/* --- GLOBAL COLORS --- */
:root {
    --primary: #2563eb;      /* Professional Blue */
    --secondary: #0891b2;    /* Cyan */
    --accent: #213a87;       /* Purple */
    --success: #10b981;      /* Green */
    --text-dark: #1e293b;    /* Slate Dark */
    --text-light: #64748b;   /* Slate Light */
}

/* --- RESET & BASE --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 24px;
    color: var(--text-dark);
}

/* --- CONTAINER --- */
.container {
    background: #ffffff;
    border-radius: 16px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    padding: 40px;
    max-width: 480px;
    width: 100%;
}

/* --- HEADER --- */
.header {
    text-align: center;
    margin-bottom: 36px;
}

.header h1 {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.header p {
    font-size: 0.875rem;
    color: var(--text-light);
    font-weight: 400;
}

/* --- UPLOAD AREA --- */
.upload-area {
    border: 2px dashed #cbd5e1;
    border-radius: 12px;
    padding: 48px 32px;
    text-align: center;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    background: #f8fafc;
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, var(--primary) 0%, transparent 60%);
    transform: translate(-50%, -50%);
    opacity: 0;
    transition: opacity 0.25s ease;
}

.upload-area:hover::before,
.upload-area.highlight::before {
    opacity: 0.05;
}

.upload-area:hover,
.upload-area.highlight {
    border-color: var(--primary);
    background: #f1f5f9;
}

.upload-content {
    pointer-events: none;
    position: relative;
    z-index: 1;
}

.upload-icon {
    width: 56px;
    height: 56px;
    color: var(--primary);
    margin: 0 auto 20px;
    display: block;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.upload-area:hover .upload-icon {
    color: var(--accent);
    transform: translateY(-4px);
}

.upload-area h2 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
    letter-spacing: -0.01em;
}

.upload-area p {
    font-size: 0.875rem;
    margin-bottom: 24px;
    color: var(--text-light);
    line-height: 1.5;
}

/* --- BUTTON --- */
.btn-upload {
    display: inline-block;
    background: var(--primary);
    color: #ffffff;
    padding: 10px 28px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.875rem;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: auto;
    border: none;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.btn-upload:hover {
    background: #1d4ed8;
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

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

/* --- FILE PREVIEW --- */
.file-result {
    display: none;
    text-align: center;
    padding: 20px 0;
    animation: fadeIn 0.3s ease-out;
}

.file-icon-large {
    font-size: 3rem;
    color: var(--success);
    margin-bottom: 20px;
    display: block;
    animation: scaleIn 0.3s ease-out;
}

@keyframes scaleIn {
    from {
        transform: scale(0.9);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.file-details {
    background: #f8fafc;
    border-radius: 12px;
    padding: 16px;
    margin: 20px 0;
    text-align: left;
    display: flex;
    align-items: center;
    gap: 14px;
    border: 1px solid #e2e8f0;
}

.file-thumb {
    width: 52px;
    height: 52px;
    border-radius: 8px;
    background: var(--secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ffffff;
    font-size: 1.375rem;
    overflow: hidden;
    flex-shrink: 0;
}

.file-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--text-dark);
    margin-bottom: 4px;
    word-break: break-all;
    line-height: 1.4;
}

.file-size {
    font-size: 0.8125rem;
    color: var(--text-light);
}

.action-buttons {
    display: flex;
    justify-content: center;
    margin-top: 24px;
}

.btn-reset {
    background: #ffffff;
    color: var(--text-dark);
    padding: 10px 28px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.875rem;
    border: 1px solid #cbd5e1;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn-reset:hover {
    background: #f8fafc;
    border-color: #94a3b8;
    transform: translateY(-1px);
}

/* --- LOADING & PROGRESS --- */
.loading-container {
    display: none;
    margin: 24px 0;
}

.loading-text {
    margin-bottom: 12px;
    font-size: 0.875rem;
    color: var(--text-dark);
    text-align: center;
    font-weight: 500;
}

.progress-bar-container {
    width: 100%;
    height: 6px;
    background: #e2e8f0;
    border-radius: 8px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: var(--primary);
    border-radius: 8px;
    transition: width 0.2s linear;
    position: relative;
    overflow: hidden;
}

.progress-bar::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.3) 50%,
        transparent 100%
    );
    animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* --- MESSAGES --- */
.message-box {
    display: none;
    padding: 12px 16px;
    border-radius: 8px;
    margin-top: 20px;
    font-size: 0.875rem;
    text-align: center;
    font-weight: 500;
}

.error-message {
    background: #fef2f2;
    color: #dc2626;
}

.success-message {
    background: #f0fdf4;
    color: var(--success);
}

/* --- UTILS --- */
.hidden {
    display: none !important;
}

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    50% { transform: translateX(5px); }
    75% { transform: translateX(-5px); }
}

/* --- RESPONSIVE --- */
@media (max-width: 600px) {
    .container {
        padding: 32px 24px;
    }

    .header h1 {
        font-size: 1.75rem;
    }

    .header p {
        font-size: 0.75rem;
    }

    .upload-area {
        padding: 40px 24px;
    }

    .upload-icon {
        width: 48px;
        height: 48px;
    }

    .file-thumb {
        width: 48px;
        height: 48px;
    }
}

@media (max-width: 400px) {
    .container {
        padding: 24px 16px;
    }

    .btn-upload,
    .btn-reset {
        padding: 9px 22px;
        font-size: 0.8125rem;
    }

    .upload-area {
        padding: 32px 16px;
    }
}