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

:root {
    --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --glass-bg: rgba(255, 255, 255, 0.25);
    --glass-border: rgba(255, 255, 255, 0.18);
    --shadow: 0 8px 32px rgba(31, 38, 135, 0.37);
    --shadow-light: 0 4px 16px rgba(0, 0, 0, 0.1);
    --note-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    --text-primary: #2d3748;
    --text-secondary: #4a5568;
}

[data-theme="dark"] {
    --bg-gradient: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.2);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-light: 0 4px 16px rgba(0, 0, 0, 0.3);
    --note-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
    --text-primary: #f7fafc;
    --text-secondary: #e2e8f0;
}

body {
    font-family: 'Inter', sans-serif;
    height: 100vh;
    background: var(--bg-gradient);
    background-attachment: fixed;
    overflow: hidden;
    transition: background 0.3s ease;
}

.nav-bar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    padding: 1rem 2rem;
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-light);
}

.app-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.025em;
}

.nav-buttons {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.9rem;
    backdrop-filter: blur(10px);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: rgba(59, 130, 246, 0.2);
    color: #3b82f6;
    border: 1px solid rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    background: rgba(59, 130, 246, 0.3);
    transform: translateY(-1px);
}

.btn-danger {
    background: rgba(239, 68, 68, 0.2);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.btn-danger:hover {
    background: rgba(239, 68, 68, 0.3);
}

.theme-toggle {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--glass-bg);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

.canvas {
    height: 100vh;
    position: relative;
    padding: 100px 20px 20px;
    overflow: auto;
    cursor: grab;
}

.canvas:active {
    cursor: grabbing;
}

.canvas::-webkit-scrollbar {
    display: none;
}

.sticky-note {
    position: absolute;
    min-width: 200px;
    max-width: 350px;
    min-height: 120px;
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--note-shadow);
    cursor: move;
    user-select: none;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: center;
    font-size: 0.95rem;
    line-height: 1.5;
    resize: both;
    overflow: hidden;
}

.sticky-note.dragging {
    z-index: 10000;
    transform: rotate(3deg) scale(1.02);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.sticky-note.yellow { 
    background: linear-gradient(135deg, #fef9c7 0%, #f4e285 100%); 
    color: #744210; 
}
.sticky-note.pink { 
    background: linear-gradient(135deg, #fce4ec 0%, #f8bbd9 100%); 
    color: #880e4f; 
}
.sticky-note.mint { 
    background: linear-gradient(135deg, #e0f2f1 0%, #b2dfdb 100%); 
    color: #00695c; 
}
.sticky-note.lavender { 
    background: linear-gradient(135deg, #f3e5f5 0%, #e1bee7 100%); 
    color: #4a148c; 
}
.sticky-note.skyblue { 
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%); 
    color: #01579b; 
}

.note-header {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 0.75rem;
}

.color-picker {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--glass-border);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 10000;
}

.color-picker.active {
    opacity: 1;
    visibility: visible;
}

.color-title {
    text-align: center;
    margin-bottom: 1rem;
    font-weight: 500;
    color: var(--text-primary);
}

.color-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.75rem;
}

.color-btn {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    transition: transform 0.2s ease;
    position: relative;
}

.color-btn[data-color="yellow"] {
    background: linear-gradient(135deg, #fef9c7 0%, #f4e285 100%);
}
.color-btn[data-color="pink"] {
    background: linear-gradient(135deg, #fce4ec 0%, #f8bbd9 100%);
}
.color-btn[data-color="mint"] {
    background: linear-gradient(135deg, #e0f2f1 0%, #b2dfdb 100%);
}
.color-btn[data-color="lavender"] {
    background: linear-gradient(135deg, #f3e5f5 0%, #e1bee7 100%);
}
.color-btn[data-color="skyblue"] {
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
}

.color-btn:hover {
    transform: scale(1.1);
}

.delete-btn {
    background: rgba(239, 68, 68, 0.2);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.3);
    width: 32px;
    height: 32px;
    border-radius: 8px;
    font-size: 0.8rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border: none;
}

.delete-btn:hover {
    background: rgba(239, 68, 68, 0.3);
}

.note-textarea {
    width: 100%;
    height: 80px;
    border: none;
    background: transparent;
    resize: none;
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
    color: inherit;
    outline: none;
    overflow: hidden;
}

.color-swatch {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    margin-left: auto;
    border: 2px solid transparent;
    transition: all 0.2s ease;
}

.color-swatch:hover {
    transform: scale(1.1);
    border-color: rgba(255, 255, 255, 0.5);
}

@media (max-width: 768px) {
    .nav-bar {
        padding: 1rem;
    }
    
    .app-title {
        font-size: 1.3rem;
    }
    
    .btn {
        padding: 0.6rem 1.2rem;
        font-size: 0.85rem;
    }
    
    .canvas {
        padding: 90px 15px 15px;
    }
    
    .sticky-note {
        min-width: 250px;
        max-width: 90vw;
    }
}

@keyframes popIn {
    0% {
        transform: scale(0.3) rotate(-10deg);
        opacity: 0;
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

.pop-in {
    animation: popIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes tilt {
    0%, 100% { transform: rotate(0deg); }
    25% { transform: rotate(-2deg); }
    75% { transform: rotate(2deg); }
}

.sticky-note.tilt {
    animation: tilt 0.6s ease-in-out;
}