:root {
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --text-color: #E0E0E0;
    --border-color: rgba(255, 255, 255, 0.2);
    --card-bg: rgba(255, 255, 255, 0.1);
    --button-bg: rgba(255, 255, 255, 0.15);
    --button-hover-bg: rgba(255, 255, 255, 0.25);
}

html {
    box-sizing: border-box;
    font-size: 100%;
}

*, *::before, *::after {
    box-sizing: inherit;
    margin: 0;
    padding: 0;
}

body {
    color: var(--text-color);
    font-family: var(--font-family);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    padding: 2rem;
    background: linear-gradient(-45deg, #5F7A61, #4A6372, #5F7A61, #4A6372);
    background-size: 400% 400%;
    animation: gradient 25s ease infinite;
}

@keyframes gradient {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.container {
    width: 100%;
    max-width: 600px;
    text-align: center;
}

.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 1.5rem;
    border: 1px solid var(--border-color);
    padding: 3rem;
    margin-bottom: 3rem;
}

#timer-display {
    font-size: clamp(3.5rem, 14vw, 6rem);
    font-weight: 300;
    margin-bottom: 1.5rem;
}

#timer-controls {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
}

#timer-presets {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

#custom-timer {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

button {
    background-color: var(--button-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-family: inherit;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.2s ease;
    min-height: 48px;
    padding: 0 1.5rem;
}

button:hover {
    background-color: var(--button-hover-bg);
}

#pause-resume-btn {
    font-size: 1.1rem; /* Slightly larger text */
    padding: 0.75rem 2rem; /* More padding */
    background-color: #A0C49D; /* Solid dark accent green */
    color: #1a1a1a; /* Dark text for contrast */
    border: none; /* Remove border */
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3); /* Subtle box-shadow */
    transition: all 0.2s ease;
    min-height: 48px; /* Ensure touch target */
}

#pause-resume-btn:hover {
    background-color: #8bb088; /* Slightly darker on hover */
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.4);
}

#custom-time-input {
    background-color: transparent;
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 12px;
    font-size: 1rem;
    text-align: center;
    width: 90px; /* Increased width */
    min-height: 48px;
}

#custom-time-input::placeholder {
    color: rgba(255, 255, 255, 0.7); /* Lighter placeholder for contrast */
}

.options {
    margin-top: 1rem;
    font-size: 0.9rem;
    opacity: 0.8;
}

.options label {
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

#content-section {
    text-align: left;
    max-width: 65ch;
    margin: 0 auto;
}

#content-section h2 {
    margin-bottom: 1rem;
    font-size: 1.8rem; /* Consistent font size for H2 */
    font-weight: 400; /* Consistent font weight for H2 */
}

#content-section p {
    font-size: 1.1rem; /* Slightly larger text */
    line-height: 1.8; /* Increased line-height for readability */
    margin-bottom: 1rem;
}

#content-section ul {
    list-style-position: inside;
    padding-left: 0;
}
#content-section li {
    margin-bottom: 0.5rem;
}

#content-section a {
    color: var(--text-color);
    text-decoration: underline;
}

footer {
    margin-top: auto;
    padding: 1rem;
    font-size: 0.8rem;
    opacity: 0.7;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}