/* ===== CSS Variables ===== */
:root {
    /* Ink Wash & Day Mode Palette */
    --bg-primary: #F7F5F0;
    /* Rice Paper White */
    --bg-secondary: #ECEAE4;
    --bg-card: rgba(255, 255, 255, 0.8);
    --bg-card-hover: #FFFFFF;
    --bg-glass: rgba(255, 255, 255, 0.6);

    --text-primary: #2B2B2B;
    /* Deep Charcoal (Ink) */
    --text-secondary: #555555;
    /* Light Ink */
    --text-muted: #8F8F8F;

    /* Pale Red / Cinnabar Accent */
    --accent-primary: #E65A5A;
    /* Pale Red */
    --accent-secondary: #D44E4E;
    --accent-glow: rgba(230, 90, 90, 0.15);

    --success: #679476;
    /* Muted Green */
    --warning: #E0A64E;
    /* Amber */
    --error: #D9534F;
    /* Muted Red */

    --border-color: rgba(43, 43, 43, 0.08);
    --border-radius: 16px;
    --border-radius-sm: 8px;

    --shadow-sm: 0 2px 12px rgba(43, 43, 43, 0.03);
    --shadow-md: 0 8px 30px rgba(43, 43, 43, 0.06);
    --shadow-glow: 0 0 40px var(--accent-glow);

    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;

    /* Fonts: Clean modern sans-serif for both Chinese and English */
    --font-sans: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-heading: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

/* ===== 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);
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
    /* Subtle paper texture effect */
    background-image: radial-gradient(#E8E6E1 1px, transparent 0);
    background-size: 40px 40px;
}

/* Ink Wash Gradients - Subtle background blobs */
body::before {
    content: '';
    position: fixed;
    top: -20%;
    left: -10%;
    width: 60%;
    height: 60%;
    background: radial-gradient(circle, rgba(230, 90, 90, 0.03), transparent 70%);
    pointer-events: none;
    z-index: -1;
    filter: blur(60px);
}

body::after {
    content: '';
    position: fixed;
    bottom: -20%;
    right: -10%;
    width: 60%;
    height: 60%;
    background: radial-gradient(circle, rgba(200, 200, 200, 0.05), transparent 70%);
    pointer-events: none;
    z-index: -1;
    filter: blur(60px);
}

/* ===== App Container ===== */
.app-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 3rem 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Header ===== */
.header {
    width: 100%;
    margin-bottom: 2rem;
    padding: 1rem 0;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
    cursor: default;
    /* Give it a feel of interaction potential */
}

.logo:hover .logo-icon {
    transform: rotate(15deg) scale(1.1);
}

.logo-icon {
    width: 40px;
    height: 40px;
    color: var(--accent-primary);
    /* Ink style filter */
    filter: drop-shadow(2px 4px 6px rgba(230, 90, 90, 0.2));
    transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* Generic Link Styles for any inline links */
a:not([class]) {
    color: var(--accent-primary);
    text-decoration: none;
    position: relative;
    font-weight: 500;
}

a:not([class])::after {
    content: '';
    position: absolute;
    width: 100%;
    transform: scaleX(0);
    height: 1.5px;
    bottom: -1px;
    left: 0;
    background-color: currentColor;
    transform-origin: bottom right;
    transition: transform 0.25s ease-out;
}

a:not([class]):hover::after {
    transform: scaleX(1);
    transform-origin: bottom left;
}

.logo h1 {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.browser-warning {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(224, 166, 78, 0.1);
    border: 1px solid rgba(224, 166, 78, 0.2);
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    color: var(--warning);
}

/* Header Actions */
.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.lang-switcher {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 100px;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.lang-switcher:hover {
    background: #FFFFFF;
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    box-shadow: var(--shadow-sm);
}

.lang-switcher svg {
    flex-shrink: 0;
}

/* ===== Mode Toggle ===== */
.mode-toggle-container {
    display: flex;
    justify-content: center;
    margin-bottom: 3rem;
}

.mode-toggle {
    position: relative;
    display: flex;
    background: #EAE8E3;
    /* Slightly darker paper for toggle background */
    border-radius: 100px;
    /* Pill shape */
    padding: 4px;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.03);
}

.mode-btn {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 2rem;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: color var(--transition-normal);
    border-radius: 100px;
}

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

.mode-btn.active {
    color: #FFFFFF;
    /* White text on red background */
}

.mode-icon {
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.mode-slider {
    position: absolute;
    top: 4px;
    left: 4px;
    width: calc(50% - 4px);
    height: calc(100% - 8px);
    background: var(--accent-primary);
    border-radius: 100px;
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 4px 12px var(--accent-glow);
}

.mode-slider.remove {
    transform: translateX(100%);
}

/* ===== Main Content ===== */
.main-content {
    flex: 1;
    width: 100%;
}

/* ===== Upload Section ===== */
.upload-section {
    margin-bottom: 3rem;
    animation: fadeIn 0.6s ease-out;
}

.upload-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 5rem 2rem;
    background: #FFFFFF;
    border: 2px dashed #DCDAD5;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--accent-primary);
    box-shadow: var(--shadow-sm);
    background: #FFFAFA;
    /* Very light pink/white */
}

.upload-area.dragover {
    transform: scale(1.005);
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    transition: color var(--transition-normal);
}

.upload-area:hover .upload-icon {
    color: var(--accent-primary);
}

.upload-icon svg {
    width: 100%;
    height: 100%;
}

.upload-text {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.upload-hint {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* ===== Preview Section ===== */
.preview-section {
    animation: fadeIn var(--transition-slow) ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.preview-grid {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 2rem;
    align-items: start;
    margin-bottom: 3rem;
}

.preview-card {
    background: #FFFFFF;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: box-shadow var(--transition-normal);
}

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

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    background: #FBFAF8;
}

.preview-label {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 1rem;
    color: var(--text-primary);
}

.image-info {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: 'SF Mono', 'Menlo', monospace;
    background: rgba(0, 0, 0, 0.03);
    padding: 2px 6px;
    border-radius: 4px;
}

.preview-image-container {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 300px;
    padding: 1.5rem;
    background:
        linear-gradient(45deg, #F5F5F5 25%, transparent 25%),
        linear-gradient(-45deg, #F5F5F5 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #F5F5F5 75%),
        linear-gradient(-45deg, transparent 75%, #F5F5F5 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

.preview-image-container img,
.preview-image-container canvas {
    max-width: 100%;
    max-height: 500px;
    object-fit: contain;
    border-radius: var(--border-radius-sm);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.processing-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(2px);
    color: var(--text-primary);
    font-size: 0.9rem;
    font-weight: 500;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid rgba(230, 90, 90, 0.2);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.preview-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 150px;
}

.preview-arrow svg {
    width: 40px;
    height: 40px;
    color: var(--text-muted);
    opacity: 0.5;
}

/* ===== Actions ===== */
.actions {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.875rem 2rem;
    border: none;
    border-radius: 100px;
    /* Pill shape buttons */
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    line-height: 1;
    vertical-align: middle;
}

.btn-icon svg {
    display: block;
}

.btn-primary {
    background: var(--accent-primary);
    color: #FFFFFF;
    box-shadow: 0 4px 15px rgba(230, 90, 90, 0.3);
}

.btn-primary:hover {
    background: var(--accent-secondary);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(230, 90, 90, 0.4);
}

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

.btn-secondary {
    background: #FFFFFF;
    color: var(--text-primary);
    border: 1px solid #E0E0E0;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.02);
}

.btn-secondary:hover {
    background: #FAFAFA;
    border-color: #D0D0D0;
    transform: translateY(-1px);
}

/* ===== Footer ===== */
.footer {
    padding: 4rem 0 2rem;
    color: var(--text-muted);
    font-size: 0.875rem;
    border-top: 1px solid var(--border-color);
    margin-top: 4rem;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
    margin-bottom: 2.5rem;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
    text-align: center;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.link-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    background: #FFFFFF;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-fast);
    font-size: 0.9rem;
    width: fit-content;
}

.link-item:hover {
    background: var(--bg-primary);
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.footer-links-container {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

/* ===== Toast ===== */
/* ===== Toast ===== */
.toast {
    position: fixed;
    top: 2rem;
    right: 2rem;
    transform: translateX(120%);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.5rem;
    background: #FFFFFF;
    border-left: 4px solid var(--accent-primary);
    box-shadow: var(--shadow-md);
    border-radius: var(--border-radius-sm);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal) cubic-bezier(0.16, 1, 0.3, 1);
    /* Bouncy spring */
    z-index: 1000;
}

.toast.show {
    transform: translateX(0);
    opacity: 1;
    visibility: visible;
}

.toast.success {
    border-left-color: var(--accent-primary);
    /* Unified brand color */
}

.toast.error {
    border-left-color: var(--text-primary);
    /* Dark grey for errors */
}

.toast.warning {
    border-left-color: var(--warning);
}

.toast-message {
    font-size: 0.95rem;
    color: var(--text-primary);
}


.privacy-badge {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    /* Unified with text color */
    font-size: 0.85rem;
    font-weight: 500;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
    .preview-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .preview-arrow {
        padding-top: 0;
        transform: rotate(90deg);
        margin: -0.5rem 0;
    }
}

@media (max-width: 600px) {
    .app-container {
        padding: 1rem;
    }

    .header {
        margin-bottom: 2rem;
    }

    .logo h1 {
        font-size: 1.8rem;
    }

    .mode-btn {
        padding: 0.625rem 1.25rem;
        font-size: 0.9rem;
    }

    .upload-area {
        padding: 3rem 1.5rem;
    }

    .actions {
        flex-direction: column;
    }

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

    .footer-content {
        gap: 1.5rem;
    }

    .footer-section {
        text-align: center;
    }

    .footer-heading {
        justify-content: center;
    }

    .privacy-badge {
        justify-content: center;
    }
}