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

html, body {
    width: 100%;
    height: 100%;
    overflow-x: hidden;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    /* Background image - thay đổi đường dẫn ảnh ở đây */
    background-image: url('./images/background.png');
    background-size: cover;
    background-position: top left;
    background-repeat: no-repeat;
    background-attachment: fixed;
    min-height: 100vh;
    width: 100vw;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding: 20px;
    overflow-x: hidden;
    margin: 0;
}

/* Fallback gradient nếu ảnh không load được - ẩn đi để không che ảnh */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    z-index: -3;
    opacity: 0;
    pointer-events: none;
}

.container {
    width: 100%;
    max-width: 450px;
    margin-left: auto;
    margin-right: 20%;
}

.content-right {
    background: transparent;
    backdrop-filter: none;
    border-radius: 20px;
    padding: 30px;
    box-shadow: none;
    border: none;
    position: relative;
    overflow: hidden;
}

.content-right::before {
    display: none;
}

h1 {
    text-align: center;
    color: #f5d000;
    margin-bottom: 25px;
    font-size: 3.5em;
    font-weight: 900;
    text-shadow: 
        0 1px 0 #ccc,
        0 2px 0 #c9c9c9,
        0 3px 0 #bbb,
        0 4px 0 #b9b9b9,
        0 5px 0 #aaa,
        0 6px 1px rgba(0,0,0,.1),
        0 0 5px rgba(0,0,0,.1),
        0 1px 3px rgba(0,0,0,.3),
        0 3px 5px rgba(0,0,0,.2),
        0 5px 10px rgba(0,0,0,.25),
        0 10px 10px rgba(0,0,0,.2),
        0 20px 20px rgba(0,0,0,.15);
    position: relative;
    z-index: 1;
    transform: perspective(500px) rotateX(15deg);
    transition: all 0.3s ease;
}

h1:hover {
    transform: perspective(500px) rotateX(25deg) scale(1.05);
    text-shadow: 
        0 1px 0 #ccc,
        0 2px 0 #c9c9c9,
        0 3px 0 #bbb,
        0 4px 0 #b9b9b9,
        0 5px 0 #aaa,
        0 6px 1px rgba(0,0,0,.1),
        0 0 5px rgba(0,0,0,.1),
        0 1px 3px rgba(0,0,0,.3),
        0 3px 5px rgba(0,0,0,.2),
        0 5px 10px rgba(0,0,0,.25),
        0 10px 10px rgba(0,0,0,.2),
        0 20px 20px rgba(0,0,0,.15),
        0 0 20px rgba(245, 208, 0, 0.5);
}

.input-section {
    margin-bottom: 25px;
    position: relative;
    z-index: 1;
    padding: 20px;
    background: rgba(0, 0, 0, 0.1);
    border-radius: 20px;
    border: 1px solid rgba(245, 208, 0, 0.2);
    backdrop-filter: blur(5px);
}

.input-row {
    display: flex;
    gap: 20px;
    align-items: flex-end;
}

.input-group {
    flex: 1;
    margin-bottom: 0;
}

.input-group label {
    display: block;
    margin-bottom: 12px;
    color: #f5d000;
    font-weight: 700;
    font-size: 1.2em;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.input-group input {
    width: 100%;
    padding: 18px 20px;
    border: 3px solid rgba(245, 208, 0, 0.3);
    border-radius: 15px;
    font-size: 1.2em;
    font-weight: 600;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
    backdrop-filter: blur(10px);
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.1),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

.input-group input::placeholder {
    color: rgba(255, 255, 255, 0.7);
    font-weight: 500;
}

.input-group input:focus {
    outline: none;
    border-color: #f5d000;
    background: rgba(255, 255, 255, 0.15);
    box-shadow: 
        0 0 0 5px rgba(245, 208, 0, 0.2),
        0 15px 40px rgba(0, 0, 0, 0.2),
        inset 0 1px 0 rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.input-group input:hover {
    border-color: rgba(245, 208, 0, 0.6);
    background: rgba(255, 255, 255, 0.12);
    transform: translateY(-1px);
}

.button-section {
    display: flex;
    gap: 15px;
    margin-bottom: 25px;
    position: relative;
    z-index: 1;
}

.btn {
    flex: 1;
    padding: 15px 20px;
    border: none;
    border-radius: 12px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

.btn-secondary {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(240, 147, 251, 0.3);
}

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

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

.result-section {
    text-align: center;
    position: relative;
    z-index: 1;
}

.current-number {
    margin-bottom: 25px;
}

.current-number h2 {
    color: #f5d000;
    margin-bottom: 20px;
    font-size: 1.5em;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.number-display {
    font-size: 4em;
    font-weight: 900;
    color: #f5d000;
    text-shadow: 
        0 1px 0 #ccc,
        0 2px 0 #c9c9c9,
        0 3px 0 #bbb,
        0 4px 0 #b9b9b9,
        0 5px 0 #aaa,
        0 6px 1px rgba(0,0,0,.1),
        0 0 5px rgba(0,0,0,.1),
        0 1px 3px rgba(0,0,0,.3),
        0 3px 5px rgba(0,0,0,.2),
        0 5px 10px rgba(0,0,0,.25),
        0 10px 10px rgba(0,0,0,.2),
        0 20px 20px rgba(0,0,0,.15);
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    background: rgba(0, 0, 0, 0.1);
    border-radius: 20px;
    border: 2px solid rgba(245, 208, 0, 0.3);
    backdrop-filter: blur(10px);
    padding: 15px;
}

.number-display.jumping {
    animation: numberJump 0.1s ease;
    opacity: 0.7;
    filter: brightness(0.8);
}

@keyframes numberJump {
    0% { transform: scale(1) translateY(0); }
    50% { transform: scale(1.2) translateY(-10px); }
    100% { transform: scale(1.1) translateY(0); }
}

.used-numbers {
    margin-bottom: 25px;
}

.used-numbers h3 {
    color: #f5d000;
    margin-bottom: 20px;
    font-size: 1.4em;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.numbers-list {
    max-height: 200px;
    overflow-y: auto;
    padding: 20px;
    background: rgba(0, 0, 0, 0.15);
    border-radius: 15px;
    border: 2px solid rgba(245, 208, 0, 0.3);
    backdrop-filter: blur(10px);
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.1),
        inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

.empty-message {
    color: rgba(255, 255, 255, 0.7);
    font-style: italic;
    font-size: 1.1em;
    text-align: center;
    padding: 20px;
}

.number-item {
    display: inline-block;
    background: linear-gradient(135deg, #f5d000 0%, #ff6b35 100%);
    color: #000;
    padding: 10px 18px;
    margin: 6px;
    border-radius: 25px;
    font-weight: 700;
    font-size: 1.1em;
    animation: fadeIn 0.5s ease;
    box-shadow: 
        0 4px 15px rgba(245, 208, 0, 0.3),
        0 2px 8px rgba(0, 0, 0, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
}

.number-item:hover {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 
        0 8px 25px rgba(245, 208, 0, 0.4),
        0 4px 15px rgba(0, 0, 0, 0.3);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.8);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.stats {
    display: flex;
    justify-content: space-around;
    padding: 25px;
    background: rgba(0, 0, 0, 0.15);
    border-radius: 15px;
    border: 2px solid rgba(245, 208, 0, 0.3);
    backdrop-filter: blur(10px);
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.1),
        inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

.stats p {
    color: rgba(255, 255, 255, 0.9);
    font-weight: 600;
    font-size: 1.1em;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.stats span {
    color: #f5d000;
    font-weight: 800;
    font-size: 1.3em;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
    margin-left: 8px;
}

/* Responsive Design */
@media (max-width: 1200px) {
    .container {
        max-width: 400px;
        margin-right: 30px;
    }
    
    h1 {
        font-size: 3em;
    }
    
    .number-display {
        font-size: 3.5em;
    }
}

@media (max-width: 768px) {
    body {
        padding: 10px;
        justify-content: center;
    }
    
    .container {
        max-width: 100%;
        margin-right: 0;
    }
    
    .content-right {
        padding: 25px 20px;
    }
    
    h1 {
        font-size: 2.5em;
    }
    
    .input-row {
        flex-direction: column;
        gap: 15px;
    }
    
    .button-section {
        flex-direction: column;
    }
    
    .number-display {
        font-size: 3em;
    }
    
    .stats {
        flex-direction: column;
        gap: 10px;
    }
}

/* Custom Scrollbar */
.numbers-list::-webkit-scrollbar {
    width: 8px;
}

.numbers-list::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 4px;
}

.numbers-list::-webkit-scrollbar-thumb {
    background: #667eea;
    border-radius: 4px;
}

.numbers-list::-webkit-scrollbar-thumb:hover {
    background: #5a6fd8;
}