/* Global reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    color-scheme: light;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #111111;
    background: #F8F8F7;
    --bg: #F8F8F7;
    --surface: #ffffff;
    --surface-soft: #f1f3f5;
    --border: #e9ecef;
    --text: #111111;
    --muted: #6c757d;
    --accent: #1d4ed8;
    --accent-soft: rgba(29, 78, 216, 0.14);
    --shadow: 0 18px 40px rgba(17, 17, 17, 0.08);
    --shadow-soft: 0 8px 28px rgba(17, 17, 17, 0.06);
    --radius: 14px;
}

html {
    scroll-behavior: smooth;
}

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

body::before {
    content: '';
    position: fixed;
    inset: 0;
    background: radial-gradient(circle at top left, rgba(29, 78, 216, 0.12), transparent 32%),
                radial-gradient(circle at bottom right, rgba(29, 78, 216, 0.09), transparent 28%);
    pointer-events: none;
    z-index: -1;
}

img, picture, svg {
    display: block;
    max-width: 100%;
}

button, input, textarea, select {
    font: inherit;
}

a {
    color: inherit;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.container {
    width: min(1160px, calc(100% - 48px));
    margin: 0 auto;
    padding: 40px 0 60px;
}

.site-header,
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(233, 236, 239, 0.9);
}

.nav-container {
    max-width: 1160px;
    margin: 0 auto;
    padding: 18px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    background: rgba(29, 78, 216, 0.12);
    color: var(--accent);
    display: grid;
    place-items: center;
    font-weight: 800;
    letter-spacing: 0.02em;
}

.logo-text {
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text);
}

.nav-menu {
    display: flex;
    gap: 12px;
    list-style: none;
    align-items: center;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    padding: 12px 16px;
    border-radius: 12px;
    color: var(--muted);
    font-weight: 600;
    font-size: 0.95rem;
    transition: background-color 0.25s ease, color 0.25s ease, transform 0.25s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent);
    background: var(--accent-soft);
}

.mobile-menu-btn {
    display: none;
    border: 1px solid rgba(17, 17, 17, 0.08);
    border-radius: 12px;
    background: var(--surface);
    color: var(--text);
    padding: 12px 14px;
    cursor: pointer;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.mobile-menu-btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-soft);
}

.hero {
    margin-top: 20px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 48px 46px;
    box-shadow: var(--shadow-soft);
}

.hero h1 {
    font-size: clamp(2.4rem, 5vw, 1.5rem);
    line-height: 1.05;
    margin-bottom: 20px;
    letter-spacing: -0.04em;
}

.hero p {
    font-size: 1.05rem;
    max-width: 760px;
    color: var(--muted);
    margin-bottom: 26px;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(29, 78, 216, 0.08);
    color: var(--accent);
    border-radius: 999px;
    padding: 10px 16px;
    font-weight: 700;
    font-size: 0.9rem;
}

.tool-section {
    margin-top: 36px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 24px;
    box-shadow: var(--shadow-soft);
    padding: 36px;
    animation: fadeIn 0.45s ease forwards;
}

.section-header {
    margin-bottom: 28px;
}

.section-title {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 12px;
    letter-spacing: -0.03em;
    color: var(--text);
}

.section-desc {
    color: var(--muted);
    font-size: 1rem;
    max-width: 720px;
}

.upload-zone {
    position: relative;
    border: 2px dashed var(--border);
    border-radius: 22px;
    padding: 46px 38px;
    text-align: center;
    background: var(--surface-soft);
    transition: border-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
    cursor: pointer;
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: rgba(29, 78, 216, 0.6);
    transform: translateY(-1px);
    box-shadow: 0 16px 32px rgba(17, 17, 17, 0.06);
}

.upload-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 22px;
    border-radius: 18px;
    background: rgba(29, 78, 216, 0.08);
    display: grid;
    place-items: center;
    font-size: 1.8rem;
}

.upload-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text);
}

.upload-text {
    color: var(--muted);
    margin-bottom: 18px;
    font-size: 1rem;
}

.upload-limits {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 18px;
}

.limit-tag {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--muted);
    border-radius: 999px;
    padding: 10px 16px;
    font-size: 0.9rem;
    font-weight: 600;
}

.file-input {
    display: none;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 14px 28px;
    border-radius: 12px;
    border: none;
    font-weight: 700;
    font-size: 0.95rem;
    cursor: pointer;
    transition: transform 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
    background: var(--accent);
    color: #ffffff;
    box-shadow: 0 14px 30px rgba(29, 78, 216, 0.18);
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 18px 36px rgba(29, 78, 216, 0.16);
}

.btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
}

.btn-zip,
.btn-success,
.btn-danger {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    box-shadow: none;
}

.btn-zip:hover,
.btn-success:hover,
.btn-danger:hover {
    background: var(--surface);
    border-color: rgba(29, 78, 216, 0.4);
    color: var(--accent);
}

.btn-success {
    color: var(--accent);
}

.btn-danger {
    color: var(--muted);
}

.controls {
    background: var(--surface-soft);
    padding: 28px;
    border-radius: 20px;
    border: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap;
    margin: 32px 0;
}

.control-label {
    font-weight: 700;
    color: var(--text);
}

.slider-container {
    flex: 1;
    min-width: 180px;
}

.slider {
    width: 100%;
    height: 10px;
    border-radius: 999px;
    background: linear-gradient(90deg, var(--accent) 0%, rgba(29, 78, 216, 0.28) 100%);
    outline: none;
    -webkit-appearance: none;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--surface);
    border: 4px solid var(--accent);
    cursor: pointer;
    box-shadow: 0 8px 20px rgba(17, 17, 17, 0.12);
}

.quality-value {
    min-width: 70px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent);
    font-weight: 700;
    padding: 12px 18px;
}

.images-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 32px;
}

.image-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 24px;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.image-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-soft);
    border-color: rgba(29, 78, 216, 0.2);
}

.image-preview {
    display: flex;
    gap: 16px;
    margin-bottom: 20px;
}

.preview-box {
    flex: 1;
    text-align: center;
}

.preview-label {
    font-size: 0.76rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 10px;
}

.preview-image {
    width: 100%;
    height: 170px;
    object-fit: contain;
    border-radius: 16px;
    background: var(--bg);
    border: 1px solid var(--border);
}

.image-info {
    margin-bottom: 18px;
}

.image-name {
    font-weight: 700;
    color: var(--text);
    margin-bottom: 10px;
    word-break: break-word;
}

.size-comparison {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.size-box,
.savings {
    padding: 10px 14px;
    border-radius: 999px;
    font-size: 0.85rem;
    font-weight: 700;
}

.size-original {
    background: #f8f9fa;
    color: var(--muted);
}

.size-compressed {
    background: #e7f1ff;
    color: var(--accent);
}

.savings {
    background: var(--accent-soft);
    color: var(--accent);
}

.action-buttons {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.btn-small {
    padding: 12px 18px;
    font-size: 0.9rem;
}

.action-bar {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 28px;
    padding: 24px;
    border-radius: 20px;
    background: var(--surface-soft);
    border: 1px solid var(--border);
}

.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 18px;
    margin-top: 30px;
}

.stat-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 24px;
    text-align: center;
}

.stat-value {
    font-size: 2.1rem;
    font-weight: 800;
    color: var(--accent);
    margin-bottom: 10px;
}

.stat-label {
    color: var(--muted);
    font-weight: 600;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-top: 32px;
}

.feature-card {
    background: var(--surface);
    border-radius: 20px;
    border: 1px solid var(--border);
    padding: 30px 26px;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-soft);
}

.feature-icon {
    width: 60px;
    height: 60px;
    display: grid;
    place-items: center;
    border-radius: 16px;
    background: rgba(29, 78, 216, 0.08);
    color: var(--accent);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.feature-title {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 12px;
}

.feature-text {
    color: var(--muted);
    line-height: 1.7;
}

.footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 32px 24px;
    color: var(--muted);
    text-align: center;
}

.footer-inner {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer p {
    font-size: 0.95rem;
}

.footer-note {
    margin-top: 4px;
    opacity: 0.8;
}

.footer a {
    color: var(--accent);
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

.format-selector {
    background: var(--surface-soft);
    padding: 28px;
    border-radius: 22px;
    border: 1px solid var(--border);
    margin: 28px 0;
}

.format-selector-title {
    color: var(--text);
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 20px;
}

.format-buttons,
.quick-convert {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    align-items: center;
}

.format-btn,
.quick-btn {
    padding: 12px 22px;
    border-radius: 12px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    transition: background-color 0.25s ease, border-color 0.25s ease, color 0.25s ease;
}

.format-btn:hover,
.quick-btn:hover {
    border-color: rgba(29, 78, 216, 0.4);
    color: var(--accent);
}

.format-btn.active {
    background: var(--accent);
    color: #ffffff;
    border-color: var(--accent);
}

.format-arrow {
    color: var(--muted);
    font-size: 1.25rem;
    font-weight: 700;
}

.format-source {
    color: var(--accent);
    font-weight: 700;
    font-size: 1rem;
}

.divider {
    position: relative;
    text-align: center;
    margin: 34px 0;
    color: var(--muted);
    font-size: 0.85rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
}

.divider::before,
.divider::after {
    content: '';
    position: absolute;
    top: 50%;
    width: 40%;
    height: 1px;
    background: var(--border);
}

.divider::before { left: 0; }
.divider::after { right: 0; }

.html-textarea {
    width: 100%;
    min-height: 220px;
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 18px;
    font-family: 'Courier New', monospace;
    background: var(--surface);
    color: var(--text);
    font-size: 0.95rem;
    resize: vertical;
    transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.html-textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 6px rgba(29, 78, 216, 0.08);
}

.html-textarea::placeholder {
    color: rgba(17, 17, 17, 0.35);
}

.alt-checker-input {
    background: var(--surface-soft);
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 32px;
    margin-bottom: 30px;
}

.alt-checker-input h3 {
    margin-bottom: 16px;
    color: var(--text);
    font-size: 1.2rem;
}

.alt-checker-input .input-hint {
    color: var(--muted);
    font-size: 0.96rem;
    line-height: 1.8;
}

.alt-checker-input .input-group {
    display: flex;
    gap: 12px;
    align-items: center;
    flex-wrap: wrap;
}

.url-input {
    flex: 1;
    min-width: 220px;
    padding: 16px 18px;
    border-radius: 14px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    font-size: 0.98rem;
}

.url-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 6px rgba(29, 78, 216, 0.08);
}

.loading-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 14px;
    padding: 30px;
    background: var(--surface-soft);
    border: 1px solid var(--border);
    border-radius: 22px;
    margin: 20px 0;
}

.loading {
    display: inline-block;
    width: 22px;
    height: 22px;
    border: 3px solid rgba(29, 78, 216, 0.2);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.9s linear infinite;
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 900px) {
    .nav-container {
        flex-wrap: wrap;
        padding: 18px 20px;
    }

    .nav-menu {
        order: 3;
        width: 100%;
        display: none;
        flex-direction: column;
        gap: 10px;
        background: var(--surface);
        border: 1px solid var(--border);
        border-radius: 18px;
        padding: 20px;
        box-shadow: var(--shadow-soft);
        margin-top: 14px;
    }

    .nav-menu.show {
        display: flex;
    }

    .nav-link {
        width: 100%;
        text-align: center;
    }

    .mobile-menu-btn {
        display: inline-flex;
    }
}

@media (max-width: 768px) {
    .container {
        width: min(100%, calc(100% - 32px));
        padding: 28px 0 48px;
    }

    .hero {
        padding: 32px 26px;
    }

    .tool-section {
        padding: 28px 22px;
    }

    .upload-zone {
        padding: 32px 24px;
    }

    .upload-title {
        font-size: 1.15rem;
    }

    .images-grid {
        grid-template-columns: 1fr;
    }

    .controls,
    .action-bar,
    .format-buttons,
    .quick-convert {
        flex-direction: column;
        align-items: stretch;
    }

    .btn,
    .btn-zip,
    .btn-success,
    .btn-danger,
    .format-btn,
    .quick-btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .nav-container {
        padding: 16px 18px;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    .hero p,
    .section-desc,
    .upload-text,
    .feature-text {
        font-size: 0.98rem;
    }

    .upload-icon {
        width: 64px;
        height: 64px;
        font-size: 1.5rem;
    }
}