:root {
    --bg: #ffffff;
    --text: #111;
}

body.dark {
    --bg: #0e0e0e;
    --text: #f5f5f5;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background 0.4s ease, color 0.4s ease;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: "Segoe UI", system-ui, sans-serif;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

/* CLOCK */
#clock {
    display: flex;
    gap: 0.15em;
    font-size: clamp(4rem, 12vw, 12rem);
    font-weight: 600;
    line-height: 1.1; /* FIX: prevents clipping */
}

/* DIGITS */
.digit {
    position: relative;
    width: 0.65em;
    height: 1.2em; /* FIX: extra vertical space */
    overflow: hidden;
}

.digit span {
    position: absolute;
    width: 100%;
    text-align: center;
    left: 0;
    top: 0;
    transform: translateY(0);
}

/* animation */
.enter {
    transform: translateY(100%);
    opacity: 0;
}

.enter-active {
    transform: translateY(0);
    opacity: 1;
    transition: transform 0.35s cubic-bezier(0.4,0,0.2,1),
                opacity 0.3s ease;
}

.exit-active {
    transform: translateY(-100%);
    opacity: 0;
    transition: transform 0.35s cubic-bezier(0.4,0,0.2,1),
                opacity 0.3s ease;
}

/* BUTTONS */
button {
    position: absolute;
    top: 20px;
    border: none;
    background: transparent;
    color: var(--text);
    font-size: 1.4rem;
    cursor: pointer;
    padding: 10px;
    border-radius: 10px;
    transition: background 0.3s ease, transform 0.2s ease;
}

button:hover {
    transform: scale(1.1);
    background: rgba(0,0,0,0.08);
}

body.dark button:hover {
    background: rgba(255,255,255,0.1);
}

.back-arrow {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 10;
}

body.dark .back-arrow:hover {
    background: rgba(255,255,255,0.1);
}

#themeToggle { top: 70px; left: 20px; }
#secondsToggle { right: 20px; }