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

:root {
    --md-sys-color-primary: #7C4DFF;
    --md-sys-color-on-primary: #FFFFFF;
    --md-sys-color-primary-container: #E8DDFF;
    --md-sys-color-on-primary-container: #21005E;
    --md-sys-color-secondary: #9575CD;
    --md-sys-color-on-secondary: #FFFFFF;
    --md-sys-color-surface: #FEFBFF;
    --md-sys-color-surface-variant: #E7E0EC;
    --md-sys-color-on-surface: #1C1B1F;
    --md-sys-color-on-surface-variant: #49454F;
    --md-sys-color-outline: #79747E;
    --md-sys-color-background: #F5F1FF;
    --md-sys-color-error: #BA1A1A;
    --md-sys-color-success: #006E1C;
}

.dark {
    --md-sys-color-primary: #D0BCFF;
    --md-sys-color-on-primary: #381E72;
    --md-sys-color-primary-container: #4F378B;
    --md-sys-color-on-primary-container: #EADDFF;
    --md-sys-color-secondary: #CCC2DC;
    --md-sys-color-on-secondary: #332D41;
    --md-sys-color-surface: #1C1B1F;
    --md-sys-color-surface-variant: #49454F;
    --md-sys-color-on-surface: #E6E1E5;
    --md-sys-color-on-surface-variant: #CAC4D0;
    --md-sys-color-outline: #938F99;
    --md-sys-color-background: #1C1B1F;
    --md-sys-color-error: #FFB4AB;
    --md-sys-color-success: #6DD58C;
}

html {
    font-size: clamp(14px, 0.9vw, 18px);
}

body {
    font-family: 'Roboto', sans-serif;
    background: var(--md-sys-color-background);
    color: var(--md-sys-color-on-surface);
    min-height: 100vh;
    transition: background 0.12s;
    line-height: 1.5;
}

.app-bar {
    background: var(--md-sys-color-surface);
    padding: clamp(8px, 1.5vw, 12px) clamp(12px, 3vw, 48px);
    display: flex;
    align-items: center;
    gap: clamp(8px, 2vw, 16px);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 10;
}

.app-bar h1 {
    font-size: clamp(16px, 1.2vw, 22px);
    font-weight: 500;
    flex: 1;
}

.app-bar img {
    width: clamp(24px, 4vw, 32px) !important;
    height: clamp(24px, 4vw, 32px) !important;
}

.app-bar .material-icons {
    font-size: clamp(24px, 2vw, 28px);
    color: var(--md-sys-color-primary);
}

.container {
    max-width: clamp(320px, 90vw, 1440px);
    margin: clamp(16px, 2vw, 32px) auto;
    padding: 0 clamp(12px, 3vw, 48px);
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 400px), 1fr));
    gap: clamp(16px, 2.5vw, 32px);
}

.card {
    background: var(--md-sys-color-surface);
    border-radius: clamp(12px, 1.5vw, 20px);
    padding: clamp(16px, 2vw, 32px);
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    transition: box-shadow 0.12s;
}

.card:hover {
    box-shadow: 0 4px 8px rgba(0,0,0,0.16), 0 2px 4px rgba(0,0,0,0.23);
}

.card h2 {
    font-size: clamp(18px, 1.3vw, 20px);
    font-weight: 500;
    margin-bottom: clamp(16px, 2vw, 24px);
    color: var(--md-sys-color-on-surface);
}

.input-container {
    margin-bottom: clamp(16px, 2vw, 24px);
}

.drop-zone {
    position: relative;
}

.drop-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--md-sys-color-primary-container);
    border: 2px dashed var(--md-sys-color-primary);
    border-radius: clamp(8px, 1.5vw, 12px);
    display: none;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: clamp(8px, 1.5vw, 12px);
    pointer-events: none;
    z-index: 1;
}

.drop-overlay .material-icons {
    font-size: clamp(36px, 4vw, 48px);
    color: var(--md-sys-color-primary);
}

.drop-overlay p {
    font-size: clamp(14px, 1vw, 16px);
    font-weight: 500;
    color: var(--md-sys-color-on-primary-container);
}

.drop-zone.drag-over .drop-overlay {
    display: flex;
}

.size-indicator {
    font-size: clamp(11px, 0.8vw, 12px);
    color: var(--md-sys-color-on-surface-variant);
    margin-top: clamp(6px, 1vw, 8px);
    text-align: right;
}

textarea, input {
    width: 100%;
    padding: clamp(12px, 1.5vw, 16px);
    border: 1px solid var(--md-sys-color-outline);
    border-radius: clamp(8px, 1.2vw, 12px);
    font-family: 'Roboto', monospace;
    font-size: clamp(13px, 0.9vw, 14px);
    background: var(--md-sys-color-surface);
    color: var(--md-sys-color-on-surface);
    transition: border-color 0.12s;
    line-height: 1.4;
}

textarea {
    min-height: clamp(100px, 12vw, 140px);
    resize: vertical;
}

textarea:focus, input:focus {
    outline: 2px solid var(--md-sys-color-primary);
    outline-offset: 2px;
    border-color: var(--md-sys-color-primary);
}

.button-group {
    display: flex;
    gap: clamp(8px, 1.5vw, 12px);
    margin-bottom: clamp(16px, 2vw, 24px);
    flex-wrap: wrap;
}

button {
    flex: 1;
    min-width: clamp(100px, 18vw, 120px);
    min-height: clamp(40px, 4vw, 48px);
    padding: clamp(10px, 1.2vw, 12px) clamp(16px, 2vw, 24px);
    border: none;
    border-radius: clamp(20px, 2.5vw, 24px);
    font-size: clamp(12px, 0.9vw, 13px);
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: clamp(6px, 1vw, 8px);
    transition: all 0.12s;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.btn-primary {
    background: var(--md-sys-color-primary);
    color: var(--md-sys-color-on-primary);
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.btn-primary:hover:not(:disabled) {
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
    transform: translateY(-1px);
}

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

.btn-secondary {
    background: var(--md-sys-color-secondary);
    color: var(--md-sys-color-on-secondary);
}

.btn-secondary:hover:not(:disabled) {
    opacity: 0.9;
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.icon-btn {
    width: clamp(40px, 5vw, 48px);
    height: clamp(40px, 5vw, 48px);
    min-width: clamp(40px, 5vw, 48px);
    padding: clamp(8px, 1.2vw, 12px);
    border-radius: 50%;
    background: transparent;
    flex: none;
}

.pin {
    font-size: clamp(36px, 3vw, 56px);
    font-weight: 700;
    text-align: center;
    margin: clamp(16px, 2vw, 24px) 0;
    color: var(--md-sys-color-primary);
    letter-spacing: clamp(8px, 1.5vw, 16px);
    font-family: 'Courier New', monospace;
    user-select: all;
}

.msg {
    text-align: center;
    padding: clamp(10px, 1.2vw, 12px) clamp(12px, 1.8vw, 16px);
    margin-top: clamp(8px, 1.2vw, 12px);
    border-radius: clamp(8px, 1.2vw, 12px);
    font-size: clamp(13px, 0.9vw, 14px);
}

.success {
    background: var(--md-sys-color-primary-container);
    color: var(--md-sys-color-on-primary-container);
}

.error {
    background: rgba(186, 26, 26, 0.15);
    color: var(--md-sys-color-error);
    border: 1px solid var(--md-sys-color-error);
}

.dark .error {
    background: rgba(255, 180, 171, 0.15);
    color: var(--md-sys-color-error);
}

#shareImg img, #loadImg img {
    max-width: 100%;
    margin-top: clamp(12px, 1.8vw, 16px);
    border-radius: clamp(8px, 1.5vw, 12px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.file-preview {
    display: flex;
    align-items: center;
    gap: clamp(8px, 1.5vw, 12px);
    padding: clamp(12px, 1.8vw, 16px);
    margin-top: clamp(12px, 1.8vw, 16px);
    background: var(--md-sys-color-surface-variant);
    border-radius: clamp(8px, 1.5vw, 12px);
}

.file-preview .material-icons {
    font-size: clamp(40px, 4vw, 48px);
    color: var(--md-sys-color-primary);
}

.file-preview p {
    font-size: clamp(13px, 0.9vw, 14px);
    color: var(--md-sys-color-on-surface-variant);
    word-break: break-all;
}

.file-item {
    position: relative;
    margin-top: clamp(8px, 1.5vw, 12px);
}

.file-item img {
    max-width: 100%;
    border-radius: clamp(8px, 1.5vw, 12px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.file-list-item {
    display: flex;
    align-items: center;
    gap: clamp(8px, 1.5vw, 12px);
    padding: clamp(8px, 1.2vw, 12px);
    margin-top: clamp(6px, 1vw, 8px);
    background: var(--md-sys-color-surface-variant);
    border-radius: clamp(8px, 1.2vw, 12px);
    position: relative;
}

.file-list-item:focus-within {
    outline: 2px solid var(--md-sys-color-primary);
    outline-offset: 2px;
}

.file-thumb {
    width: clamp(40px, 5vw, 48px);
    height: clamp(40px, 5vw, 48px);
    object-fit: cover;
    border-radius: clamp(6px, 1vw, 8px);
    flex-shrink: 0;
}

.file-icon {
    font-size: clamp(40px, 4vw, 48px);
    color: var(--md-sys-color-primary);
    flex-shrink: 0;
}

.file-name {
    flex: 1;
    font-size: clamp(13px, 0.9vw, 14px);
    color: var(--md-sys-color-on-surface-variant);
    word-break: break-word;
    overflow: hidden;
    text-overflow: ellipsis;
}

.remove-btn, .download-single-btn {
    width: clamp(32px, 4vw, 36px);
    height: clamp(32px, 4vw, 36px);
    min-width: clamp(32px, 4vw, 36px);
    padding: clamp(5px, 0.8vw, 6px);
    border-radius: 50%;
    background: var(--md-sys-color-error);
    color: white;
    flex: none;
    position: static;
}

.download-single-btn {
    background: var(--md-sys-color-primary);
}

.remove-btn:hover:not(:disabled), .download-single-btn:hover:not(:disabled) {
    opacity: 0.9;
    transform: scale(1.05);
}

.remove-btn:focus, .download-single-btn:focus {
    outline: 2px solid var(--md-sys-color-on-surface);
    outline-offset: 2px;
}

.remove-btn .material-icons, .download-single-btn .material-icons {
    font-size: clamp(18px, 2vw, 20px);
}

.file-size {
    font-size: clamp(10px, 0.75vw, 11px);
    color: var(--md-sys-color-on-surface-variant);
    opacity: 0.7;
}

.loading-spinner {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.help-btn {
    position: fixed;
    bottom: clamp(16px, 2.5vw, 24px);
    right: clamp(16px, 2.5vw, 24px);
    width: clamp(48px, 6vw, 56px);
    height: clamp(48px, 6vw, 56px);
    border-radius: 50%;
    background: var(--md-sys-color-primary);
    color: var(--md-sys-color-on-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
    transition: all 0.12s;
    z-index: 100;
}

.help-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 12px rgba(0,0,0,0.4);
}

.retry-msg {
    display: flex;
    align-items: center;
    gap: clamp(6px, 1vw, 8px);
    justify-content: center;
}

.retry-msg .material-icons {
    font-size: clamp(16px, 1.5vw, 18px);
    animation: spin 1s linear infinite;
}

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

@media (max-width: 480px) {
    .button-group {
        flex-direction: column;
    }
    button {
        width: 100%;
    }
}

@media (min-width: 1400px) {
    .container {
        max-width: clamp(1200px, 85vw, 1600px);
    }
}