:root {
    --bg-action: #923737;
    --bg-pause: #416e46;
}

body {
    transition: background-color 0.3s ease;
}

main {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    text-align: center;
    display: grid;
    grid-template-rows: auto auto auto auto;
    row-gap: 40px;
    min-height: 100vh;
    align-content: center;
}

h1 {
    font-size: 2.5rem;
    color: #e8e6e3;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

p {
    font-size: 1.1rem;
    color: #b0b0b0;
}

p a {
    color: #4ecdc4;
    text-decoration: none;
    transition: color 0.2s ease;
}

p a:hover {
    color: #ff6b6b;
}

.timer-container {
    display: grid;
    grid-template-rows: 14vh 12vh 12vh auto;
    gap: 4vh;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.05);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.timer-container #countdown {
    height: 14vh;
    font-size: 14vh;
    font-weight: bold;
    color: #e8e6e3;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.4);
}

.timer-container #exercise_state {
    max-height: 12vh;
    height: 12vh;
    font-size: clamp(1rem, 6vw, 4.5rem);
    color: #b0b0b0;
    transition: color 0.3s ease;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.4);
}

.timer-container #exercise_name {
    height: 12vh;
    font-size: clamp(1rem, 6vw, 4.5rem);
    line-height: 1;
    white-space: nowrap;

    color: #b0b0b0;
    transition: color 0.3s ease;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.4);
}

.button-container {
    display: flex;
    justify-content: center;
    gap: 2rem;
}

.button-container #btn-start, .button-container #btn-reset {
    font-size: 1.3rem;
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    background-color: #4ecdc4;
    color: #fff;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: transform 0.2s ease, background-color 0.2s ease;
}

.button-container #btn-start:hover, .button-container #btn-reset:hover {
    background-color: #45b7b0;
    transform: translateY(-2px);
}

.button-container #btn-reset {
    background-color: #ff6b6b;
}

.button-container #btn-reset:hover {
    background-color: #e65b5b;
}