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

body {
    width: 100%;
    height: 100vh;
    background: linear-gradient(135deg, #0f0f1e 0%, #1a1a3e 50%, #0f1e2e 100%);
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    overflow: hidden;
    color: #ffffff;
}

.top-bar {
    position: fixed;
    background: rgba(15, 15, 30, 0.4);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 40px;
    z-index: 100;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.os-title {
    font-size: 24px;
    font-weight: 700;
    letter-spacing: 1px;
    background: linear-gradient(135deg, #6496ff 0%, #a78bfa 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.datetime {
    font-size: 14px;
    display: flex;
    gap: 20px;
    align-items: center;
}

.time {
    font-weight: 600;
    font-size: 16px;
}

.date {
    opacity: 0.8;
    font-weight: 500;
}

.desktop-apps {
    position: fixed;
    top: 100px;
    left: 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    z-index: 10;
}

.app-icon {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: transform 0.3s ease;
    user-select: none;
}

.icon-bg {
    width: 60px;
    height: 60px;
    background: rgba(100, 150, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(100, 150, 255, 0.3);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    transition: 0.3s;
}

.app-icon:hover .icon-bg {
    background: rgba(100, 150, 255, 0.3);
    border-color: rgba(100, 150, 255, 0.6);
    transform: scale(1.1);
}

.app-icon span {
    font-size: 12px;
    opacity: 0.8;
    font-weight: 500;
}

.window {
    position: absolute;
    background: rgba(20, 20, 40, 0.7);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    min-width: 340px;
    display: none;
    color: #ffffff;
    top: 120px;
    resize: both;
    overflow: auto;
}

.window.active {
    display: block;
}

.window-header {
    background: rgba(255, 255, 255, 0.05);
    padding: 16px;
    cursor: move;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 16px 16px 0 0;
    font-weight: 600;
    font-size: 14px;
    user-select: none;
}

.close-btn {
    background: none;
    border: none;
    color: #ffffff;
    cursor: pointer;
    font-size: 20px;
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0.7;
    transition: 0.2s;
}

.close-btn:hover {
    opacity: 1;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
}

.window-content {
    padding: 20px;
    font-size: 13px;
    line-height: 1.8;
}

.resize-handle {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 20px;
    height: 20px;
    cursor: nwse-resize;
    background: linear-gradient(135deg, transparent 50%, rgba(100, 150, 255, 0.3) 50%);
    border-radius: 0 0 16px 0;
}

.resize-handle:hover {
    background: linear-gradient(135deg, transparent 50%, rgba(100, 150, 255, 0.6) 50%);
}

#welcome {
    left: 80px;
    top: 150px;
    width: 400px;
}

#features {
    left: 520px;
    top: 150px;
    width: 400px;
}

#notes-app {
    left: 100px;
    top: 350px;
    width: 360px;
}

#tetris-app {
    left: 80px;
    top: 150px;
    width: 400px;
}

#backgrounds-menu {
    left: 50px;
}

.feature-button {
    position: fixed;
    bottom: 40px;
    right: 40px;
    background: rgba(100, 150, 255, 0.2);
    backdrop-filter: blur(20px);
    border: 1.5px solid rgba(100, 150, 255, 0.4);
    border-radius: 50px;
    padding: 14px 28px;
    color: #ffffff;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    z-index: 50;
    transition: 0.3s;
    box-shadow: 0 4px 16px rgba(100, 150, 255, 0.1);
    font-family: 'Inter', sans-serif;
}

.feature-button:hover {
    background: rgba(100, 150, 255, 0.35);
    border-color: rgba(100, 150, 255, 0.7);
    box-shadow: 0 8px 24px rgba(100, 150, 255, 0.2);
}

.feature-menu {
    position: fixed;
    bottom: 100px;
    right: 40px;
    background: rgba(20, 20, 40, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(100, 150, 255, 0.3);
    border-radius: 12px;
    padding: 12px 0;
    z-index: 49;
    min-width: 220px;
    display: none;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.feature-menu.show {
    display: block;
}

.menu-item {
    padding: 12px 20px;
    cursor: pointer;
    transition: 0.2s;
    border-left: 3px solid transparent;
    color: #cccccc;
    font-size: 13px;
    font-weight: 500;
}

.menu-item:hover {
    background: rgba(100, 150, 255, 0.15);
    color: #ffffff;
    border-left-color: #6496ff;
}

.bg-option {
    width: 70px;
    height: 70px;
    border-radius: 12px;
    cursor: pointer;
    border: 2px solid rgba(255, 255, 255, 0.2);
    transition: 0.3s;
    margin: 8px;
}

.bg-option:hover {
    border-color: #6496ff;
    transform: scale(1.08);
}

.bg-container {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-top: 10px;
    justify-content: center;
}

h2 {
    color: #6496ff;
    margin-bottom: 12px;
    font-size: 16px;
    font-weight: 600;
}

p {
    margin-bottom: 10px;
    opacity: 0.9;
    font-weight: 500;
}

.feature-list {
    list-style: none;
}

.feature-list li {
    margin-bottom: 10px;
    padding-left: 24px;
    position: relative;
    opacity: 0.9;
    font-weight: 500;
}

.feature-list li:before {
    content: "▸";
    position: absolute;
    left: 0;
    color: #6496ff;
    font-size: 16px;
}

.note-item {
    background: rgba(100, 150, 255, 0.12);
    padding: 10px 12px;
    margin-bottom: 8px;
    border-radius: 8px;
    border-left: 3px solid #6496ff;
    font-size: 12px;
    font-weight: 500;
}

.note-input {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid rgba(100, 150, 255, 0.3);
    border-radius: 8px;
    background: rgba(100, 150, 255, 0.08);
    color: #ffffff;
    font-size: 12px;
    font-weight: 500;
    margin-top: 10px;
    font-family: 'Inter', sans-serif;
}

.note-input::placeholder {
    color: rgba(255, 255, 255, 0.4);
}

.note-input:focus {
    outline: none;
    border-color: rgba(100, 150, 255, 0.6);
    background: rgba(100, 150, 255, 0.12);
}

#tetris-board {
    display: grid;
    grid-template-columns: repeat(10, 1fr);
    gap: 2px;
    width: 100%;
    background: rgba(0, 0, 0, 0.3);
    padding: 8px;
    border-radius: 8px;
    border: 1px solid rgba(100, 150, 255, 0.2);
    aspect-ratio: 1 / 2;
}

.tetris-cell {
    background: rgba(100, 150, 255, 0.1);
    border-radius: 4px;
}

.tetris-cell.active {
    background: linear-gradient(135deg, #6496ff 0%, #a78bfa 100%);
}

.tetris-btn {
    background: rgba(100, 150, 255, 0.3);
    border: 1px solid rgba(100, 150, 255, 0.5);
    color: #ffffff;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    font-size: 12px;
    transition: 0.2s;
    font-family: 'Inter', sans-serif;
}

.tetris-btn:hover {
    background: rgba(100, 150, 255, 0.5);
}