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

:root {
    --primary-bg: #fafbfc;
    --card-bg: #ffffff;
    --text-primary: #1a1a1a;
    --text-secondary: #6b7280;
    --text-tertiary: #9ca3af;
    --border-color: #e5e7eb;
    --border-hover: #d1d5db;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.03);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.04);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Inter', 'Helvetica Neue', sans-serif;
    background: var(--primary-bg);
    min-height: 100vh;
    padding: 24px;
    color: var(--text-primary);
    transition: background-color var(--transition-base);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body.fullscreen-mode {
    background: var(--card-bg);
    padding: 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    animation: fadeIn 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

header {
    text-align: center;
    margin-bottom: 48px;
    padding-top: 16px;
}

header h1 {
    font-size: 2.75em;
    margin-bottom: 8px;
    font-weight: 600;
    letter-spacing: -0.03em;
    color: var(--text-primary);
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

header p {
    font-size: 1em;
    color: var(--text-secondary);
    font-weight: 400;
    letter-spacing: -0.01em;
}

.drop-zone {
    background: var(--card-bg);
    border: 2px dashed var(--border-color);
    border-radius: 16px;
    padding: 160px 40px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    margin-bottom: 24px;
    min-height: 320px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.drop-zone::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.02) 0%, rgba(168, 85, 247, 0.02) 100%);
    opacity: 0;
    transition: opacity var(--transition-base);
    pointer-events: none;
}

.drop-zone:hover {
    border-color: var(--border-hover);
    background: var(--primary-bg);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.drop-zone:hover::before {
    opacity: 1;
}

.drop-zone.drag-over {
    border-color: #6366f1;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.05) 0%, rgba(168, 85, 247, 0.05) 100%);
    transform: scale(1.005);
    box-shadow: var(--shadow-lg);
    border-style: solid;
}

.drop-zone.drag-over::before {
    opacity: 1;
}

.drop-zone-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    position: relative;
    z-index: 1;
}

.drop-icon {
    color: var(--text-tertiary);
    margin-bottom: 4px;
    transition: all var(--transition-base);
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.03));
    opacity: 0.7;
}

.drop-zone:hover .drop-icon {
    color: #818cf8;
    opacity: 0.85;
    transform: translateY(-4px) scale(1.05);
}

.drop-zone.drag-over .drop-icon {
    color: #818cf8;
    opacity: 0.9;
    transform: translateY(-4px) scale(1.1);
}

.drop-text {
    font-size: 1.5em;
    color: var(--text-primary);
    font-weight: 500;
    letter-spacing: -0.02em;
    transition: color var(--transition-base);
}

.drop-zone:hover .drop-text {
    color: var(--text-primary);
}

.drop-hint {
    font-size: 0.95em;
    color: var(--text-tertiary);
    font-weight: 400;
    letter-spacing: -0.01em;
}

.file-info {
    background: var(--card-bg);
    padding: 16px 24px;
    border-radius: 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    animation: slideDown 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

#fileName {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.95em;
    letter-spacing: -0.01em;
}

.clear-btn {
    background: var(--text-primary);
    color: #ffffff;
    border: none;
    padding: 10px 14px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 0.875em;
    transition: all var(--transition-fast);
    font-weight: 500;
    letter-spacing: -0.01em;
    box-shadow: var(--shadow-sm);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Inter', 'Helvetica Neue', sans-serif;
}

.clear-btn:hover {
    background: var(--text-primary);
    box-shadow: var(--shadow-md);
}

.clear-btn:active {
    box-shadow: var(--shadow-sm);
}

.clear-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    transition: opacity var(--transition-fast);
    opacity: 0.95;
    display: block;
    vertical-align: middle;
}

.clear-btn:hover .clear-icon {
    opacity: 1;
}

.clear-text {
    font-weight: 500;
    letter-spacing: -0.01em;
    line-height: 1;
    display: flex;
    align-items: center;
}

.content-area {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 48px;
    box-shadow: var(--shadow-md);
    margin-bottom: 24px;
    position: relative;
    border: 1px solid var(--border-color);
    animation: fadeInUp 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body.fullscreen-mode .content-area {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    height: 100vh;
    border-radius: 0;
    margin: 0;
    padding: 80px 64px 64px;
    overflow-y: auto;
    box-shadow: none;
    border: none;
    transition: all var(--transition-base);
    animation: fullscreenFadeIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes fullscreenFadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

body.fullscreen-mode .content-area.drag-over {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.05) 0%, rgba(168, 85, 247, 0.05) 100%);
    border: 2px dashed #6366f1;
}

.clear-btn-fullscreen {
    display: none;
    position: fixed;
    top: 32px;
    right: 32px;
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    color: #ffffff;
    border: none;
    padding: 12px 16px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 0.875em;
    font-weight: 500;
    transition: all var(--transition-fast);
    z-index: 1000;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    letter-spacing: -0.01em;
    animation: slideInRight 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Inter', 'Helvetica Neue', sans-serif;
}

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

body.fullscreen-mode .clear-btn-fullscreen {
    display: flex;
}

.clear-btn-fullscreen:hover {
    background: rgba(26, 26, 26, 1);
    box-shadow: var(--shadow-xl);
}

.clear-btn-fullscreen:active {
    box-shadow: var(--shadow-lg);
}

.clear-icon-fullscreen {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    transition: opacity var(--transition-fast);
    opacity: 0.95;
    display: block;
    vertical-align: middle;
}

.clear-btn-fullscreen:hover .clear-icon-fullscreen {
    opacity: 1;
}

.clear-text-fullscreen {
    font-weight: 500;
    letter-spacing: -0.01em;
    line-height: 1;
    display: flex;
    align-items: center;
}

.markdown-content {
    max-width: 100%;
    line-height: 1.75;
    color: var(--text-primary);
    font-size: 16px;
}

.markdown-content h1 {
    font-size: 2.5em;
    margin-top: 0.8em;
    margin-bottom: 0.6em;
    padding-bottom: 0.4em;
    border-bottom: 2px solid var(--border-color);
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.markdown-content h2 {
    font-size: 2em;
    margin-top: 1.2em;
    margin-bottom: 0.6em;
    padding-bottom: 0.3em;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.3;
}

.markdown-content h3 {
    font-size: 1.5em;
    margin-top: 1.2em;
    margin-bottom: 0.6em;
    color: var(--text-primary);
    font-weight: 600;
    letter-spacing: -0.01em;
    line-height: 1.4;
}

.markdown-content h4, .markdown-content h5, .markdown-content h6 {
    font-size: 1.25em;
    margin-top: 1em;
    margin-bottom: 0.5em;
    color: var(--text-primary);
    font-weight: 600;
    letter-spacing: -0.01em;
}

.markdown-content p {
    margin-bottom: 1.2em;
    color: var(--text-primary);
    line-height: 1.8;
}

.markdown-content ul, .markdown-content ol {
    margin-bottom: 1.2em;
    padding-left: 2em;
    color: var(--text-primary);
}

.markdown-content li {
    margin-bottom: 0.6em;
    line-height: 1.7;
}

.markdown-content code {
    background: rgba(99, 102, 241, 0.08);
    padding: 0.2em 0.5em;
    border-radius: 6px;
    font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
    font-size: 0.9em;
    color: #6366f1;
    border: none;
    font-weight: 500;
}

.markdown-content pre {
    background: #1a1a1a;
    padding: 20px;
    border-radius: 12px;
    overflow-x: auto;
    margin-bottom: 1.5em;
    border: none;
    box-shadow: var(--shadow-md);
    position: relative;
}

.markdown-content pre code {
    background: transparent;
    padding: 0;
    color: #e5e7eb;
    font-size: 0.9em;
    border: none;
    font-weight: 400;
}

.markdown-content blockquote {
    border-left: 4px solid #6366f1;
    padding-left: 20px;
    padding-right: 20px;
    padding-top: 8px;
    padding-bottom: 8px;
    color: var(--text-secondary);
    margin-bottom: 1.5em;
    font-style: normal;
    background: rgba(99, 102, 241, 0.04);
    border-radius: 0 8px 8px 0;
    margin-left: 0;
    margin-right: 0;
}

.markdown-content table {
    border-collapse: collapse;
    width: 100%;
    margin-bottom: 1.5em;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.markdown-content table th,
.markdown-content table td {
    border: 1px solid var(--border-color);
    padding: 12px 16px;
    text-align: left;
}

.markdown-content table th {
    background: var(--primary-bg);
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.markdown-content table td {
    color: var(--text-primary);
}

.markdown-content table tr:hover {
    background: rgba(99, 102, 241, 0.02);
    transition: background-color var(--transition-fast);
}

.markdown-content a {
    color: #6366f1;
    text-decoration: none;
    border-bottom: 1px solid rgba(99, 102, 241, 0.3);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.markdown-content a:hover {
    color: #4f46e5;
    border-bottom-color: #4f46e5;
}

.markdown-content img {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    margin: 1.5em 0;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.markdown-content img:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.markdown-content hr {
    border: none;
    border-top: 2px solid var(--border-color);
    margin: 2em 0;
    border-radius: 2px;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 16px;
    }

    header {
        margin-bottom: 32px;
    }

    header h1 {
        font-size: 2em;
    }

    .drop-zone {
        padding: 80px 24px;
        min-height: 280px;
        border-radius: 12px;
    }

    .drop-icon {
        width: 64px;
        height: 64px;
    }

    .drop-text {
        font-size: 1.25em;
    }

    .content-area {
        padding: 24px;
        border-radius: 12px;
    }

    body.fullscreen-mode .content-area {
        padding: 64px 24px 24px;
    }

    .clear-btn {
        padding: 8px 16px;
        font-size: 0.8em;
        gap: 6px;
    }

    .clear-icon {
        width: 14px;
        height: 14px;
    }

    .clear-btn-fullscreen {
        top: 16px;
        left: 16px;
        padding: 10px 20px;
        font-size: 0.8em;
        gap: 8px;
    }

    .clear-icon-fullscreen {
        width: 14px;
        height: 14px;
    }

    .markdown-content {
        font-size: 15px;
    }

    .markdown-content h1 {
        font-size: 2em;
    }

    .markdown-content h2 {
        font-size: 1.75em;
    }

    .markdown-content h3 {
        font-size: 1.35em;
    }
}

/* 通知样式 */
.notification {
    position: fixed;
    top: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    color: #ffffff;
    padding: 14px 28px;
    border-radius: 12px;
    box-shadow: var(--shadow-xl);
    z-index: 10000;
    font-size: 14px;
    max-width: 90%;
    text-align: center;
    animation: notificationSlideDown 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    font-weight: 500;
    letter-spacing: -0.01em;
}

@keyframes notificationSlideDown {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(-24px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0) scale(1);
    }
}

.notification.fade-out {
    animation: notificationFadeOut 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes notificationFadeOut {
    from {
        opacity: 1;
        transform: translateX(-50%) translateY(0) scale(1);
    }
    to {
        opacity: 0;
        transform: translateX(-50%) translateY(-24px) scale(0.95);
    }
}