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

body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #1e1e2f, #2b2b45);
    color: white;
}

.app {
    background: #2f2f4f;
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    width: 320px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.4);
}

h1 {
    margin-bottom: 20px;
    font-size: 1.8rem;
}

.timer-box {
    background: #1a1a2e;
    padding: 30px;
    border-radius: 15px;
    margin-bottom: 20px;
}

#timer {
    font-size: 3rem;
    font-weight: bold;
    letter-spacing: 2px;
}

/* Buttons */
.controls,
.modes {
    margin-top: 15px;
}

button {
    padding: 10px 15px;
    margin: 5px;
    border: none;
    border-radius: 10px;
    background: #00c9a7;
    color: black;
    font-weight: bold;
    cursor: pointer;
    transition: 0.2s;
}

button:hover {
    background: #00f5d4;
    transform: translateY(-2px);
}

button:active {
    transform: scale(0.95);
}