight: 800;
    color: var(--gray-900);
    margin-bottom: 8px;
}

.section-subtitle {
    text-align: center;
    color: var(--gray-500);
    font-size: 1.05rem;
    margin-bottom: 48px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.feature-card {
    background: var(--gray-50);
    border-radius: var(--radius-xl);
    padding: 32px 28px;
    border: 1px solid var(--gray-200);
    transition: all var(--transition);
}

.feature-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    border-color: var(--gray-300);
}

.feature-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 10px;
}

.feature-card p {
    font-size: 0.9rem;
    color: var(--gray-500);
    line-height: 1.7;
}

/* ==========================================
   How It Works
   ========================================== */
.howto-section {
    padding: 80px 0;
    background: #fff;
}

.steps-grid {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
}

.step-card {
    background: var(--gray-50);
    border-radius: var(--radius-xl);
    padding: 32px 24px;
    text-align: center;
    flex: 1;
    max-width: 280px;
    border: 1px solid var(--gray-100);
    transition: all var(--transition);
}

.step-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-3px);
}

.step-number {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
    color: #fff;
    font-size: 1.2rem;
    font-weight: 800;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25);
}

.step-card h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--gray-900);
}

.step-card p {
    font-size: 0.85rem;
    color: var(--gray-500);
    line-height: 1.6;
}

.step-arrow {
    color: var(--gray-300);
    flex-shrink: 0;
}

/* ==========================================
   Supported Conversions
   ========================================== */
.conversions-section {
    padding: 80px 0;
}

.conversions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 10px;
}

.conversion-item {
    text-align: center;
    padding: 12px 8px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gray-600);
    background: #fff;
    border-radius: var(--radius-md);
    border: 1px solid var(--gray-100);
    transition: all var(--transition);
}

.conversion-item:hover {
    border-color: var(--blue-300);
    background: var(--blue-50);
    color: var(--blue-600);
    transform: translateY(-2px);
}

/* ==========================================
   FAQ Section
   ========================================== */
.faq-section {
    padding: 80px 0;
    background: #fff;
}

.faq-list {
    max-width: 720px;
    margin: 0 auto;
}

.faq-item {
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    margin-bottom: 12px;
    overflow: hidden;
    transition: all var(--transition);
}

.faq-item:hover {
    border-color: var(--blue-200);
}

.faq-item[open] {
    border-color: var(--blue-300);
    box-shadow: 0 2px 12px rgba(59, 130, 246, 0.08);
}

.faq-item summary {
    padding: 18px 24px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--gray-800);
    cursor: pointer;
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: background var(--transition);
}

.faq-item summary::-webkit-details-marker { display: none; }

.faq-item summary::after {
    content: '+';
    font-size: 1.3rem;
    font-weight: 400;
    color: var(--gray-400);
    transition: transform var(--transition);
    flex-shrink: 0;
    margin-left: 16px;
}

.faq-item[open] summary::after {
    content: '−';
    color: var(--blue-500);
}

.faq-item summary:hover {
    background: var(--gray-50);
}

.faq-item p {
    padding: 0 24px 18px;
    font-size: 0.9rem;
    color: var(--gray-500);
    line-height: 1.7;
}

/* ==========================================
   Footer
   ========================================== */
.footer {
    padding: 40px 0;
    border-top: 1px solid var(--gray-200);
    text-align: center;
}

.footer-inner p {
    font-size: 0.85rem;
    color: var(--gray-400);
}

.footer-sub {
    margin-top: 4px;
    font-size: 0.8rem !important;
}

/* ==========================================
   Animations
   ========================================== */
@keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

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

/* ==========================================
   Responsive
   ========================================== */
@media (max-width: 900px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .steps-grid {
        flex-direction: column;
    }
    .step-arrow {
        transform: rotate(90deg);
    }
    .step-card {
        max-width: 100%;
    }
}

@media (max-width: 640px) {
    .header-nav {
        display: none;
    }
    .hero {
        padding: 48px 0 32px;
    }
    .hero h1 {
        font-size: 2rem;
    }
    .converter-card {
        padding: 20px;
        border-radius: var(--radius-lg);
    }
    .upload-area {
        padding: 40px 20px;
    }
    .features-grid {
        grid-template-columns: 1fr;
    }
    .controls-row {
        flex-direction: column;
        gap: 16px;
    }
    .controls-actions {
        flex-direction: column;
    }
    .controls-actions .btn {
        justify-content: center;
    }
    .preview-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
    .conversions-grid {
        grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
    }
}