:root {
    --bg-color: #050505;
    --panel-bg: rgba(255, 255, 255, 0.02);
    --border-color: rgba(255, 255, 255, 0.06);
    --border-hover: rgba(255, 255, 255, 0.12);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent: #ffffff;
    --accent-bg: rgba(255, 255, 255, 0.02);
    --accent-hover: rgba(255, 255, 255, 0.05);
    --success: #10b981;
    --danger: #ef4444;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

/* Premium Glow Background */
.background-glow {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    background: radial-gradient(circle at 50% 40%, rgba(37, 99, 235, 0.12) 0%, rgba(30, 58, 138, 0.05) 40%, var(--bg-color) 80%);
}

/* Main Container */
.container {
    width: 100%;
    max-width: 480px;
    padding: 40px;
    border-radius: 16px;
    position: relative;
    z-index: 1;
    margin: 40px 20px;
}

.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.5);
}

header {
    text-align: center;
    margin-bottom: 32px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.logo i {
    font-size: 1.5rem;
    color: var(--text-main);
}

header h1 {
    font-size: 1.75rem;
    font-weight: 600;
    letter-spacing: -0.03em;
    color: var(--text-main);
}

header p {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 400;
}

/* Tabs */
.tabs {
    display: flex;
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 4px;
    margin-bottom: 24px;
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 10px;
    font-size: 0.9rem;
    font-family: inherit;
    font-weight: 500;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.tab-btn:hover {
    color: var(--text-main);
}

.tab-btn.active {
    background: var(--border-color);
    color: var(--text-main);
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease forwards;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Type Toggle */
.type-toggle {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.type-btn {
    flex: 1;
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    padding: 10px;
    font-size: 0.9rem;
    font-family: inherit;
    font-weight: 500;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.type-btn:hover {
    background: var(--accent-bg);
    color: var(--text-main);
}

.type-btn.active {
    background: var(--text-main);
    color: var(--bg-color);
    border-color: var(--text-main);
}

/* Send Tab */
.upload-area {
    border: 1px dashed var(--border-color);
    border-radius: 12px;
    padding: 40px 20px;
    text-align: center;
    transition: all 0.2s ease;
    background: rgba(255,255,255,0.01);
}

.upload-area.drag-over {
    border-color: var(--text-main);
    background: rgba(255,255,255,0.03);
}

.upload-icon {
    font-size: 2rem;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.upload-area h3 {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 6px;
}

.upload-area p {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 16px;
}

/* Buttons */
.btn {
    font-family: inherit;
    font-weight: 500;
    font-size: 0.9rem;
    border: 1px solid transparent;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-primary {
    background: var(--text-main);
    color: var(--bg-color);
    padding: 10px 20px;
}

.btn-primary:hover {
    background: #e4e4e7;
}

.btn-glow {
    background: var(--text-main);
    color: var(--bg-color);
    padding: 14px 24px;
    width: 100%;
    margin-top: 16px;
}

.btn-glow:hover {
    background: #e4e4e7;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.1);
}

.btn-block {
    width: 100%;
    padding: 14px;
}

.btn-icon {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    width: 32px;
    height: 32px;
    border-radius: 6px;
}

.btn-icon:hover {
    background: var(--border-hover);
    color: var(--text-main);
}

/* File Details */
.file-details {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 12px;
    margin-top: 16px;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 12px;
    overflow: hidden;
}

.file-type-icon {
    color: var(--text-muted);
    font-size: 1.2rem;
}

#file-name {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 220px;
    font-size: 0.9rem;
}

.hidden {
    display: none !important;
}

/* Text Area */
.text-area {
    width: 100%;
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 16px;
    color: var(--text-main);
    font-family: inherit;
    font-size: 0.95rem;
    resize: none;
    outline: none;
    transition: all 0.2s ease;
    min-height: 120px;
}

.text-area:focus {
    border-color: var(--text-muted);
}

.text-area.readonly {
    background: rgba(255, 255, 255, 0.01);
    cursor: default;
}

/* PIN Display */
.pin-display {
    text-align: center;
    margin-top: 16px;
    padding: 24px;
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    animation: fadeIn 0.3s ease forwards;
}

.pin-box {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin: 16px 0;
}

#generated-pin {
    font-size: 2.5rem;
    letter-spacing: 6px;
    color: var(--text-main);
    font-weight: 600;
}

.copy-btn {
    width: 40px;
    height: 40px;
}

.expiry-note {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Receive Tab */
.receive-area {
    text-align: center;
    padding: 10px 0;
}

.receive-icon {
    font-size: 2rem;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.receive-area h3 {
    font-size: 1rem;
    font-weight: 500;
}

.pin-input-group {
    margin: 20px 0;
}

#pin-input {
    width: 100%;
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    font-size: 1.5rem;
    text-align: center;
    letter-spacing: 6px;
    color: var(--text-main);
    font-family: inherit;
    font-weight: 600;
    outline: none;
    transition: all 0.2s ease;
}

#pin-input:focus {
    border-color: var(--text-muted);
}

#pin-input::placeholder {
    font-size: 1rem;
    letter-spacing: normal;
    color: var(--border-hover);
    font-weight: 400;
}

.file-preview {
    margin-top: 20px;
    animation: fadeIn 0.3s ease forwards;
}

.file-card {
    display: flex;
    align-items: center;
    gap: 16px;
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 12px;
    margin-bottom: 16px;
}

.file-card-icon {
    width: 40px;
    height: 40px;
    background: var(--border-hover);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-main);
    font-size: 1.2rem;
}

.file-card-details h4 {
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 4px;
    word-break: break-all;
}

.file-card-details p {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Text Preview Card */
.text-card {
    background: var(--accent-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.text-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background: rgba(255, 255, 255, 0.02);
    border-bottom: 1px solid var(--border-color);
}

.text-card-header h4 {
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
}

.text-card .text-area {
    border: none;
    border-radius: 0;
    background: transparent;
    min-height: 150px;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-main);
    color: var(--bg-color);
    padding: 12px 24px;
    border-radius: 30px;
    font-size: 0.9rem;
    font-weight: 500;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
}

.toast.error {
    background: var(--danger);
    color: white;
}

.toast.success {
    background: var(--text-main);
}

/* Footer */
.footer {
    position: fixed;
    bottom: 20px;
    left: 0;
    width: 100%;
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 400;
    letter-spacing: 0.02em;
}