/* ============================================
   CSS Custom Properties
   ============================================ */
:root {
    --color-primary: #e74c3c;
    --color-primary-hover: #c0392b;
    --color-primary-light: rgba(231, 76, 60, 0.08);
    --color-primary-border: rgba(231, 76, 60, 0.3);
    --color-success: #27ae60;
    --color-success-light: rgba(39, 174, 96, 0.1);
    --color-danger: #e74c3c;
    --color-danger-light: rgba(231, 76, 60, 0.1);
    --color-text: #1a1a2e;
    --color-text-secondary: #555;
    --color-text-muted: #888;
    --color-bg: #f8f9fb;
    --color-white: #fff;
    --color-border: #e0e0e0;
    --color-border-light: #eee;
    --color-select-blue: #3498db;
    --color-select-blue-light: rgba(52, 152, 219, 0.1);
    --color-select-red: #e74c3c;
    --color-select-red-light: rgba(231, 76, 60, 0.08);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-card-hover: 0 8px 25px rgba(0, 0, 0, 0.15);
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --container-max: 960px;
}

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

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

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

/* ============================================
   Utilities
   ============================================ */
.hidden {
    display: none !important;
}

.fade-in {
    animation: fadeIn 0.3s ease forwards;
}

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

/* ============================================
   Header
   ============================================ */
.header {
    background: var(--color-white);
    border-bottom: 1px solid var(--color-border-light);
    padding: 14px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--color-text);
    text-decoration: none;
}

.privacy-badge {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    color: var(--color-success);
    font-weight: 500;
    background: var(--color-success-light);
    padding: 5px 12px;
    border-radius: 20px;
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
    flex: 1;
    padding: 40px 20px;
}

/* ============================================
   Step 1: Tool Selection
   ============================================ */
.hero {
    text-align: center;
    margin-bottom: 40px;
}

.hero h1 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--color-text);
}

.hero-subtitle {
    font-size: 1.05rem;
    color: var(--color-text-secondary);
    max-width: 560px;
    margin: 0 auto;
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    max-width: 700px;
    margin: 0 auto;
}

.tool-card {
    background: var(--color-white);
    border: 2px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    padding: 32px 24px;
    cursor: pointer;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
    text-align: center;
    font-family: inherit;
    font-size: inherit;
    color: inherit;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.tool-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-card-hover);
    border-color: var(--color-primary-border);
}

.tool-card:active {
    transform: translateY(-2px);
}

.tool-card-icon {
    color: var(--color-primary);
    margin-bottom: 4px;
}

.tool-card-title {
    font-size: 1.1rem;
    font-weight: 600;
}

.tool-card-desc {
    font-size: 0.88rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* ============================================
   Step 2: Upload
   ============================================ */
.step-header {
    margin-bottom: 30px;
}

.btn-back {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: none;
    border: none;
    color: var(--color-text-secondary);
    font-family: inherit;
    font-size: 0.9rem;
    cursor: pointer;
    padding: 6px 2px;
    margin-bottom: 16px;
    transition: color var(--transition-fast);
}

.btn-back:hover {
    color: var(--color-primary);
}

.step-header h2 {
    font-size: 1.6rem;
    font-weight: 700;
}

.upload-zone {
    border: 2.5px dashed var(--color-border);
    border-radius: var(--radius-lg);
    padding: 60px 40px;
    text-align: center;
    cursor: pointer;
    transition: border-color var(--transition-normal), background var(--transition-normal);
    background: var(--color-white);
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.upload-zone-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.upload-icon {
    color: var(--color-text-muted);
    margin-bottom: 8px;
}

.upload-text-main {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--color-text);
}

.upload-text-secondary {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
}

.upload-link {
    color: var(--color-primary);
    font-weight: 500;
    text-decoration: underline;
    text-decoration-color: var(--color-primary-border);
}

.upload-text-limit {
    font-size: 0.82rem;
    color: var(--color-text-muted);
    margin-top: 4px;
}

.privacy-message {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-top: 20px;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* ============================================
   Step 3: Preview + Controls
   ============================================ */
.file-info-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--color-white);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: 12px 18px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 10px;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
}

.file-name {
    font-weight: 600;
    color: var(--color-text);
}

.file-meta-sep {
    color: var(--color-border);
}

.control-panel {
    background: var(--color-white);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-bottom: 24px;
}

.control-label {
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 8px;
}

.control-hint {
    font-size: 0.88rem;
    color: var(--color-text-muted);
    margin-top: 4px;
}

.range-input-row {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 8px;
}

.input-field {
    flex: 1;
    padding: 10px 14px;
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 0.95rem;
    transition: border-color var(--transition-fast);
    outline: none;
}

.input-field:focus {
    border-color: var(--color-primary);
}

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

.range-hint {
    font-size: 0.82rem;
    color: var(--color-text-muted);
    white-space: nowrap;
}

.input-error {
    color: var(--color-danger);
    font-size: 0.84rem;
    margin-top: 6px;
}

.selection-count {
    font-size: 0.92rem;
    color: var(--color-text-secondary);
    margin-top: 4px;
    font-weight: 500;
}

/* Thumbnail grid */
.thumbnail-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.thumbnail-item {
    position: relative;
    border: 2.5px solid var(--color-border-light);
    border-radius: var(--radius-md);
    overflow: hidden;
    cursor: pointer;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast), opacity var(--transition-fast);
    background: var(--color-white);
}

.thumbnail-item:hover {
    box-shadow: var(--shadow-md);
}

.thumbnail-item canvas {
    display: block;
    width: 100%;
    height: auto;
}

.thumbnail-label {
    text-align: center;
    padding: 6px 0;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-bg);
}

/* Extract mode - selected */
.thumbnail-item.selected-extract {
    border-color: var(--color-select-blue);
    box-shadow: 0 0 0 3px var(--color-select-blue-light);
}

.thumbnail-item.selected-extract .thumbnail-check {
    display: flex;
}

.thumbnail-check {
    display: none;
    position: absolute;
    top: 8px;
    right: 8px;
    width: 26px;
    height: 26px;
    background: var(--color-select-blue);
    border-radius: 50%;
    align-items: center;
    justify-content: center;
    color: white;
}

/* Remove mode - selected */
.thumbnail-item.selected-remove {
    border-color: var(--color-select-red);
    box-shadow: 0 0 0 3px var(--color-select-red-light);
    opacity: 0.55;
}

.thumbnail-item.selected-remove .thumbnail-strikethrough {
    display: block;
}

.thumbnail-strikethrough {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.thumbnail-strikethrough::after {
    content: '';
    position: absolute;
    top: 50%;
    left: -5%;
    width: 110%;
    height: 3px;
    background: var(--color-select-red);
    transform: rotate(-20deg);
    border-radius: 2px;
}

/* Non-clickable thumbnails (range, split-all) */
.thumbnail-item.no-select {
    cursor: default;
}

.thumbnail-item.no-select:hover {
    box-shadow: none;
}

/* Action bar */
.action-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 8px;
}

/* ============================================
   Buttons
   ============================================ */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    padding: 12px 28px;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition-fast), transform var(--transition-fast);
}

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

.btn-primary:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.btn-lg {
    padding: 14px 36px;
    font-size: 1.05rem;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--color-white);
    color: var(--color-text-secondary);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 10px 20px;
    font-family: inherit;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: border-color var(--transition-fast), color var(--transition-fast);
}

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

.btn-sm {
    padding: 7px 14px;
    font-size: 0.82rem;
}

/* ============================================
   Step 4: Processing
   ============================================ */
.processing-overlay {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 340px;
    text-align: center;
    padding: 40px 20px;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--color-border-light);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-bottom: 24px;
}

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

.processing-status {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.progress-bar-container {
    width: 100%;
    max-width: 400px;
    height: 8px;
    background: var(--color-border-light);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 12px;
}

.progress-bar {
    height: 100%;
    background: var(--color-primary);
    border-radius: 4px;
    transition: width 0.3s ease;
}

.processing-detail {
    font-size: 0.88rem;
    color: var(--color-text-muted);
}

/* ============================================
   Step 5: Result
   ============================================ */
.result-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: 50px 40px;
    box-shadow: var(--shadow-md);
    max-width: 480px;
    margin: 0 auto;
}

.success-icon {
    margin-bottom: 20px;
    animation: scaleIn 0.4s ease forwards;
}

@keyframes scaleIn {
    from { transform: scale(0.5); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.result-title {
    font-size: 1.6rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.result-message {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    margin-bottom: 28px;
}

#btn-download {
    margin-bottom: 14px;
}

#btn-start-over {
    border: none;
    color: var(--color-primary);
    font-weight: 500;
}

#btn-start-over:hover {
    color: var(--color-primary-hover);
    border: none;
    background: var(--color-primary-light);
}

/* ============================================
   Legal Pages
   ============================================ */
.legal-content {
    max-width: 720px;
    margin: 0 auto;
    padding-bottom: 20px;
}

.legal-back {
    display: inline-block;
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 24px;
    transition: color var(--transition-fast);
}

.legal-back:hover {
    color: var(--color-primary);
}

.legal-content h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--color-text);
}

.legal-updated {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-bottom: 32px;
}

.legal-content h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-top: 32px;
    margin-bottom: 12px;
    color: var(--color-text);
}

.legal-content h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-top: 20px;
    margin-bottom: 8px;
    color: var(--color-text);
}

.legal-content p {
    margin-bottom: 14px;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.legal-content ul,
.legal-content ol {
    margin-bottom: 14px;
    padding-left: 24px;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.legal-content li {
    margin-bottom: 6px;
}

.legal-content a {
    color: var(--color-primary);
    text-decoration: underline;
    text-decoration-color: var(--color-primary-border);
    transition: color var(--transition-fast);
}

.legal-content a:hover {
    color: var(--color-primary-hover);
}

@media (max-width: 480px) {
    .legal-content h1 {
        font-size: 1.5rem;
    }

    .legal-content h2 {
        font-size: 1.1rem;
    }
}

/* ============================================
   Footer
   ============================================ */
.footer {
    padding: 40px 0 24px;
    font-size: 0.84rem;
    color: var(--color-text-muted);
    border-top: 1px solid var(--color-border-light);
    margin-top: auto;
    background: var(--color-white);
}

.footer-top {
    display: flex;
    gap: 48px;
    padding-bottom: 28px;
    border-bottom: 1px solid var(--color-border-light);
    margin-bottom: 20px;
}

.footer-brand {
    flex: 1;
    min-width: 200px;
}

.footer-brand .logo {
    margin-bottom: 10px;
    font-size: 1rem;
}

.footer-tagline {
    font-size: 0.84rem;
    line-height: 1.6;
    color: var(--color-text-muted);
    max-width: 280px;
}

.footer-links {
    display: flex;
    gap: 40px;
    flex-wrap: wrap;
}

.footer-col h4 {
    font-size: 0.84rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.footer-col ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.footer-col li {
    font-size: 0.84rem;
    color: var(--color-text-muted);
}

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

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

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 16px;
}

.footer-made {
    color: var(--color-text-muted);
}

.heart {
    color: var(--color-primary);
    font-size: 1em;
}

.footer-disclaimer {
    border-top: 1px solid var(--color-border-light);
    padding-top: 16px;
    font-size: 0.76rem;
    line-height: 1.7;
    color: var(--color-text-muted);
    max-width: 720px;
}

@media (max-width: 768px) {
    .footer-top {
        flex-direction: column;
        gap: 28px;
    }

    .footer-links {
        gap: 24px;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 4px;
        text-align: center;
    }
}

/* ============================================
   Error Toast
   ============================================ */
.error-toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: #2d2d2d;
    color: white;
    padding: 14px 22px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s ease, transform 0.3s ease;
    max-width: 90%;
}

.error-toast.visible {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.error-toast svg {
    flex-shrink: 0;
    color: var(--color-danger);
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 1.7rem;
    }

    .hero-subtitle {
        font-size: 0.95rem;
    }

    .tool-grid {
        grid-template-columns: 1fr;
        gap: 14px;
    }

    .tool-card {
        padding: 24px 20px;
        flex-direction: row;
        text-align: left;
        gap: 16px;
    }

    .tool-card-icon {
        margin-bottom: 0;
    }

    .tool-card-title {
        font-size: 1rem;
    }

    .tool-card-desc {
        font-size: 0.84rem;
    }

    .upload-zone {
        padding: 40px 20px;
    }

    .thumbnail-grid {
        grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
        gap: 12px;
    }

    .file-info-bar {
        flex-direction: column;
        align-items: flex-start;
    }

    .action-bar {
        flex-direction: column-reverse;
        gap: 12px;
    }

    .action-bar .btn-primary {
        width: 100%;
        justify-content: center;
    }

    .action-bar .btn-secondary {
        width: 100%;
        justify-content: center;
    }

    .result-card {
        padding: 36px 24px;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.4rem;
    }

    .main-content {
        padding: 24px 12px;
    }

    .thumbnail-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .privacy-badge {
        font-size: 0.72rem;
        padding: 4px 8px;
    }
}

/* ============================================
   Homepage Action Chooser
   ============================================ */
.homepage-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 16px;
}

.btn-hp-action {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 18px;
    background: var(--color-white);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: border-color var(--transition-fast), background var(--transition-fast), opacity var(--transition-fast);
    color: var(--color-text);
}

.btn-hp-action:hover:not(:disabled) {
    border-color: var(--color-primary-border);
    background: var(--color-primary-light);
}

.btn-hp-action:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

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

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

.btn-hp-action svg {
    flex-shrink: 0;
}

.hp-range-panel {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--color-border-light);
}

@media (max-width: 768px) {
    .homepage-actions {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   Tool Showcase
   ============================================ */
.tool-showcase {
    padding: 48px 0;
    border-top: 1px solid var(--color-border-light);
    margin-top: 40px;
}

.tool-showcase-title {
    text-align: center;
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--color-text);
}

.tool-showcase-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    max-width: 800px;
    margin: 0 auto;
}

.tool-showcase-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 24px 16px;
    background: var(--color-white);
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-md);
    text-decoration: none;
    color: inherit;
    text-align: center;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.tool-showcase-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary-border);
}

.tool-showcase-card .tool-card-icon {
    color: var(--color-primary);
    margin-bottom: 4px;
}

.tool-showcase-card h3 {
    font-size: 0.95rem;
    font-weight: 600;
}

.tool-showcase-card p {
    font-size: 0.82rem;
    color: var(--color-text-secondary);
    line-height: 1.4;
}

@media (max-width: 768px) {
    .tool-showcase-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .tool-showcase-grid {
        grid-template-columns: 1fr;
    }

    .tool-showcase {
        padding: 32px 0;
        margin-top: 24px;
    }
}